JP2789544B2 - Unloading device for reciprocating pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unloading device for a reciprocating pump provided in a washing machine or the like, and more particularly, to an unloading device having a simplified structure of a reciprocating pump.

[0002]

2. Description of the Related Art In a cleaning machine or a chemical sprayer, a nozzle which is opened and closed by operating a trigger is attached to a tip end of a spray hose, and is used to supply a cleaning liquid or a chemical solution which is pressure-fed from a power sprayer via the spray hose. It is designed to eject liquid. When the nozzle is closed, not only is the pumping of the cleaning liquid from the power sprayer unnecessary, but also the burden on the reciprocating pump of the power sprayer, so to prevent power loss,
The reciprocating pump is preferably unloaded (unloaded), and the power atomizer is equipped with an unloading device that puts the reciprocating pump in an unloaded state when the nozzle is closed.

A conventional unloading device (Japanese Utility Model Application Laid-Open No. 63-54)
No. 464 (FIG. 5) is provided on the discharge side of the reciprocating pump, and when the downstream side is closed, the discharge port of the reciprocating pump communicates with the liquid storage tank as an atmospheric pressure space.

[0004]

A conventional reciprocating pump in which the discharge side of the reciprocating pump communicates with the atmospheric pressure space to make the reciprocating pump unloaded requires a return line for returning the liquid to the tank, A switching valve structure for switching the discharge side of the reciprocating pump from the nozzle side to the tank side, or an on-off valve structure for opening and closing the return pipe is required separately from the reciprocating pump, which complicates the structure.

It is an object of the present invention to provide an unloading device for a reciprocating pump capable of simplifying the structure by omitting a liquid return line and a dedicated switching valve structure. It is an object of the present invention to provide an unloading device for a reciprocating pump which is incorporated in a reciprocating pump and can be reduced in size as a whole including the reciprocating pump.

[0006]

The present invention will be described with reference to the drawings corresponding to the embodiments. In the reciprocating pump (10) which is the premise of claim 1, the suction valve (26) and the discharge valve (40)
Are arranged on the suction side and the discharge side of the pump chamber (20), respectively. The unloading device for the reciprocating pump (10) according to claim 1 forcibly opens the suction valve (26) by receiving the water hammer pressure and the sealing pressure caused by the downstream side of the discharge valve (40) being closed. Operating members (56, 62).

[0007] In the unloading device for the reciprocating pump (10) according to the second aspect, the operating member (56, 62) is incorporated into the pump case (14) together with the suction valve (26) and the discharge valve (40), and the downstream. A piston (56) which is displaced against the urging member (60) by receiving a water hammer pressure and a sealing pressure accompanying the closing of the side, and a valve of the suction valve (26) which is displaced integrally with the piston (56). Valve (36) by contact with body (36)
And a piston rod (62) for forcing the piston to open.

[0008]

In the unloading device for a reciprocating pump (10) according to the first aspect, when a nozzle or the like connected downstream of the reciprocating pump (10) is in a closed state, the liquid discharged from the reciprocating pump (10) Blocked flow, large water hammer pressure reciprocating pump
It is transmitted to (10). As a result, the operation members (56, 62)
Operates by receiving the transmitted water hammer pressure and operates the suction valve (2
6) Force open. On the other hand, the downstream side of the discharge valve (40) becomes high pressure due to the closing of the nozzle and the like.
0) is closed, and the downstream side of the discharge valve (40) is sealed. The operating members (56, 62) hold the suction valve (26) in the open position even immediately after the closing of the nozzle or the like due to the sealing pressure.
As a result, the reciprocating pump (10) only sucks and discharges the liquid via the suction valve (26) held in the open state, and the operation becomes a no-load operation.

When the nozzle or the like is opened, the sealing is released on the downstream side of the discharge valve (40), and the pressure decreases, whereby the operating members (56, 62) are connected to the suction valve (26). The forcible opening is released, and the reciprocating pump (10) pumps the liquid.

In the unloading device for the reciprocating pump (10), when the nozzle or the like connected downstream of the reciprocating pump (10) is closed, the liquid discharged from the reciprocating pump (10) Blocked flow, large water hammer pressure reciprocating pump
It is transmitted to (10). As a result, the piston (56) receives the transmitted water hammer pressure and is displaced against the urging member (60), and the piston rod (62) is displaced integrally with the piston (56). Then, it comes into contact with the valve element (36) of the suction valve (26) to forcibly open the valve element (36). On the other hand, the discharge valve (40)
The downstream side has a high pressure, whereby the discharge valve (40) is closed and the downstream side of the discharge valve (40) is sealed. Due to this sealing pressure, the piston (56) holds the position displaced against the urging member (60) even immediately after closing the nozzle or the like, and the piston rod (62) holds the valve of the suction valve (26). The valve (36) is forced to open by contacting the body (36). As a result, the reciprocating pump (10) only sucks and discharges the liquid via the suction valve (26) held in the open state, and the operation becomes a no-load operation.

When the nozzle or the like is in the open position, the discharge valve (40)
On the downstream side, the seal is released and the pressure is reduced, whereby the piston (56) is displaced by the urging force of the urging member (60), and the piston rod (62) also moves the suction valve (26). Release the valve body (36) and release the forced opening of the valve body (36).
0) pumps the liquid.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a structural view of a multiple plunger pump 10 incorporating an unloading device. The multiple plunger pump 10 is mounted on a power sprayer such as a washer or a chemical sprayer. The crankcase 12 has a manifold 14
The plunger 16 extends in the crankcase 12 and the manifold 14, and reciprocates with rotation of a crankshaft (not shown) in the crankcase 12. The oil seal 18 is inserted into a penetrating portion of the plunger 16 on the tip side of the crankcase 12, and
The inside of the crankcase 12 is sealed against the reciprocating motion.

A pump chamber 20 is defined in the manifold 14 on the tip side of the plunger 16, and a seal packing 22 is
The pump chamber 20 is sealed against the sliding of the plunger 16 on the inner peripheral side. The suction port 24 is formed at a lower portion of the manifold 14, and the suction valve 26 is incorporated in the manifold 14 so as to be located between the pump chamber 20 and the suction port 24. The plug 28 is screwed to the manifold 14 to fix the suction valve 26 and prevent the suction valve 26 from coming off from the manifold 14. O-ring 30 is plug
It is sandwiched between the flange part of 28 and the manifold 14,
Sealing is performed. The suction valve 26 includes a valve seat 32 and a valve sack 34 with a through-hole, which are arranged on the downstream side and the upstream side, respectively, and are clamped together at a peripheral edge thereof.
A valve element 36 is disposed in the valve seat 32 and can be seated on the valve seat 32, and a compression coil spring 38 disposed in the valve sack 34 with a through hole and presses the valve element 36 against the valve seat 32. . The discharge valve 40 has its center line aligned with the center lines of the plunger 16 and the pump chamber 20,
The pump chamber 20 is incorporated into the manifold 14 at a position on the distal end side. The plug 42 is screwed to the manifold 14 to fix the discharge valve 40 and prevent the discharge valve 40 from coming off from the manifold 14. O-ring 44 is plug 42
Is sealed between the flange portion and the manifold 14 to perform sealing. The discharge valve 40 includes a valve seat 46 and a valve sack 48 with a through-hole, which are disposed on the downstream side and the upstream side, and are sandwiched together at the peripheral edge, and
And a compression coil spring 52 that is disposed in the valve sack 48 with through holes and presses the valve body 50 against the valve seat 46.

The assembling hole 54 is formed at a lower portion on the distal end side of the manifold 14 so that the center line thereof is aligned with the center line of the suction valve 26 and is opened at the distal end side of the manifold 14. In communication with The piston 56 is slidably inserted in the mounting hole 54 in the axial direction. Connection passage 58
Is formed in the piston 56, and communicates the peripheral portion of the piston 56 on the upstream side with the distal end surface on the downstream side, and communicates with the downstream side of the discharge valve 40 on the upstream side. The compression coil spring 60
The piston 56 is disposed further inside the mounting hole 54 than the piston 56, and biases the piston 56 toward the distal end of the manifold 14. The piston rod 62 is formed integrally with the piston 56,
It extends toward the suction valve 26 and can freely contact the valve body 36. The O-ring 64 is disposed on a partition wall of the manifold 14 through which the piston rod 62 penetrates, slides on the piston rod 62 on the inner peripheral side, and seals the space between the mounting hole 54 and the space on the suction valve 26 side. Are doing. The connection member 66 has a discharge port 68
Is screwed into the opening side of the mounting hole 54. The discharge port 68 communicates with the downstream side of the discharge valve 40 via the connection passage 58 of the piston 56. The spray hose (not shown) is connected to the connection member 66, and guides the liquid pumped from the pump chamber 20 via the discharge valve 40 to the nozzle on the distal end side. O-ring 70
Is sandwiched between the flange portion of the connection member 66 and the distal end surface of the manifold 14 to seal at the screw portion of the connection member 66 to the manifold 14. The piston 56 receives a force in the direction opposite to the urging force of the compression coil spring 60 from the hydraulic pressure on the discharge port 68 side, and the displacement to the discharge port 68 side is limited by contact with the end surface of the connecting member 66, and the suction valve The displacement to the 26 side is limited by the contact with the step 72 in the mounting hole 54.

The operation of the embodiment will be described. The plunger 16 reciprocates by rotating power sent from an engine (not shown) to increase or decrease the volume of the pump chamber 20.

When the nozzle attached to the tip end of the spray hose is open, the liquid is ejected from the nozzle, so that the liquid pressure downstream from the discharge valve 40 is low. The piston rod 62 is located at a position in contact with the end face of the connection member 66 by the urging force of the compression coil spring 60, and is separated from the valve element 36 of the suction valve 26. As a result, in the suction stroke of the plunger 16, the suction valve 26 and the discharge valve 40 are opened and closed, respectively, and the liquid is sucked into the pump chamber 20 from the suction port 24 through the suction valve 26, and the discharge of the plunger 16 is performed. In the stroke, the suction valve 26 and the discharge valve 40 are closed and opened, respectively, and the liquid in the discharge valve 40 is sent to the nozzle via the discharge valve 40, the connection passage 58 of the piston 56, and the discharge port 68.

When the nozzle is closed, the water hammer pressure is transmitted from the nozzle to the multiple plunger pump 10, and the liquid discharged from the discharge valve 40 is blocked from flowing.
The hydraulic pressure at increases. The piston 56 receives the water hammer pressure and is displaced toward the suction valve 26 against the compression coil spring 60 until the piston 56 comes into contact with the stepped portion 72. Accordingly, the piston rod 62
Contacts the valve body 36 of the suction valve 26, and forcibly separates the valve body 36 from the valve seat 32 against the compression coil spring 38. on the other hand,
The discharge valve 40 is closed in response to the increase in the hydraulic pressure on the downstream side,
As a result, the liquid is in a sealed state downstream of the discharge valve 40 and has a high pressure. Even after the water hammer pressure disappears, the piston 56 keeps the position in contact with the step 72 by the large sealing pressure, and the suction valve 26 is kept open while the nozzle is closed. Thus, with the reciprocation of the plunger 16, the liquid reciprocates between the suction port 24 and the pump chamber 20, and the multi-plunger pump 10 is operated without load.

Although the embodiment of the multiple plunger pump 10 has been described, the present invention is also applicable to a single plunger pump and a piston pump.

[0019]

According to the first aspect of the present invention, the reciprocating pump is switched to no load when the downstream side of the discharge valve is closed by the operation member forcibly setting the suction valve to the open position. Therefore,
A return line for returning the liquid to the tank during no-load operation of the reciprocating pump is not required, and a switching valve structure and an on-off valve structure separate from the reciprocating pump can be omitted, simplifying the structure of the unloading device. Can be planned.

According to the second aspect of the present invention, the operating member of the unloading device includes a piston which receives pressure from the downstream side downstream of the discharge valve and a valve body of the suction valve which is displaced integrally with the piston. Piston rod forcibly opening the valve body by contact, these pistons and piston rod,
Since the pump is incorporated into the pump case together with the suction valve and the discharge valve, the entire size including the reciprocating pump and the unloading device can be reduced.

[Brief description of the drawings]

FIG. 1 is a structural view of a multiple plunger pump incorporating an unloading device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Multiple plunger pump (reciprocating pump) 14 Manifold (pump case) 20 Pump chamber 26 Suction valve 36 Valve element 40 Discharge valve 56 Piston (operation member) 60 Compression coil spring (biasing member) 62 Piston rod (operation member)

Claims (2)

(57) [Claims] 1. A pump chamber (2) comprising a suction valve (26) and a discharge valve (40).
(0) Reciprocating pumps respectively arranged on the suction side and the discharge side
In (10), the suction valve (2) receives a water hammer pressure and a sealing pressure due to the downstream side of the discharge valve (40) being closed.
6. An unloading device for a reciprocating pump, comprising an operation member (56, 62) for forcibly opening 6). 2. The operating member (56, 62) is provided with a pump case.
(14) A piston which is incorporated together with the suction valve (26) and the discharge valve (40) and receives a water hammer pressure and a sealing pressure caused by closing the downstream side and displaces against a biasing member (60). (56), the valve body (36) of the suction valve (26) displaced integrally with the piston (56).
2. The unloading device for a reciprocating pump according to claim 1, further comprising a piston rod (62) for forcibly opening the valve body (36) by contact with the piston rod.