JP4169192B2 - Piston seal member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  In the present invention, for example, a piston such as a piston used in a quantitative filling nozzle device for weighing and filling a fluid by a predetermined amount is filled with a fluid such as a liquid or a viscous material.Each of outer cylinder and inner cylinderUsed to reciprocate against the cylinder wallAnnularWith respect to pistons, especially in such pistonseachTo be a sliding contact member with the cylinder wallAs an outer seal member and an inner seal memberAttachedeachThe present invention relates to the structure of a seal member.
[0002]
[Prior art]
  As for quantitative filling devices for weighing and filling fluids such as liquids and viscous materials by a predetermined amount, many devices of various structures have been proposed in various fields. For example, even a high-viscosity fluid mixed with solid materials such as curry or stew containing ingredients can be filled each time without clogging the solid matter in the nozzle passage. A quantitative filling nozzle for accurately weighing and filling accurately and quickly without leaving a weighed filling material has been proposed by the applicant of the present invention (Japanese Patent Laid-Open No. 2001-2001). No. 328605).
[0003]
  That is, in Japanese Patent Laid-Open No. 2001-328605, an inner cylinder having the same inner diameter as the discharge cylinder is provided between the upper end of the discharge cylinder and an outer cylinder having a small inner diameter discharge cylinder below the large inner diameter measurement cylinder. Are arranged concentrically on the inner side of the measuring cylinder (outer cylinder) with a predetermined interval between them, and the measuring cylinder (outer cylinder) is fixed to the outer cylinder and inner cylinder fixed to the bottom of the storage tank. The outer piston is slidably contacted with the inner surface of the inner cylinder and the outer surface of the inner cylinder, and the inner piston is movably moved vertically so as to be in slidable contact with the inner surface of the inner cylinder and the inner surface of the discharge cylinder. In addition, the lower part of the inner piston is a circle that can be closed between the inner cylinder and the discharge cylinder. The structure of a fixed-quantity filling nozzle is disclosed, which is formed in a continuous sealing plug portion, and a portion above the sealing plug portion of the inner piston is formed in a communication path portion having a space portion that is largely open to the outside. .
[0004]
[Problems to be solved by the invention]
  By the way, in the conventionally known quantitative filling nozzle device as described above, the annular piston (outer piston) provided between the outer cylinder (measuring cylinder) and the inner cylinder has an inner peripheral side wall surface of the inner cylinder. A space (outer cylinder and inner cylinder) filled with high-viscosity fluid mixed with solids in a state where the outer peripheral surface is in sliding contact with the outer peripheral surface and the outer peripheral side is in sliding contact with the wall surface (inner peripheral surface) of the outer cylinder. In such an annular piston, the sliding part on the inner peripheral side (inner cylinder side) and the outer peripheral side (outer cylinder side) ) Is required to have good slidability and good sealing properties so that fluid does not enter the gap between the piston and the cylinder wall surface. It is fit.
[0005]
  Therefore, in the past,3As shown in FIG. 2, the upper part of the piston 2 is arranged on the outer peripheral side (the outer cylinder 5 side) and the inner peripheral side (the inner cylinder 6 side) with respect to the main body portion of the annular piston (outer piston) 2. Each of the lower portions is provided with a sliding contact portion 50 formed by a combination of an elastic O-ring 51 and a slide ring 52 having a rectangular cross section excellent in slipperiness. In order to provide the sliding contact portion 50 in the main body portion of the piston 2 in such a combination, the main body portion of the piston 2 is divided into three members 2a, 2b, and 2c and assembled integrally by the bolts 13.
[0006]
  However, according to such a structure, when the apparatus is in use (during filling operation), the slide ring 52 is pressed against the wall surfaces of the cylinders 5 and 6 due to the elasticity of the O-ring 51. After use of the device (after completion of the filling operation), although not shown, the outer piston 2 is pulled up between a plurality of pins provided on the bottom wall of the tank, and the outer When the piston 2 is cleaned, the filling material (fluid) that has entered the gap between the sliding contact portions 50 to which the O-ring 51 and the slide ring 52 are attached is not easily removed in this cleaning process. Therefore, there is a concern that the remaining filling may cause a sanitary problem.
[0007]
  Various proposals have been made regarding the cleaning of the piston after use in the fixed-quantity filling device. For example, by using an O-ring and a slide ring as described in Japanese Patent Publication No. 7-1000048. In the case of a piston provided with a sliding contact portion, it is necessary to provide a cleaning passage inside the piston itself, which complicates the apparatus itself. For example, Japanese Patent Laid-Open No. 8-15199 In the case of a piston equipped with a sealing member (sealing member) made of a material that can be elastically deformed as described in the official gazette, the sealing member cannot be sufficiently sealed when the apparatus is used. There is a fear.
[0008]
  An object of the present invention is to solve the above-described problems, and a fluid is filled like a piston used in a nozzle device for quantitative filling.Between outer cylinder and inner cylinderUsed inAnnularPistoneachIt is an object of the present invention to provide a sealing member with good sealing properties and slidability when used, and to be able to clean well after use by spraying a cleaning liquid.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, the present inventionOuter cylinder and inner cylinder An annular piston provided betweenWhile the fluid is fulleachReciprocates against the cylinder wallEach of an outer seal member provided on the outer peripheral side of the annular piston and an inner seal member provided on the inner peripheral sideIn an annular shape made of a resin material capable of elastic deformationeachWith a seal member,eachThe part close to the sliding contact portion of the end surface of the seal member with the cylinder wall surface is exposed in the piston traveling direction so as to come into contact with the fluid.TheIn the exposed part of this end face, an annular groove is formed that opens in the direction of travel of the piston.In addition, the longitudinal cross-sectional shape of the annular groove of each seal member is the same shape and the same sizeIt is characterized by this.
[0010]
  According to the sealing member having the above structure,Each of the outer seal member provided on the outer peripheral side of the annular piston and the inner seal member provided on the inner peripheral sideIn use, the fluid is pushed into the annular groove as the piston advances, and the seal member is elastically deformed so as to expand the width of the annular groove. Is pressed against the side of the seal member to improve the sealing between the sliding contact portion of the seal member and the cylinder wall surface, and thereby fluid (filler, etc.) does not enter the gap between the seal member and the cylinder wall surface. Thus, the slidability can be maintained in a good state.
[0011]
  In addition, when the seal member is elastically deformed so that the width of the annular groove is widened in use, the joint surface between the piston main body portion and the seal member is more tightly adhered, so that the piston main body portion and the seal member are in close contact with each other. Since the fluid (filler or the like) can be prevented from entering the gap, the entire piston including the seal member can be cleaned well by spraying the cleaning liquid after use.
[0012]
  Further, since the annular grooves have the same shape and the same size in the outer seal member and the inner seal member, the operation of the annular piston provided between the outer cylinder and the inner cylinder is performed. Sometimes, the movement of the piston does not blur due to the difference in resistance force between the annular grooves of the outer seal member and the inner seal member.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of a sealing member for a piston of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the structure of the main part of a fixed-quantity filling nozzle device according to an embodiment of the present invention, and FIG. 2 shows an annular outer piston (including a seal member) of the device shown in FIG. The cross-sectional structure which ring-cuts the part (part without a bolt) is shown. Also figure3Shows the structure of the outer piston of the quantitative filling nozzle device for the conventional example,4And figure5These show the operating states of the quantitative filling nozzle device at each stage of filling (in use).
[0014]
  The piston equipped with the seal member of this embodiment is for measuring a predetermined amount of fluid food (such as curry or stew containing ingredients) mixed with solids and filling the cup container continuously. The fixed-quantity filling nozzle device is used in a fixed-quantity filling nozzle device, and is installed at the bottom of a tank in which fluid food serving as a filling material is stored. In addition, the filling of food into the cup container by this apparatus is defined, for example, in the aseptic filling line installed in a clean room (class 10,000 air cleanliness), particularly in a high level region of air cleanliness. In a clean booth (class 100 air cleanliness).
[0015]
  In such a quantitative filling nozzle device, as shown in FIG. 1, the piston sealing members of the present embodiment are respectively mounted on the outer peripheral side and the inner peripheral side of an annular outer piston 2 provided inside the device 1. Each of the outer seal member 3 and the inner seal member 4 has an annular outer piston 2 between a large-diameter cylindrical outer cylinder 5 and a small-diameter cylindrical inner cylinder 6 disposed concentrically. It is slidable in the vertical direction. In addition, although not shown in figure, the outer cylinder 5 and the inner cylinder 6 are fixedly installed with an appropriate coupling means with respect to the bottom of a tank for storing food to be filled.
[0016]
  A discharge cylinder having the same inner diameter as the inner cylinder 6 is provided at the lower end of the large-diameter cylindrical outer cylinder 5 through a bottom member 7 having an inverted conical inclined surface having an inclination angle of about 45 ° as an inner peripheral surface. 8 is integrally connected. Below the inner cylinder 6, a passage 9 is formed to allow a fluid as a filling to pass therethrough at a predetermined interval from the discharge cylinder 8. The annular outer piston 2 is in sliding contact with the inner peripheral surface of the outer cylinder 5 on its outer peripheral side, and is in sliding contact with the outer peripheral surface of the inner cylinder 6 on its inner peripheral side. It is formed in an inverted conical inclined surface that matches the inclined surface of the inner peripheral surface.
[0017]
  On the other hand, inside the inner cylinder 6, an inner piston 10 whose lower end portion is formed on the sealing plug portion 10 a so as to be in sliding contact with the inner peripheral surface of the inner cylinder 6 and the inner peripheral surface of the discharge cylinder 8 is slidable up and down. The lower part of the inner piston 10 is formed as a solid cylindrical sealing plug 10a, and the sealing plug 10a is provided between the inner cylinder 6 and the discharge cylinder 8. The passage 9 is formed in such a length that can be closed. A portion above the sealing plug portion 10a of the inner piston 10 is a communication path portion 10b having a space portion that is largely open to the outside in a state where only a part of the peripheral wall portion of the hollow cylindrical body is left as a support column. Is formed.
[0018]
  In addition, the outer piston 2 and the inner piston 10 which are the piston portions of the quantitative filling nozzle device are, for example, illustrated in FIG.4As shown to (A), it connects with the lower end of each of the outer rod 11 and the inner rod 12 which have penetrated the storage tank from the upper part so that attachment or detachment is possible, and it is driven up and down alternately at different timings. As the rods 11 and 12 move, they reciprocate up and down.
[0019]
  Although not shown, the fixed quantity filling nozzle device 1 having the above structure is installed at the bottom of a tank for storing a fluid food mixed with solid matter. Then, the food is constantly stirred so that the solid is not biased by reciprocating the stirring plate. Regarding the operating state of the above-mentioned quantitative filling nozzle device when filling the cup container with the fluid food in such a tank, FIG.4And figure5Will be described below.
[0020]
  In the fixed quantity filling nozzle device, the passage 9 between the inner cylinder 6 and the discharge cylinder 8 is sealed by the outer piston 2 in a state where both the outer piston 2 and the inner piston 10 are at the lower limit position, and the discharge cylinder 8 is sealed with the inner piston 10. The inside of the tank and the communication path portion 10b of the inner piston 10 are communicated with each other. From such a state, figure4As shown in (A), when the outer piston 2 rises as the outer rod 11 rises, the tank is driven by the suction force generated by the raising of the outer piston 2 until the outer piston 2 stops at the upper limit position. The food inside is forcibly introduced into the space (measuring chamber) between the outer cylinder 5 and the inner cylinder 6 through the passage 9 from the communication path portion 10 b of the inner piston 10.
[0021]
  Next, from the state where the outer piston 2 stops at the upper limit position, when the sealing plug portion 10a of the inner piston 10 rises as the inner rod 12 rises, the passage 9 above the discharge cylinder 8 is caused by the sealing plug portion 10a. After being temporarily closed, a predetermined amount of food is accurately weighed in the space between the outer cylinder 5 and the inner cylinder 6 (measuring chamber).4As shown in (B), the passage above the discharge cylinder 8 in a state where the inflow of food from the tank to the space (measuring chamber) between the outer cylinder 5 and the inner cylinder 6 is blocked by the sealing plug 10a. When 9 opens, only a predetermined amount of food measured in the space (measuring chamber) between the outer cylinder 5 and the inner cylinder 6 starts to drop downward through the discharge cylinder 8 and filling is started.
[0022]
  Then, from the state where the inner piston 10 is stopped at the upper limit position (the state where the inflow of food from the tank to the measurement chamber is blocked by the sealing plug portion 10a), FIG.5As shown in (C), when the outer piston 2 is lowered as the outer rod 11 is lowered, the food in the space (measuring chamber) between the outer cylinder 5 and the inner cylinder 6 is mixed with solid matter. Even a high-viscosity fluid is forced out of the space (metering chamber) between the outer cylinder 5 and the inner cylinder 6 by the outer piston 2 and is forced to drop downward through the discharge cylinder 8. Then, it is filled in a cup container (not shown) placed therebelow.
[0023]
  And figure5As shown in (D), when the inner piston 10 is lowered as the inner rod 12 is lowered from the state where the outer piston 2 is stopped at the lower limit position, a space (measurement) between the outer cylinder 5 and the inner cylinder 6 is measured. The food pushed out from the chamber) into the discharge cylinder 8 is forced out of the discharge cylinder 8 by the sealing plug portion 10a of the inner piston 10 and is forced into a cup container (not shown) placed therebelow. When the inner piston 10 is stopped at the lower limit position, the filling is completed once and the next filling is continuously performed.
[0024]
  According to the quantitative filling nozzle device that operates as described above, the object to be filled is provided by a simple mechanism in which the outer piston 2 and the inner piston 10 arranged concentrically are reciprocated up and down alternately at different timings. Even if the food to be used is a high-viscosity fluid mixed with solid matter, the filling amount is accurately measured each time without clogging the solid matter in the nozzle passage. It is possible to fill continuously accurately and quickly without leaving in the nozzle.
[0025]
  By the way, in the fixed quantity filling nozzle device that operates as described above, in this embodiment, as shown in FIG. 1, the annular outer piston 2 provided between the outer cylinder 5 and the inner cylinder 6 has a main body portion. The upper member 2a and the lower member 2b are divided into two members, and both members are integrally connected by a bolt 13 (a bolt member and a bolt portion formed at the lower end of the piston rod). In order to improve the liquid tightness of the joint surface between the base and the upper end surface of the outer piston 2 (upper member 2a), a ring seal 14 is interposed between the bolt 13 and the outer piston 2 (upper member 2a). Yes. An outer seal member 3 slidably in contact with the inner peripheral surface of the outer cylinder 5 is attached to the outer peripheral side of the main body portion of the outer piston 2, and the inner cylinder is connected to the inner peripheral side thereof. An inner seal member 4 slidably in contact with the outer peripheral surface of 6 is mounted.
[0026]
  The outer piston 2 having the outer seal member 3 and the inner seal member 4 mounted thereon will be described in more detail. In this embodiment, as shown in FIG. 2, the upper member 2a and the lower member 2b of the outer piston 2 In order to improve liquid-tightness, the joint surface is stepped in steps. In addition, an annular concave portion 21 whose outer side is opened on the outer peripheral surface of the outer piston 2 so that the longitudinal section is a vertically long U-shape so as to straddle the joint surface between the upper member 2a and the lower member 2b. Are formed on the outer peripheral ends of the upper and lower ends of the outer recess 21 so as to protrude in the vertical direction inside the outer recess 21 (that is, in the axial direction of the piston). 22 and 22 are formed, respectively.
[0027]
  And with respect to such an outer piston 2, an annular outer seal member 3 made of a resin material capable of elastic deformation is fitted into the outer recess 21 with substantially half of its inner peripheral side, and its upper end surface It is mounted on the outer peripheral side of the outer piston 2 with the locking projections 22, 22 biting into the lower end surface. That is, approximately half of the inner peripheral side of the outer seal member 3 is fitted in close contact with the wall surface of the outer recess 21 while being liquid-tightly cut off from the outside by the locking projections 22 and 22. It has become.
[0028]
  In the present embodiment, the line connecting the vertices of the locking protrusions 22, 22 of the upper member 2a and the lower member 2b of the outer piston 2 is made to coincide with the axial direction of the outer piston 2, While the outer piston 2 is in operation, no rotational moment is generated in the outer seal member 3 with any of the upper and lower locking projections 22 as a fulcrum, and the main body of the outer piston 2 is generated by the generation of such rotational moment. The liquid tightness between the portion (the upper member 2a and the lower member 2b) and the outer seal member 3 is not impaired.
[0029]
  In the outer half of the outer seal member 3 that is mounted on the outer piston 2 as described above (on the part protruding from the outer recess 21), the outer peripheral surface includes cylinder wall surfaces ( Ring-shaped sliding contact projections 31, 31 projecting in a mountain shape toward the inner peripheral surface of the outer cylinder 5 are formed, and portions between the upper and lower sliding contact projections 31, 31 projecting in a mountain shape Has a cylindrical outer surface shape, and the annular crest portions of the sliding contact projections 31, 31 protruding in a mountain shape are in sliding contact with the cylinder wall surface (inner peripheral surface of the outer cylinder 5). Such a sliding contact portion.
[0030]
  In addition, in the substantially half of the outer seal side of the outer seal member 3 (the part protruding from the outer recess 21), the upper and lower end surfaces of the outer seal member 3 are open toward the traveling direction (upward or downward) of the outer piston 2. As described above, annular grooves 32 and 32 having a U-shaped longitudinal section (or may be V-shaped) are formed. The depths of the annular grooves 32, 32 having a U-shaped longitudinal section are substantially corresponding to the vertical lengths of the annular sliding contact protrusions 31, 31 protruding in a mountain shape. Each of the upper and lower sliding projections 31 and 31 has the same shape and size, and each of the upper and lower annular grooves 32 and 32 has the same shape and depth.
[0031]
  The outer seal member 3 mounted on the outer peripheral side of the outer piston 2 is as described above, but the inner seal member 4 mounted on the inner peripheral side of the outer piston 2 is Compared to the case, the relationship between the inner side (inner peripheral side) and the outer side (outer peripheral side) is reversed, the thickness (width) of the member 4 and the ring diameter are different, and each of the sliding contact projections 41, 41 and each annular groove Although the ring diameters of 42 and 42 are different, the material, the basic longitudinal sectional shape, and the mounting structure to the outer piston 2 are the same as in the case of the outer seal member 3, so the detailed description of the inner seal member 4 Is omitted.
[0032]
  In the outer piston 2 to which the outer seal member 3 and the inner seal member 4 are mounted as described above, when the outer piston 2 moves downward during the operation, the outer seal member 3 and the inner seal member 4 On the respective lower end sides, the fluids (fillers) are pushed into the respective annular grooves 32, 42, and the respective seal members 3, 4 are elastic so that the widths of the respective annular grooves 32, 42 are increased accordingly. By deforming, the lower sliding contact projections (annular projections protruding in a mountain shape) 31 and 41 which are the sliding contact portions near the lower ends of the seal members 3 and 4 are respectively connected to the cylinder wall surfaces (outer cylinders 5). The outer peripheral surface of the inner cylinder 6 and the outer peripheral surface of the inner cylinder 6 are pressed against each other, and the joint surface between the lower member 2b of the outer piston 2 and each of the seal members 3 and 4 is its outlet. And thus it is in close contact more strongly in the near (near the locking projection 22).
[0033]
  On the other hand, when the outer piston 2 moves upward, a fluid (filler) is formed in the annular grooves 32 and 42 at the upper ends of the outer seal member 3 and the inner seal member 4. When the seal members 3 and 4 are elastically deformed so that the widths of the respective annular grooves 32 and 42 are expanded as they are pushed in, the upper annular shape which is a sliding contact portion near the upper ends of the seal members 3 and 4. The protrusions (annular protrusions protruding in a mountain shape) 31 and 41 are pressed against the respective cylinder wall surfaces (the inner peripheral surface of the outer cylinder 5 and the outer peripheral surface of the inner cylinder 6), and the upper member 2a of the outer piston and each seal member The joint surface with 3 and 4 is more closely attached in the vicinity of the exit (near the locking projection 22).
[0034]
  Further, although the upper and lower annular grooves 32 and 32 of the outer seal member 3 and the upper and lower annular grooves 42 and 42 of the inner seal member 4 have different ring diameters, the longitudinal sectional shape (U-shape) of the grooves is different. Since the same shape and the same size, the movement of the outer piston 2 is shaken due to the difference in resistance force between the annular grooves 32 and 42 of the outer seal member 3 and the inner seal member 4 when the apparatus is operated. There is nothing to wake up.
[0035]
  According to the seal members (outer seal member 3 and inner seal member 4) of the present embodiment that are elastically deformed during operation as described above, when the outer piston 2 reciprocates in the vertical direction, it proceeds in any direction. Even when doing so, the sliding members 31, 4 of the sealing members 3, 4 are always elastically deformed so that the width of the annular grooves 32, 42 is expanded on the side in the traveling direction. As a result, the fluidity (filler) does not enter the gaps between the outer piston 2 and the wall surfaces of the cylinders 5 and 6, so that the slidability of the outer piston 2 is improved. Can always be maintained well, and the fluid (fill) is pushed out by the outer piston 2 without leaking the fluid (fill) from the gap between the wall surfaces of the cylinders 5 and 6. Loading body (packing) and (extrusion rate) can be made variations always without accurate.
[0036]
  Further, each seal member 3, 4 is elastically deformed so as to expand the width of the respective annular grooves 32, 42, whereby the main body portion (upper member 2 a or lower member 2 b) of the outer piston 2 and each seal member 3, 4. Since the fluid interface (filler) does not enter the gap between the main body portions 2a and 2b of the outer piston 2 and the seal members 3 and 4, as a result, When the outer piston 2 is cleaned by spraying cleaning liquid after use, the fluid (filler) is left in the gaps between the main body portions 2a, 2b of the outer piston 2 and the seal members 3, 4. In addition, the entire outer piston 2 including the seal members 3 and 4 can be satisfactorily cleaned by spraying a cleaning liquid or the like.
[0037]
  Furthermore, since the longitudinal cross-sectional shape of each annular groove 32 and 42 of each seal member 3 and 4 is the same shape and the same magnitude | size, when the outer piston 2 act | operates, each of the outer seal member 3 and the inner seal member 4 is each The movement of the outer piston 2 is not blurred due to the difference in resistance force caused by the annular grooves 32 and 42.
[0038]
  For the quantitative filling nozzle device 1 using the outer piston 2 fitted with the outer seal member 3 and the inner seal member 4 as described above, after the vegetable soup is quantitatively filled into the plastic cup over 8 hours, the outer piston 2 Is pulled out from between the outer cylinder 5 and the inner cylinder 6 and supported by a plurality of pins (not shown) standing on the bottom of the tank above the outer cylinder 5 at 80 ° C. and 2% caustic soda water. After spraying and cleaning, no residual deposits were found and the cleanability was good. In addition, the cleaning performance was also good by the cleaning method in which the cleaning liquid was sprayed up and down and reciprocated up and down between the outer cylinder 5 and the inner cylinder 6.
[0039]
  As mentioned above, although one embodiment of the sealing member of the piston of the present invention was described, the present invention is not limited only to the specific structure shown in the above embodiment. The seal member 3 and the inner seal member 4 are each formed as one member. However, the present invention is not limited to such a structure, and the outer seal member 3 and the inner seal member 4 are formed as two members each. It is also possible to implementAnd alsoNozzle device for quantitative filling as shown in the above embodimentNot onlyUsed for other equipmentthingAs for the specific structure of the seal member itself, for example, the cross-sectional shape of the annular groove is not limited to the U-shaped or V-shaped annular groove, and the fluid is annular. Needless to say, the design can be changed as appropriate as long as the seal member is elastically deformed so as to expand the width of the groove by being pushed into the groove.
[0040]
【The invention's effect】
  According to the piston sealing member of the present invention as described above, in use, the sliding contact portion of the sealing member is pressed against the cylinder wall surface side by elastically deforming the sealing member so as to widen the annular groove. For this reason, the sealing property at the sliding contact portion of the seal member is improved, and the fluid does not enter the gap between the seal member and the cylinder wall surface, so that the slidability can be maintained in a good state. In addition, due to the elastic deformation of the seal member, the joint surface between the main body portion of the piston and the seal member is more closely adhered, and the fluid does not enter the gap between the main body portion of the piston and the seal member. The entire piston including the seal member can be cleaned well by spraying cleaning liquid or the like.Further, since the longitudinal sectional shape of each annular groove of each seal member is the same shape and the same size, each annular shape of each seal member is activated when the annular piston provided between the outer cylinder and the inner cylinder is operated. There is no blurring of the piston movement due to the difference in resistance caused by the groove.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a structure of a main part of a quantitative filling nozzle device in which a seal member is used in an embodiment of a piston seal member of the present invention.
2 is a longitudinal sectional view showing a structure of a cut end face obtained by ring-cutting an annular part (a part without a bolt) of an outer piston (including a seal member) of the apparatus shown in FIG. 1;
[Figure3A longitudinal sectional view showing a structure of an outer piston of a nozzle device for quantitative filling in a conventional example.
[Figure4An explanatory view of a longitudinal section showing an operating state in each stage (A), (B) at the time of filling by the nozzle device for constant filling.
[Figure5] Drawing when filling with nozzle device4FIG. 4 is a longitudinal cross-sectional explanatory view showing an operation state in each stage (C), (D) following (A), (B).
[Explanation of symbols]
  1 Nozzle device for quantitative filling
  2 Outer piston
  3 Outer seal member
  4 Inner seal member
  5 Outer cylinder
  6 Inner cylinder
  31 Sliding contact projection (sliding contact portion with cylinder wall surface)
  32 annular groove
  33 Cylindrical surface (sliding contact with cylinder wall surface)
  41 Sliding contact projection (sliding contact part with cylinder wall surface)
  42 Annular groove
  43 Cylindrical surface (sliding contact part with cylinder wall surface)

Claims (6)

An annular piston provided between the outer cylinder and the inner cylinder, and an outer seal member and an inner circumference provided on the outer peripheral side of the annular piston that reciprocates with respect to the wall surface of each cylinder while the fluid is full in each of the inner seal member provided on the side, each seal annular member made of a resin material capable of elastic deformation, a portion close to the sliding contact portion between the cylinder wall of the end faces of the sealing member is in contact with the fluid in it is exposed in the traveling direction of the piston as the exposed portion of the end face, an annular groove open toward the advancing direction of the piston is formed, the longitudinal sectional shape of the annular groove of the seal members, the same A piston sealing member having the same size in shape . 2. The seal member according to claim 1, wherein each seal member exposes a portion close to a sliding contact portion with the cylinder wall surface at both end faces, and annular grooves are formed on both end faces of the seal member, respectively. Piston seal member. 2. The seal member according to claim 1, wherein each seal member exposes a portion close to a sliding contact portion with the cylinder wall surface at one end face thereof, and an annular groove is formed on one end face of the seal member. Piston seal member. 3. The piston seal according to claim 1, wherein the sliding contact portion of each seal member with the cylinder wall surface is formed as an annular sliding contact protrusion protruding in a mountain shape toward the cylinder wall surface. 4. Element. The piston sealing member according to claim 1 or 2, wherein a sliding contact portion of each sealing member with a cylinder wall surface is formed as a cylindrical surface slidingly contacting the cylinder wall surface. Piston, the piston seal member according to any one of claims 1 to 5 characterized in that it also is so used in the nozzle device for quantitative filling.

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