JP4650120B2 - Check valve with air plug and compressed air supply system using the same - Google Patents

Description

  The present invention relates to a compressed air supply source system in which a plurality of air compressors used in an air tool such as an air nailer and driven by an electric motor are used to double the discharge amount (air generation capability) of compressed air. The present invention relates to a check valve with an air plug suitable for use in a system. In particular, it relates to the connection of the secondary pressure side ports of the pressure reducing valves attached to the air tanks of a plurality of air compressors.

  Pneumatic tools that use compressed air as a driving source, such as nailers and drivers, are driven by high-pressure air supplied from an air compressor that generates high-pressure compressed air. Gasoline engines and electric motors are used as power sources for air compressors. Generally, an air compressor driven by a gasoline engine has a higher output and a higher discharge rate than those driven by an electric motor. However, an engine equipped with an electric motor is widely used because of problems of noise and exhaust gas. Yes. In addition, the discharge amount of an air compressor here means the compressed air production | generation capability per unit time.

  A commercial power source is widely used as a power source at a work site such as a construction site where a pneumatic tool is used. For example, a 100 V, 15 A power outlet is widely used as a representative power source in Japan. The discharge amount of compressed air obtained by driving the electric motor of the air compressor by the power of the power outlet is limited to obtaining compressed air of about 140 liters per minute even if a highly efficient motor is adopted. .

  In the work site, nailing operations such as floor boarding, wall boarding, and field boarding need to be performed continuously and in large quantities, and the nailing machine consumes a large amount of compressed air. Furthermore, screw tightening tools such as screwdrivers or impact drivers use a relatively large amount of compressed air in the tightening work per screw and a large amount of screw tightening work. In addition, the compressed air is consumed continuously. Accordingly, there is a problem of insufficient discharge amount of the air compressor used for the pneumatic tool.

  On the other hand, it is required to reduce the weight of pneumatic tools and air compressors so that they can be easily transported to and from the work site. In particular, at work sites such as interior construction in a building or condominium building, it is necessary to carry and reciprocate tools by hand to the upper floor using stairs, and it is required to facilitate carrying. For this reason, there is a case where it is necessary to use an air compressor that is made lighter or more compact by reducing the discharge amount in order to reduce the weight. In this case as well, there is a problem of insufficient discharge amount.

  In order to solve the shortage of compressed air discharge amount of the air compressor connected to the air tool, multiple air compressors with the same discharge capacity performance are connected in parallel to the air tool to compress multiple air compressors. Solution means for doubling the substantial air compressor discharge performance by running the machines in parallel can be considered.

  The inventor of the present application studied a parallel operation method for doubling discharge capacity performance by connecting two conventional portable air compressors in parallel. The following is not a publicly known technique, but the problem of the parallel operation method examined by the present inventors will be described.

  FIG. 6 shows an external view in which two portable air compressors (for 100 V, 15 A commercial power supply) are installed at a work site. One air compressor 5 includes an air tank 52 for generating high-pressure air in a compressor driven by a motor and storing the high-pressure air. The compressed air stored in the air tank 52 is guided to an air socket 54s for air plug connection through a pressure reducing valve 55 and a pressure gauge 56, and is nailed in the flow path of the air hose set 3 including the air plug 3p, the hose 3h and the socket 3s. It is sent to the air plug 7p of the machine 7 to drive the nailing machine 7. The pressure reducing valve 55 functions as a pressure regulator that converts the high-pressure air in the air tank 52 to a constant pressure that is lower than the pressure in the air tank and is suitable for driving the air tool. The air socket 54s is connected in parallel to another branched air socket 53s. An air socket 51s is connected to the high-pressure air tank 52, and it can be connected to a high-pressure tank or an auxiliary tank of another air compressor via an air hose. The other air compressor 4 is configured in exactly the same manner, and includes a high-pressure air tank 42, a pressure reducing valve 45, a pressure gauge 46, air sockets 53s and 54s, and an air socket 41s of the air tank 42.

  In the known connection method in which the nailer 7 is driven by only one air compressor 5, as described above, the electric motor of the compressor 5 is automatically activated when the pressure in the air tank 52 rises to the set maximum pressure. It is designed to restart automatically when it falls to the set pressure, but when the nailer 7 continues the nailing operation under the condition that the air consumption exceeds the generation amount The pressure in the air tank 52 drops below the set pressure of the pressure reducing valve 55, and finally the head of the nail is lifted due to insufficient striking force. At this point, the worker must stop the nail work and wait for the pressure in the air tank 52 to rise.

  As one solution to alleviate the problems caused by such a conventional connection method, it is conceivable to connect an additional air tank (not shown) to the air tank 52 of one air compressor 5. Since the entire tank volume increases due to the connection of the additional air tank, the amount of air that can be used by the nail driver 7 increases when the pressure in the air tank rises to the maximum pressure and the motor stops. However, since this method does not increase the air generation capacity, when the amount of air used by the nail driver 7 exceeds the amount of air generated by the air compressor 5, the pressure in the air tank 52 is set to the set pressure of the pressure reducing valve 55. Therefore, the problem that the nail head is lifted due to insufficient pressure of compressed air cannot be solved.

  As another connection means for solving the above-described problem, a compressed air supply source system using a first parallel connection system in which a plurality of air compressors 5 and 4 are connected in parallel to a single nailing machine 7 can be considered. . In the first parallel connection method, the air compressor 4 is used as a second air compressor in FIG. 6 and the air tank 42 and the air tank 52 are directly connected to each other. That is, the air tank 42 is provided with an air socket 41s directly connected to the air tank 42, and similarly, the air tank 52 is provided with an air socket 51s. The two air tanks 42 and 52 are directly connected to each other by the air hose set 1 including the air plugs 11p and 12p and the air hose 1h through the air sockets 41s and 51s. According to the first parallel connection method, the tank volume and the air generation amount are doubled, and the nailer 7 can be used continuously for a long time. Further, according to this first parallel connection method, when the current capacity of the main breaker of the switchboard at the work site is sufficiently large, for example, when a plurality of branch breakers having a capacity of 100 V and 15 A are provided, each branch breaker is provided. By connecting the air compressors 5 and 4 to the breakers one by one, it is possible to operate a plurality of air compressors 5 and 4 at the same time without causing the problem of breaker breakage. Further, in order to reduce the weight, it is possible to increase the discharge amount by using a plurality of air compressors whose load current is less than half of the current capacity of the outlet (for example, 100V, 15A).

  However, in the compressed air supply source system using the first parallel connection method, air sockets 51s and 41s must be added to the air tanks 52 and 42, respectively. In general, since the air tank is thin and has a circular arc surface, it is necessary to provide a mounting seat for the socket on the air tank, and the manufacturing cost of the air tank becomes high. Therefore, there is a drawback that the air compressor itself becomes expensive. Further, in many cases, since the mounting seat is provided by welding to the air tank, there is a drawback in that an advanced welding technique is required so that an air leakage failure due to poor welding does not occur.

  As a compressed air supply source system according to the second connection system in which the air compressors 5 and 4 are connected in parallel to one nailer 7, as shown in FIG. 6, two air compressors 5 and 4 are connected. The discharge side port decompressed by the normally used pressure reducing valves 55 and 45 is provided with an air socket 54s and another air socket 53s branched, and the air hose set 2 including the air plugs 21p and 22p and the air hose 2h is used. Thus, it is conceivable to connect the air socket 53s of the air compressor 5 and the air socket 43s of the air compressor 4 to each other. The air generation amount can be doubled by this second parallel connection method. Generally, a pressure gauge and a plurality of air sockets are connected to the secondary side of the pressure reducing valves 55 and 45 using a commercially available inexpensive manifold (manifold). According to the connection method of the air socket using the manifold, the mounting seat of the air socket can be made cheaper than the first parallel connection method, and advanced welding technology is not required.

  FIG. 7 is a system block diagram of a compressed air supply source system according to the second parallel connection method. The primary pressure side ports of pressure reducing valves 55 and 45 are connected to air tanks 52 and 42, and the secondary pressure side ports thereof are connected to pressure gauges 56 and 46, dual air sockets 54s and 53s, and 44s and 43s, respectively. Has been. An air socket 43s of the air compressor 4 is connected to the air socket 53s of the air compressor 5 by an air hose set 2 including air plugs 21p and 22p and an air hose 2h. On the other hand, a nailer 7 having an air plug 7p is connected to the air socket 54s of the air compressor 5 through an air hose set 3 including an air plug 3p, an air socket 3s, and an air hose 3h.

  In general, in order to ensure safety, the discharge ports of the air tanks 52 and 42 of the air compressors 5 and 4 are connected to pressure reducing valves 55 and 45 having a relief function, and high pressure air (primary pressure) stored in the air tank is combined. ) It is designed to discharge air pressure (secondary pressure) P2 obtained by reducing P1 to a set pressure of low pressure or high pressure necessary for the pneumatic tool. Pressure gauges 56 and 46 are connected to the secondary pressure side of the pressure reducing valve so that the secondary pressure can be observed. In general, the functions of the pressure reducing valves 55 and 45 have the following characteristics.

  (1) When the secondary pressure P2 is equal to the set pressure Ps (when P2 = Ps) and the primary pressure P1 is higher than the secondary pressure P2 (when P1 ≧ P2), the secondary pressure P2 is increased from the primary pressure side port M1. The valve in the air flow path to the next pressure side port M2 is closed.

  (2) When the secondary pressure P2 is lower than the set pressure Ps (when P2 <Ps), and when the primary pressure P1 is higher than the secondary pressure P2 (when P1> P2), the secondary pressure is supplied from the primary pressure side port M1. A valve in the air flow passage to the pressure side port M2 is opened, and the compressed air flows from the primary pressure side port M1 to the secondary pressure side port M2.

  (3) When the secondary pressure P2 is lower than the set pressure Ps (when P2 <Ps) and the primary pressure P1 is lower than the secondary pressure P2 (when P1 <P2), the compressed air is in the secondary pressure side port. It will be in the state which flows from M2 to the primary pressure side port M1 (it will be in the state of a reverse flow).

  (4) When the secondary pressure P2 is higher than the set pressure Ps (when P2> Ps) and the primary pressure P1 is higher than the secondary pressure P2 (when P1> P2), the secondary having the secondary pressure P2 A part of the compressed air in the pressure side port M2 flows into the atmosphere as the air pressure Po (the relief function is activated).

  In particular, the characteristic of the item (4) is in a state where a so-called relief function is working. In this relief function, when the secondary pressure P2 is lowered to the set pressure Ps, the air in the piping such as an air hose is released to the atmosphere, and the pressure gauges 56 and 46 indicate the correctly set secondary pressure (P2 = Ps). And when the secondary pressure P2 rises above the set pressure Ps for some reason, it is necessary to release excess compressed air into the atmosphere in order to ensure safety or prevent excessive driving. It is an indispensable function. In addition, the pressure reducing valves 55 and 45 increase the secondary pressure P2 when the pressure P1 of the primary pressure side port M1 stored in the air tanks 52 and 42 decreases as in the characteristic shown in the above item (3). The compressed air flows back from the secondary pressure side port M2 to the primary pressure side port M1.

  Therefore, according to the second parallel connection method shown in FIG. 7, due to the relief function characteristic and the reverse flow characteristic of the pressure reducing valve, when the air hose set 2 is connected as shown in FIG. If the set pressures are not equal to each other, the relief function of these pressure reducing valves is activated, and air flows out from the pressure reducing valve on the lower set pressure side to the atmosphere side. This outflow continues until the set pressures of the pressure reducing valves can be adjusted equally.

  On the other hand, the set pressure Ps of the pressure reducing valve changes by several percent depending on the flow rate of the compressed air and the primary pressure P1, and therefore the nail driver 7 is used even if the set pressure Ps of the pressure reducing valves 55 and 45 is adjusted equally. During this time, the set pressure may be out of balance and air outflow may recur.

  Therefore, in the compressed air supply source system using the parallel connection system shown in FIG. 7, it takes time to set the pressures of the two pressure reducing valves 55 and 45, and air is wasted to the atmosphere during adjustment. Further, even if the pressure is set once, the balance of the set pressure may be lost during use, and air may be wasted into the atmosphere. That is, the pressure reducing valve has a relief function, and when the pressure at the primary pressure side port M1 (air tank side) of the pressure reducing valve becomes low, the pressure at the secondary pressure side port M2 becomes slightly higher than the setting. Because of this characteristic, there is a problem that air continues to leak from the pressure reducing valves 55 and 45 into the atmosphere.

  Accordingly, a main object of the present invention is to provide a compressed air supply source system in which at least two air compressors are connected in parallel, and wasteful consumption of compressed air is reduced.

  Another object of the present invention is to provide an air plug suitable for a compressed air supply system in which a plurality of air compressors are connected in parallel.

  Still another object of the present invention is to provide a compressed air supply system that is simple in structure and pressure adjustment and can be constructed at low cost, and a check valve with an air plug used therefor.

  Of the inventions disclosed in the present application, typical features will be described as follows.

  According to one aspect of the present invention, at least first and second air compressors and a check valve are provided, and the first and second air compressors are connected in parallel via the check valve. A compressed air supply system for supplying compressed air, wherein each of the first and second air compressors includes an air compressor driven by a motor and a compression generated by the air compressor. An air tank for storing air, a plurality of discharge ports for supplying compressed air below a predetermined set pressure, a primary pressure side port communicates with the air tank, and a secondary pressure side port is common to the plurality of discharge ports And a pressure reducing valve for reducing the air pressure of the primary pressure side port to a set pressure at the secondary pressure side port, wherein the air pressure of the primary pressure side port or the secondary pressure side port is the set value If lower than pressure When the primary pressure side port and the secondary pressure side port communicate with each other, and the air pressure of the secondary side pressure port is higher than the set pressure, via a relief flow passage branched from the secondary side pressure port A pressure reducing valve configured to communicate with the atmosphere, and the check valve includes an outflow side connection portion connected to one of the plurality of discharge ports of the first air compressor; An inflow side connection portion that communicates with one of the plurality of discharge ports of the second air compressor; and an inflow side connection portion that is inserted into the air flow path that leads from the inflow side connection portion to the outflow side connection portion. And a check valve body portion mounted with a check valve body that allows air to flow only in one direction from the outlet to the outlet connection portion, and another one of the plurality of discharge ports of the first air compressor Is an air supply port for the pneumatic tool.

  According to another feature of the present invention, the check valve is characterized in that each of the outflow side connection portion and the inflow side connection portion is formed in the form of an air plug.

  According to still another aspect of the present invention, the check valve is screwed with the discharge port of the air compressor by a screw portion formed in the outflow side connection portion, and the inflow side connection portion is It is formed by an air plug type.

  According to still another feature of the present invention, the check valve has the set pressure such that compressed air of high-pressure specifications is obtained at the plurality of discharge ports.

  According to still another feature of the present invention, the air tank of the first air compressor further has a discharge port for obtaining compressed air of low-pressure specification via a pressure reducing valve having a set pressure of low-pressure specification. Is provided.

  According to still another aspect of the invention, the rated current of the air compressor is less than or equal to half of the current capacity of an outlet that supplies power to the air compressor.

  According to still another feature of the present invention, the check valve with an air plug is inserted into the inflow side connection portion and the outflow side connection portion, and the air flow path leading from the inflow side connection portion to the outflow side connection portion. An air plug comprising a check valve body portion for mounting a check valve body for flowing compressed air only in one direction from the inflow side connection portion to the outflow side connection portion, the inflow side connection portion and Each of the outflow side connection portions is formed in an air plug type that can be connected to an air socket.

  According to still another aspect of the present invention, the check valve with an air plug has an identification mark that can distinguish the inflow side connection portion and the outflow side connection portion that are in the form of an air plug, or the inflow side connection portion to the outflow side. An identification mark capable of distinguishing the directionality of the air flow passage toward the connecting portion is provided on the surface of the check valve body portion.

  According to still another aspect of the present invention, the check valve with an air plug is a check valve with an air plug for use when connecting at least the first and second air compressors in parallel. The first air compressor is used as a parent machine side for supplying compressed air to an air tool, and the second air compressor is used as a child machine side for sending compressed air to the parent machine side. When connecting between the air socket on the master unit side and the air socket on the slave unit side by a check valve with an air plug, an arrow indicating the direction in which compressed air flows on the surface of the check valve body portion Or a mark indicating the parent device on the parent device connection side or a mark indicating the child device on the child device connection side.

  According to the above-described feature of the present invention, since the check valve is used in the parallel connection system of the plurality of air compressors, the compressed air generated by the plurality of air compressors is reduced by the pressure reducing valve of the air compressor. It is effectively utilized without being exhausted from the relief flow passage to the atmosphere, and the discharge amount can be doubled by connecting at least two air compressors in parallel.

  Furthermore, according to the above-described feature of the present invention, the air plug check valve with the identification mark indicating the directionality of the compressed air flow path is used for the parallel connection of the plurality of air compressors. Can prevent misdirection when connecting.

  Furthermore, in the case of a pneumatic tool of low pressure specification, the pressure drop can be eliminated even when the air consumption exceeds the discharge amount for one air compressor. In addition, if two small products are connected, a discharge amount equivalent to that of a large product can be obtained.

  The above and other features of the present invention, and the above and other advantages will become more apparent from the following description of the present specification and the accompanying drawings.

  Hereinafter, embodiments of a compressed air supply system and a check valve according to the present invention will be described with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

[First Embodiment]
FIG. 1 is a system block diagram of a compressed air supply system according to the first embodiment of the present invention, and FIG. 2 is a configuration diagram of a check valve with an air plug used in the compressed air supply system shown in FIG. FIG. 3 shows a configuration diagram of a pressure reducing valve used in the compressed air supply source system shown in FIG.

  As shown in FIG. 1, the compressed air supply source system 100 includes a first air compressor 5 (hereinafter, “first air compressor” is referred to as “master air compressor”) and second air. The compressor 4 (hereinafter, the “second air compressor” is referred to as a “slave unit side air compressor”). The master-side air compressor 5 includes an electric motor 58, an air compression unit 57 driven by the motor 58, an air tank 52 that stores compressed air generated by the air compression unit 57, and a predetermined set pressure or less. A plurality of outlets 53s and 54s, for example, comprising air sockets, a primary pressure side port M1 communicates with the air tank 52, and a secondary pressure side port M2 is provided with a plurality of outlets 53s and 54s, and a pressure reducing valve 55 for reducing the air pressure P1 of the primary pressure side port M1 to the set pressure P2 or less in the secondary pressure side port M2, and a secondary pressure side port of the pressure reducing valve 55 And a pressure gauge 56 for observing the air pressure P2 at M2. Similarly, the handset side air compressor 4 includes a motor 48, an air compression unit 47, an air tank 42, a pressure reducing valve 45, a pressure gauge 46, and a plurality of discharge ports 43s and 44s made of, for example, an air socket. Each of these members has the same functions or specifications as those of the master unit side air compressor 5.

  The pressure reducing valves 55 and 45 have the same functions, and their structures are as shown in FIG. In the pressure reducing valve 55 (or 45) shown in FIG. 3, the adjustment handle 101 for adjusting the set pressure Ps of the pressure reducing valve and the air flow path between the primary pressure side port M1 and the secondary pressure side port M2 are opened and closed. Valve 106, a valve spring 107 for applying a pressing force to the valve 106 in advance, a piston 104 for moving the valve 106, and expansion and contraction by the rotation of the handle 101 to change the operating load of the piston 104 Connected to the pressure regulating spring 102, the bonnet 103 that houses the piston 104 and the pressure regulating spring 102, the primary pressure side port M1 connected to the piping of the air tank 52 (or 42), and the piping of the discharge port 54s (or 44s). And a body 105 constituting the secondary pressure side port M2. Further, as shown in FIG. 3 (d), the pressure reducing valve 55 (or 45) is activated when the air pressure P2 of the secondary pressure side port M2 becomes higher than the air pressure P1 of the primary pressure side port M1. A relief flow passage 108 and a relief exhaust port 109 are provided for allowing a part of the air pressure P2 of the compressed air of the pressure side port M2 to escape to the atmosphere side as the air pressure Po. The four state diagrams (a), (b), (c), and (d) shown in FIG. 3 are respectively four of (a), (b), (c), and (d) described below. The state corresponding to one operation is shown. In the pressure reducing valve 45 used in the slave air compressor 4, the primary pressure of the primary pressure side port M1 is indicated as P1 ', and the secondary pressure of the secondary pressure side port M2 is indicated as P2'. . As will be described later, the secondary pressure P2 'is set to a value slightly lower than P2, but the function of each member is exactly the same as that of the pressure reducing valve 55.

  (A) When the secondary pressure P2 of the compressed air at the secondary pressure side port M2 is equal to the set pressure Ps (when P2 = Ps), the primary pressure P1 of the compressed air at the primary pressure side port M1 is the secondary pressure P2. When the pressure is higher than the above (when P1 ≧ P2), the valve 106 in the air flow path from the primary pressure side port M1 to the secondary pressure side port M2 is not pushed downward by the piston 104, so the valve 106 is closed. It becomes a state.

  (B) When the secondary pressure P2 is lower than the set pressure Ps (when P2 <Ps), and when the primary pressure P1 is higher than the secondary pressure P2 (when P1> P2), the secondary pressure from the primary pressure side port M1 The valve 106 in the air flow path to the pressure side port M2 is pushed downward by the piston 104 to be in an open state. As a result, the compressed air enters a normal state from the primary pressure side port M1 to the secondary pressure side port M2.

  (C) When the secondary pressure P2 is lower than the set pressure Ps (when P2 <Ps) and the primary pressure P1 is lower than the secondary pressure P2 (when P1 <P2), the compressed air is in the secondary pressure side port. It will be in the state which flows from M2 to the primary pressure side port M1. That is, this state shows a reverse flow characteristic in which, when the primary pressure P1 stored in the air tank decreases, the secondary pressure P2 increases and the compressed air flows backward from the secondary pressure side port M2 to the primary pressure side port M1.

  (D) When the secondary pressure P2 is higher than the set pressure Ps (when P2> Ps) and the primary pressure P1 is higher than the secondary pressure P2 (when P1> P2), Since the piston 104 that has received the secondary pressure P2 is pushed upward, the relief flow passage 108 provided at the center of the piston 104 is separated from the valve 106 and opened. As a result, the secondary pressure side port M2 side communicates with the atmosphere via the relief flow passage 108 in the center of the piston 104 and the branch passage of the relief exhaust port 109, and the secondary pressure P2 at the secondary pressure side port M2 is communicated. Compressed air having is released into the atmosphere as air pressure Po. A so-called relief function is activated. In particular, when the secondary pressure P2 is lowered to the set pressure Ps, this relief function releases the air in the piping such as an air hose to the atmosphere, and the secondary pressure (P2 = Ps) set correctly by the pressure gauges 56 and 46 is obtained. When the secondary pressure P2 rises above the set pressure Ps for any reason, and to prevent excess excessive air from being released into the atmosphere in order to ensure safety or prevent excessive driving. It is an indispensable function.

  The nailing machine 7 has an air plug 7p for connecting an air hose, and the air socket of the main unit-side air compressor 5 by the air hose set 3 including the air socket 3s, the air hose 3h, and the air plug 3p connected to the air plug 7p. 54s. One discharge port (air socket) 43s of the slave unit side air compressor 4 is connected to one discharge port (air) of the master unit side air compressor 5 via the air hose set 2 and the check valve 10 with an air plug according to the present invention. Socket) 53s. The air hose set 2 includes an air plug 22p connected to the air socket 43s, an air hose 2h, and an air socket 21s connected to one end of the check valve 10 with an air plug.

  The block diagram of the check valve 10 with an air plug according to the present invention is shown in FIG. As shown in FIG. 2A, the check valve 10 with an air plug includes an inflow side connection portion 11 a, an outflow side connection portion 11 b, and a check valve body portion 12. In the present embodiment, the inflow side connection portion 11a and the outflow side connection portion 11b are formed in an air plug shape. An advantage of forming the connecting portions 11a and 11b in the shape of an air plug is that an air socket is generally used as the discharge port (compressor side socket) 53s of the air compressor 5, so that the air plug type connecting portion 11b is formed as an air plug. It can be connected to the socket 53s. On the other hand, as an air hose set (2) for connecting the handset side air compressor 4, a general air hose set composed of an air plug (22p) -air hose (2h) -air socket (21s) is used. The air plug type connecting portion 11a can be connected to the air socket 21s on the air hose set side. The connection shape of both end portions of the check valve with air plug 10 may be other shapes according to the connection shapes on the air hose 2 side and the air compressor 5 side. The check valve body portion 12 has a cylindrical shape, and is integrally formed with the outflow side connection portion (air plug) 11b in this embodiment. In the hollow interior of the cylindrical check valve body 12, there is a check valve body (piston) 14 that slides on the hollow inner peripheral surface, and the check valve body 14 is pressed in the direction of the inflow side connection portion 11 a. A spring 15 is mounted. A screw portion 13 is formed on the hollow inner peripheral surface of the check valve body portion 12, and after the check valve body 14 and the spring 15 are assembled in the hollow inside of the check valve body portion 12, The air plug 11a is screwed into the screw portion 13.

  The check valve body 14 has, on the inflow side connecting portion 11a side, a central conical protrusion 14a and a peripheral flat portion 14b surrounding the central conical protrusion 14a, and further flows out of the peripheral flat portion 14b. It has a plurality of holes (flow passages) 14c penetrating on the side connection portion 11b side. A number of holes 14c are formed along the circumference of the peripheral flat portion 14b. When the compressed air is not supplied to the passage on the inflow side connecting portion 11a side or the compressed air is supplied to the passage on the outflow side connecting portion 11b side, the check valve body 14 is pressed against the spring 15 or the outflow side connecting portion. 11b side air pressure is received and pressed against the end face of the inflow side connection portion 11a. As a result, the conical protrusion 14a of the check valve body 14 closes the hollow portion of the inflow side connection portion 11a, and at the same time, many The hole 14c is closed by the cylindrical end face of the inflow side connecting portion 11a. That is, as described below, the check valve body 14 can block the flow of compressed air in the reverse direction from the outflow side connection portion 11b side to the inflow side connection portion 11a.

  As shown in FIGS. 2A and 2B, the operation of the check valve 10 with an air plug is as follows. When supplying compressed air from the handset side air compressor 4, the compressed air flowing in from the air plug 11 a of the inflow side connection portion resists the pressing force of the spring 15 as shown in FIG. Since the conical protruding portion 14a and the peripheral flat portion 14b of the check valve body 14 are separated from the cylindrical end surface of the inflow side connection portion 11a and the plurality of air flow passages 14c are opened, the inflow side connection portion (air plug ) It can pass from 11a to the outflow side connection part (air plug) 11b. On the other hand, as shown in FIG. 2B, when compressed air is to flow from the outflow side connection portion (air plug) 11b to the inflow side connection portion (air plug) 11a, air is added to the pressing force of the spring 15. As described above, the pressure acts to close the plurality of holes (flow passages) 14c of the check valve body 14, and therefore, from the outflow side connection portion (air plug) 11b to the inflow side connection portion (air plug) 11a. It does not allow the compressed air to pass therethrough.

  (C) of FIG. 2 is an external view of the check valve 10 with an air plug according to the present invention. On the surface of the check valve body 12, an arrow 16 indicating that compressed air flows in one direction, and a letter “child side” 17 indicating an inflow side connection part (air plug) 11 a on the handset side air compressor 4 side. The character “parent side” 18 indicating the outflow side connection part (air plug) 11b on the base unit side air compressor 5 side is displayed. These direction identification marks only need to be capable of determining the correct directionality of the compressed air, and therefore need only have at least one display.

In the compressed air supply source system 100 described above, the maximum pressure of the air compressors 57 and 47 stored in the air tanks 52 and 42 is, for example, 3 MPa, and the pressure is reduced at the secondary pressure side port M2 by the pressure reducing valves 55 and 45. The pressure of the decompressed compressed air becomes, for example, 2 MPa or less of the high pressure specification, and drives the nail driver 7 of the high pressure specification. The air pressure supplied to the nailing machine 7 needs to be adjusted to an appropriate pressure according to the operation of the nailing machine 7. This pressure adjustment is performed by the pressure reducing valves 45 and 55 according to the following adjustment procedure.
(1) First, the secondary pressure P2 ′ is required for the nailing machine 7 by turning the handle 101 of the pressure reducing valve 45 while looking at the pressure display P2 ′ of the pressure gauge 46 of the handset side air compressor 4. Adjust to about 5% lower than the pressure P2. That is, P2 ′ = 0.95 × P2. For example, when P2 = 2 MPa, P2 ′ = 1.9 MPa is set, and when P2 = 1 MPa, P2 ′ = 0.95 MPa. As a guide, P2 ′ may be set lower by 0.05 to 0.1 MPa than P2.
(2) Next, the secondary pressure P2 is adjusted to the required pressure of the nailing machine 7 by turning the handle 101 of the pressure reducing valve 55 while observing the pressure display P2 of the pressure gauge 56 of the master air compressor 5.

Next, the flow of compressed air in the compressed air supply system 100 shown in FIG. 1 will be described.
(1) When P2> P2 ′:
When the secondary pressure P2 of the pressure reducing valve 55 of the master unit side air compressor 5 is higher than the secondary pressure P2 ′ of the pressure reducing valve 45 of the slave unit side air compressor (slave unit) 4, FIG. As shown, since the check valve body 14 of the check valve 10 closes the flow path, the compressed air does not flow from the parent device side air compressor 5 to the child device side air compressor 4. Accordingly, since the secondary pressure P2 ′ of the secondary pressure side port M2 of the slave unit side pressure reducing valve 45 does not become higher than the set pressure Ps, the relief mechanism of the pressure reducing valve 45 does not operate and the relief flow passage 108 is not operated. The flow path from the relief exhaust port 109 to the relief exhaust port 109 is closed so that the compressed air does not flow unnecessarily into the atmosphere.
(2) When P2 = P2 ′:
The air consumption amount of the nailing machine 7 is large, and the discharge amount of the main unit side air compressor 5 becomes insufficient, and the secondary pressure P2 of the secondary pressure side port M2 of the pressure reducing valve 55 is higher than the initial set pressure Ps. When the pressure decreases to 5% or less and P2 = P2 ′, as shown in FIG. 2A, the check valve body 14 of the check valve 10 opens, so that the air tank 42 of the handset side air compressor 4 is opened. Compressed air stored in the air is decompressed by the pressure reducing valve 45 and flows to the discharge port 53 s of the base air compressor 5 via the air hose set 2. Further, the compressed air supplied to the discharge port 53s is supplied to the nail driver 7 by the hose set 3 including the air plug 3p, the air hose 3h, and the air socket 3s via the other discharge ports 54s. In this case, since the compressed air is supplied to the nailing machine 7 from both the parent machine side air compressor 5 and the child machine side air compressor 4, the discharge amount of the compressed air as the compressed air supply source system 100 is doubled. To do. The pressure of the compressed air supplied to the nailer 7 is about 5% lower than the initially set pressure, but there is no practical problem. Also in this case, since the secondary pressure P2 or P2 ′ of the secondary pressure side port M2 of the pressure reducing valve 45 or 55 does not become higher than the set pressure Ps, the operating state of the pressure reducing valves 45 and 55 is as shown in FIG. In the state shown in b), the relief flow passages 108 and 109 are closed, so that the compressed air does not flow out into the atmosphere. In this case, in order to start the operation of the check valve body 14 described above, it is necessary to consider the spring load of the biasing spring 15 in terms of design, but the spring load is compared with the secondary pressure P2 or P2 ′. It is so small that it can be ignored in practice.
(3) When P1 <P2 ′:
When the motor 58 of the master unit side air compressor 5 is stopped, the pressure P1 in the air tank 52 of the master unit side air compressor 5 is the pressure P2 ′ of the secondary pressure side port M2 of the slave unit side air compressor 4. May be lower. In this case, the pressure reducing valve 55 of the main unit side air compressor 5 is in the state shown in FIG. 3C, the valve 106 is opened, and the sub unit side air compressor 4 supplied via the check valve 10. The compressed air flows into the air tank 52 of the main unit side air compressor 5. Also in this case, the relief flow passages 108 and 109 of the pressure reducing valves 45 and 55 are in a closed state, so that the compressed air does not flow out into the atmosphere. That is, the compressed air that has flowed into the air tank 52 of the parent device side air compressor 5 from the child device side air compressor 4 is stored in the air tank 52.

  Therefore, in the compressed air supply source system 100 shown in FIG. 1, the pressure adjustment is easy by connecting two air compressors (5 and 4) in parallel using the check valve 10 with an air plug, and The discharge amount can be doubled without wastefully discharging compressed air into the atmosphere. Furthermore, since the check mark 10 with an air plug is displayed with an identification mark indicating the air flow direction on the surface thereof, an error in the connection direction can be prevented when the system 100 is configured.

[Second Embodiment]
FIG. 4 shows a configuration diagram of a compressed air supply source system 110 constituted by the master unit side air compressor 5 and the slave unit side air compressor 4 having the same specifications, and a check valve 10 ′. The compressed air supply system 110 for driving the nailing machine 7 and the low-pressure nailing machine 8 is related to. In FIG. 4, parts that are the same as those in FIG. 1 are given the same reference numerals, and functional descriptions thereof are omitted. However, in FIG. 4, note that the pressure reducing valves 55 and 45 are pressure reducing valves for obtaining the secondary pressures P2 and P2 ′ of the high pressure specifications (1 to 2.48 MPa) at the secondary pressure side port M2. Should. In the compressed air supply source system 110 shown in FIG. 4, pressure reducing valves 59 and 49 of low pressure specifications (0 to 0.98 MPa) are attached to the air tanks 52 and 42 of high pressure compressed air. That is, high pressure reducing valves 55 and 45 and low pressure reducing valves 59 and 49 are attached to the air tanks 52 and 42.

  High pressure pressure gauges 56, 46, high pressure air sockets 54s, 53s, 44s, 43s, and a check valve body 14 to be described later are provided on the secondary side of the high pressure pressure reducing valves 55, 45 via manifolds. And a check valve 10 ′ with an air plug. Further, low pressure pressure gauges 60, 63 and low pressure air sockets 62s, 61s, 65s, 64s are attached to the secondary side of the low pressure reducing valves 59, 49 via manifolds (manifolds).

  The check valve 10 'with an air plug of the main unit side air compressor 5 and the high pressure air socket 44s of the sub unit side air compressor 4 are connected by an air hose set 2 including an air hose 2h, an air socket 2s and an air plug 2p. Yes. Further, the high pressure air socket 54s of the master air compressor 5 and the air plug 7p of the high pressure nailing machine 7 are connected by an air hose set 3 including an air hose 3h, an air socket 3s and an air plug 3p. Further, the low-pressure air socket 61s of the master air compressor 5 and the low-pressure nailing machine 8 are connected by an air hose set 4 including an air hose 4h, an air socket 4s, and an air plug 4p via an air plug 8p.

  An air plug check valve 10 ′ used in the compressed air supply source system 110 has a structure shown in the cross-sectional views of FIGS. 5 (a) and 5 (b). The check valve with air plug 10 'has substantially the same structure as that shown in FIG.

  That is, the check plug with air plug 10 ′ includes an inflow side connection portion 11 a, an outflow side connection portion 11 b, and a check valve body portion 12. In particular, in the present embodiment, the inflow side connection portion 11a is formed in an air plug insertion shape, but the outflow side connection portion 11b is formed in a screwed shape having a screw portion 20, and the secondary pressure of the pressure reducing valve 55 is increased. It has a structure that can be screwed to the manifold (manifold) of the side port M2. The check valve body portion 12 has a cylindrical shape and is integrally formed with the outflow side connection portion (screwing portion) 11b. In the hollow interior of the cylindrical check valve body 12, there is a check valve body (piston) 14 that slides on the hollow inner peripheral surface, and the check valve body 14 is pressed in the direction of the inflow side connection portion 11 a. A spring 15 is mounted. A screw portion 13 is formed on the hollow inner peripheral surface of the check valve body portion 12, and after the check valve body 14 and the spring 15 are assembled in the hollow inside of the check valve body portion 12, The air plug 11a is screwed into the screw portion 13. The check valve body 14 has, on the inflow side connecting portion 11a side, a central conical protrusion 14a and a peripheral flat portion 14b surrounding the central conical protrusion 14a, and further flows out of the peripheral flat portion 14b. It has a plurality of holes (flow passages) 14c penetrating on the side connection portion 11b side, and has the same function as that shown in FIG.

  As shown in FIG. 5A, when compressed air flows from an air plug 11 a connected to the handset side air compressor 4 via a hose set 2 (not shown), the pressure of the compressed air is the pressing force of the spring 15. Since the check valve body 14 is overcome and the high pressure compressed air is discharged from the passage of the air plug 11a to the outlet side connection portion (screwed) to the manifold of the secondary pressure side port M2 of the main unit side pressure reducing valve 55. Part) 11b. On the other hand, as shown in FIG. 5B, high-pressure compressed air is supplied from the outflow side connecting portion (screwed portion) 11b screwed to the manifold of the secondary pressure side port M2 of the base side pressure reducing valve 55. When the air is about to flow, the air pressure acts in addition to the pressing force of the spring 15 and the check valve body 14 is closed, so that the compressed air flows from the passage of the outflow side connection portion 11b toward the passage of the slave unit side air plug 11a. Can not pass.

The pressure of the compressed air supplied to the high-pressure nailing machine 7 and the low-pressure nailing machine 8 is adjusted to an appropriate pressure according to the work of the high-pressure nailing machine 7 and the low-pressure nailing machine 8. There is a need. This pressure adjustment is performed by the pressure reducing valves 55, 45, and 59 in accordance with the following adjustment procedure.
(1) First, while looking at the pressure display P2 ′ of the high pressure gauge 46 of the handset side air compressor 4, the handle 101 of the high pressure pressure reducing valve 45 is turned to set the secondary pressure P2 ′ to the high pressure nailer. 7 is adjusted to be lower by about 5% than the required pressure P2 required. That is, P2 ′ = 0.95 × P2. For example, when P2 = 2 MPa, P2 ′ = 1.9 MPa is set, and when P2 = 1 MPa, P2 ′ = 0.95 MPa. As a guide, P2 ′ may be set lower by 0.05 to 0.1 MPa than P2.
(2) Next, while looking at the pressure display P2 of the high pressure gauge 56 of the main unit side air compressor 5, the handle 101 of the high pressure reducing valve 55 is turned so that the secondary pressure P2 is required for the high pressure nailing machine 7. Adjust to pressure.
(3) Next, while observing the pressure display P2L of the low-pressure pressure gauge 60 of the master-side air compressor 5, the handle 101 of the low-pressure pressure reducing valve 59 is turned to reduce the secondary pressure P2L of the secondary pressure side port M2. The required pressure of the nailing machine 8 is adjusted.
Next, the flow of compressed air in the compressed air supply system 110 shown in FIG. 4 will be described.
(1) When P2> P2 ′:
When the secondary pressure P2 of the high pressure reducing valve 55 of the master unit side air compressor 5 is higher than the secondary pressure P2 ′ of the low pressure reducing valve 45 of the slave unit side air compressor 4, the flow chart shown in FIG. As shown, since the check valve body 14 of the check valve 10 closes the flow path, the compressed air does not flow from the parent device side air compressor 5 to the child device side air compressor 4. Accordingly, since the secondary pressure P2 ′ of the secondary pressure side port M2 of the slave unit side pressure reducing valve 45 does not become higher than the set pressure Ps, the relief mechanism of the pressure reducing valve 45 does not operate and the relief flow passage 108 is not operated. The flow path from the relief exhaust port 109 to the relief exhaust port 109 is closed so that the compressed air does not flow unnecessarily into the atmosphere.
(2) When P2 = P2 ′:
The air consumption of the high-pressure nailing machine 7 is large, and the discharge amount of the master-side air compressor 5 becomes insufficient, so that the secondary pressure P2 of the secondary pressure-side port M2 of the high-pressure reducing valve 55 is initially set. When the pressure drops to 5% or less from the set pressure Ps of P2 and P2 = P2 ′, the check valve body 14 of the check valve 10 ′ opens as shown in FIG. The compressed air stored in the air tank 42 of the compressor 4 is depressurized by the pressure reducing valve 45 and flows to the discharge port 54 s of the main unit side air compressor 5 through the air hose set 2 and the check valve 10 ′. Further, the compressed air supplied to the discharge port 54s is supplied to the high-pressure nailer 7 by the air hose set 3 including the air plug 3p, the air hose 3h, and the air socket 3s. In this case, since the compressed air is supplied to the nailing machine 7 from both the master unit side air compressor 5 and the slave unit side air compressor 4, the discharge amount of the compressed air as the compressed air supply source system 110 is doubled. To do. The pressure of the compressed air supplied to the high-pressure nailer 7 is about 5% lower than the initially set pressure, but there is no practical problem. Also in this case, since the secondary pressure P2 or P2 ′ of the secondary pressure side port M2 of the pressure reducing valve 45 or 55 does not become higher than the set pressure Ps, the operating state of the pressure reducing valves 45 and 55 is as shown in FIG. In the state shown in b), the relief flow passages 108 and 109 are closed, so that the compressed air does not flow out into the atmosphere. In this case, as in the first embodiment, when the check valve body 14 starts operating, it is necessary to consider the spring load of the biasing spring 15 in terms of design. Since it is very small compared to the pressure P2 or P2 ′, it can be ignored in practice.
(3) When P1 <P2 ′:
When the motor 58 of the main unit side air compressor 5 is stopped or the air consumption of the low pressure type nailing machine 8 is large, the discharge amount of the main unit side air compressor 5 becomes insufficient, and the high pressure reducing valve 55, when the secondary pressure P2 of the secondary pressure side port M2 drops to 5% or more from the initial set pressure Ps, and P2 <P2 ′, the pressure in the air tank 52 of the main unit side air compressor 5 P1 may become lower than the pressure P2 ′ of the secondary pressure side port M2 of the slave unit side air compressor 4, and may satisfy P1 <P2 ′. In this case, the high pressure pressure reducing valve 55 of the main unit side air compressor 5 is in the state shown in FIG. 3C, the valve 106 is opened, and the sub unit side air compression supplied via the check valve 10 ′. The compressed air of the machine 4 flows into the air tank 52 of the parent machine side air compressor 5.

  In this case, the compressed air to the low-pressure nailing machine 8 is supplied to the air hose set 2 and the compressed air generated by the slave unit side air compressor 4 in addition to the compressed air generated by the master unit side air compressor 5. Since it is supplied via the high pressure reducing valve 55, the discharge amount supplied from the air tank 52 to the nail driver 8 via the low pressure reducing valve 59 is doubled. The pressure of the compressed air supplied to the low pressure nailing machine 8 can be maintained at a constant pressure of P2L if the pressure P1 in the air tank 52 is higher than the set pressure Ps = P2L of the low pressure reducing valve 59. In this case as well, the relief flow passages 108 and 109 of the pressure reducing valves 45 and 55 are closed, so that the compressed air does not flow out into the atmosphere.

  As will be apparent from the first and second embodiments described above, according to the present invention, a check valve is used in a parallel connection system of a plurality of air compressors. The compressed air generated by the air compressor is effectively utilized without being wasted into the atmosphere from the relief flow passage of the pressure reducing valve of the air compressor, and by connecting at least two air compressors in parallel The discharge amount can be doubled. For example, in the compressed air supply system 110 shown in FIG. 4, the current capacities of the motors 58 and 48 used for the two air compressors 5 and 4 are designed to be full with respect to the capacity of a normal outlet 100V, 15A. In this case, if the compressed air supply system of the present invention is applied, the discharge amount can be increased to 140 liters per minute / unit × 2 units = 280 liters per minute. That is, the discharge amount of compressed air can be doubled by connecting two air compressors in parallel according to the present invention.

  As another example, when the current capacity of the motors 58 and 48 is designed to be 100V, 7.5A, which is 1/2 or less of the capacity of a normal outlet 100V, 15A, the discharge amount of compressed air is halved. The size and weight of the air compressors 5 and 4 can be reduced to about half, and transportation to a work site such as a building site is facilitated. If the compressed air supply source system of the present invention is applied at a work site, a discharge amount equivalent to that of a single large product can be obtained. That is, it is possible to obtain a discharge amount comparable to that of a large product by using two small product air compressors that are convenient for transportation.

  As mentioned above, although the invention made | formed by this inventor was demonstrated based on various embodiment, this invention is not limited to the said embodiment, A various change is possible within the range which does not deviate from the summary.

The block diagram of the compressed air supply source system which concerns on the 1st Embodiment of this invention. The block diagram of the non-return valve used for the compressed air supply source system shown in FIG. The block diagram of the pressure-reduction valve used for the compressed air supply source system shown in FIG. The block diagram of the compressed air supply source system which concerns on the 2nd Embodiment of this invention. The block diagram of the non-return valve used for the compressed air supply source system shown in FIG. The external view of the compressed air supply source system in the examination stage of this inventor. The block diagram of the compressed air supply source system shown in FIG.

Explanation of symbols

1: Air hose set 1h: Air hose 2: Air hose set 2h: Air hose 3: Air hose set 3h: Air hose 3s: Air socket 4: Second air compressor (child unit side air compressor)
5: First air compressor (master air compressor) 7: Nail driver (high pressure specification)
7p: Air plug 8: Nail driver (low pressure specification) 8p: Air plug 10, 10 ': Check valve 11a: Inlet side connection (air plug)
11b: Outlet side connection part (air plug or screwed part) 11p: Air plug 12s: Air socket 12: Check valve body part 13: Screw part 14: Check valve body 14a: Central conical protruding part 14b: Peripheral flat part 14c : Hole (flow passage) 15: Spring for bias 16: Arrows 17 and 18: Identification mark 20: Screw part 21p: Air plug 21s: Air socket 22p: Air plug 41s: Air socket 42: Air tank 43s: Discharge port (air socket)
44s: Discharge port (air socket) 45: Pressure reducing valve 46: Pressure gauge 47: Air compression part 48: Electric motor 49: Pressure reducing valve (for low pressure)
51s: Air socket 52: Air tank 53s: Discharge port (air socket)
54s: Discharge port (air socket) 55: Pressure reducing valve 56: Pressure gauge 57: Air compression part 58: Electric motor 59: Pressure reducing valve (for low pressure)
60: Pressure gauge (for low pressure) 61s, 62s: Discharge port (air socket)
63: Pressure gauge (for low pressure) 64s, 65s: Discharge port (air socket)
100, 110: Compressed air supply source system 101: Adjustment handle 102: Pressure adjusting spring 103: Bonnet 104: Piston 105: Body 106: Valve 107: Valve spring 108: Relief flow passage 109: Relief exhaust port

Claims (13)

An air compressor driven by a motor, an air tank for storing compressed air generated by the air compressor, and a plurality of discharge ports commonly connected to the air tank for discharging compressed air below a predetermined set pressure And the primary pressure side port communicates with the air tank, and the secondary pressure side port communicates with the plurality of discharge ports, and the air pressure of the primary pressure side port is reduced to a set pressure at the secondary pressure side port. A pressure reducing valve, wherein when the air pressure at the primary pressure side port or the secondary pressure side port is lower than the set pressure, the primary pressure side port and the secondary pressure side port communicate with each other, and the secondary side An air pressure comprising a pressure reducing valve configured to communicate with the atmosphere via a relief flow passage branched from the secondary pressure port when the air pressure in the pressure port is higher than the set pressure. And an outflow side connection portion coupled to one of the plurality of discharge ports, an inflow side connection portion connectable to an air hose, and an air flow path leading from the inflow side connection portion to the outflow side connection portion A compression valve comprising a check valve body portion that is inserted and has a check valve body mounted with a check valve body that allows air to flow only in one direction from the inflow side connection portion to the outflow side connection portion. Air supply system.   The compressed air supply system according to claim 1, wherein each of the check valve is formed in an air plug form in each of the outflow side connection portion and the inflow side connection portion.   The check valve is screwed into the discharge port of the air compressor by a screw portion formed in the outflow side connection portion, and the inflow side connection portion is formed in an air plug type. Item 2. A compressed air supply system according to item 1.   The compressed air supply source according to any one of claims 1 to 3, wherein the check valve has the set pressure such that high-pressure compressed air is obtained at the plurality of discharge ports. system. Compressed air for supplying compressed air, comprising at least first and second air compressors and a check valve, the first and second air compressors being connected in parallel via the check valve A source system,
Each of the first and second air compressors supplies an air compression unit driven by a motor, an air tank that stores compressed air generated by the air compression unit, and compressed air that is equal to or lower than a predetermined set pressure. A plurality of discharge ports and a primary pressure side port communicate with the air tank, and a secondary pressure side port communicates with the plurality of discharge ports in common, and the air pressure of the primary pressure side port is A pressure reducing valve for reducing the pressure to a set pressure at the pressure side port, wherein the primary pressure side port and the secondary pressure side port when the air pressure of the primary pressure side port or the secondary pressure side port is lower than the set pressure Is connected, and when the air pressure at the secondary pressure port is higher than the set pressure, the pressure reduction is configured to communicate with the atmosphere through a relief flow passage branched from the secondary pressure port. Provided with a door,
The check valve communicates with an outflow side connection portion connected to one of the plurality of discharge ports of the first air compressor and one of the plurality of discharge ports of the second air compressor. An inflow side connecting portion that is inserted into the inflow side connecting portion and the outflow side connecting portion to the outflow side connecting portion, and a check that allows air to flow in only one direction from the inflow side connecting portion toward the outflow side connecting portion. And a check valve body portion equipped with a valve body,
The compressed air supply source system, wherein the other one of the plurality of discharge ports of the first air compressor is an air supply port for the air tool.   6. The compressed air supply source system according to claim 5, wherein each of the check valve is formed in an air plug type in each of the outflow side connection portion and the inflow side connection portion.   The check valve is screwed into the discharge port of the air compressor by a screw portion formed in the outflow side connection portion, and the inflow side connection portion is formed in an air plug type. Item 6. A compressed air supply system according to Item 5.   The compressed air supply source according to any one of claims 5 to 7, wherein the check valve has the set pressure such that high-pressure compressed air is obtained at the plurality of discharge ports. system.   9. The air tank of the first air compressor is further provided with a discharge port for obtaining low-pressure compressed air through a pressure reducing valve having a low-pressure set pressure. Compressed air supply system described in 1.   The compressed air supply source according to any one of claims 5 to 9, wherein a rated current of the air compressor is not more than half of a current capacity of an outlet for supplying power to the air compressor. system.   Compressed only in one direction from the inflow side connection portion to the outflow side connection portion, inserted into the inflow side connection portion and the outflow side connection portion, and the air flow path leading from the inflow side connection portion to the outflow side connection portion. An air plug having a check valve body portion for mounting a check valve body for flowing air, wherein each of the inflow side connection portion and the outflow side connection portion is formed in an air plug type connectable to an air socket. A check valve with an air plug.   An identification mark that can distinguish the inflow side connection portion and the outflow side connection portion in the form of an air plug, or an identification mark that can distinguish the direction of the air flow path from the inflow side connection portion to the outflow side connection portion. The check valve with an air plug according to claim 11, wherein the check valve is attached to a surface of the valve body portion. A check valve with an air plug for use in connecting at least the first and second air compressors in parallel, wherein the first air compressor supplies compressed air to an air tool. And when the second air compressor is used as a slave unit side for sending compressed air to the master unit side, between the air socket on the master unit side and the air socket on the slave unit side. Are connected by a check valve with an air plug, on the surface of the check valve body part is an arrow indicating the direction of compressed air flow, a mark indicating the master unit on the master unit connection side, or a slave unit on the slave unit connection side. The check valve with an air plug according to claim 12, wherein any one of marks indicating a machine is attached.

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