JP5068344B2 - pump - Google Patents

Description

  The present invention relates to a pump used for fluid transfer in research of chemicals and pharmaceuticals.

  Conventionally, a pump called a micropump has been used as a pump for transferring a liquid such as a chemical in research and analysis of chemicals and pharmaceuticals.

  In this type of pump, a piston is provided so as to be able to reciprocate with respect to the pump chamber, and when the piston reciprocates, a certain amount of liquid drawn into the pump chamber from the liquid suction channel is transferred to the liquid discharge channel. There are some which send out intermittently (see, for example, Patent Documents 1 and 2). And in this pump, the sliding location of the piston with respect to a pump chamber is sealed with the sealing member.

Japanese Patent Laid-Open No. 10-238475 JP 2008-255805 A

  By the way, in the above pump, the pressure in the pump chamber may fluctuate in the liquid suction / discharge process, and the seal member in contact with the liquid in the pump chamber may be deformed, and the sliding resistance between the seal member and the piston may However, the seal member may be slightly deformed. When the seal member is deformed in this way, the volume in the pump chamber varies with the deformation.

  In particular, when a seal member of a type that expands due to the hydraulic pressure in the pump chamber and increases the sealing force with the piston is used as the seal member, the seal member is also greatly deformed by the pressure variation in the pump chamber, and the volume variation in the pump chamber also increases. .

  In this way, when the volume of the pump chamber fluctuates in the suction / discharge process, the accuracy of the liquid discharge rate from the pump decreases, and chemicals and pharmaceuticals for which accurate management of the discharge rate is an absolute requirement As a result, the pump is not suitable for use in research or analysis.

  The present invention has been made in view of the above circumstances, and can inhale and discharge a fluid with extremely high accuracy, and in research and analysis of chemicals and pharmaceuticals, etc., for which management of a high accuracy discharge amount is an absolute condition. It is intended to provide a pump that is suitable for use.

To achieve the above object, the pump of the present invention, a cylinder liquid inlet passage and liquid discharge passage have a pump chamber which communicates with intake port and the discharge port is formed,
A frame member joined to the rear end side of the cylinder;
A joining screw for fastening the cylinder and the frame member in a state in which the joining surfaces are in contact with each other;
A piston that is spaced from the inner surface of the cylinder and the inner surface of the frame member, connected to a moving mechanism provided on the rear end side of the frame member, and supported so as to be reciprocally movable;
A seal part that seals the gap between the cylinder and the frame member and the piston to define the pump chamber;
The exposed surface exposed to the pump chamber of the seal portion, is non positive displacement guaranteed surface deformation in the inner pressure of the pump chamber, and,
The seal portion, the piston sliding hole is slidably inserted, the distance from the sliding hole in the plane outwardly of the previous SL exposed surface open to the surface of the opposite side in the opposite surface A first member having an annular groove formed between the sliding hole and the annular groove, and an opening of the annular groove with respect to the first member. A second member mounted on the side and having a sliding hole through which the piston is slidably inserted ,
By fastening the joining screw, the annular elastic member disposed in the annular groove is deformed so as to be crushed in the axial direction and spread in the radial direction, whereby the cylindrical seal plate portion is radially moved from the elastic member. The inner peripheral surface of the sliding hole of the first member is pressed against the outer peripheral surface of the piston by receiving an inward pressing force and the repulsive force of the elastic member crushed in the axial direction is The first member and the second member act in a direction away from each other, and the first member is pressed against the cylinder .

  According to the pump having such a configuration, the exposed surface of the seal portion exposed to the pump chamber is not deformed by the internal pressure of the pump chamber, so that the pressure in the pump chamber fluctuates by transferring the fluid by reciprocating the piston. In addition, volume fluctuation due to deformation is suppressed. Thereby, the fluid can be sucked and discharged with extremely high accuracy. That is, this pump is suitable for use in research and analysis of chemicals and pharmaceuticals, for which high-accuracy discharge rate management is an absolute condition. Further, compared with a structure in which sealing is directly performed by a sealing member such as rubber, the liquid resistance is excellent, deterioration due to repeated deformation can be suppressed, and a long life can be achieved.

According to the pump having such a configuration, when the annular elastic member is pushed into the annular groove of the first member, the cylindrical seal plate portion is deformed radially inward by the elastic force of the elastic member, and the inner peripheral surface of the sliding hole. Is pressed against the outer peripheral surface of the piston, so that the gap between the cylinder and the piston can be reliably sealed. In addition, the thickness dimension of a cylindrical seal board part can be set to 0.1-1.0 mm, for example.

In particular, by attaching the second member to the first member and forcibly pushing the elastic member into the annular groove, it is very easy to press the cylindrical seal plate portion by the elastic member and to improve the cylinder and piston by the seal portion. A good sealing state. Further, the coaxiality of the piston with respect to the cylinder can be ensured by forming the sliding holes and the pistons of the first member and the second member with high fitting dimensional tolerances.

  In the pump of the present invention, the first member may be mounted with the second member in which an annular facing surface facing the annular groove is a convex surface, a flat surface, or a concave surface.

  According to the pump having such a configuration, by selectively using the second member having a different shape of the annular facing surface facing the annular groove of the first member, the elastic force of the elastic member can be set according to the internal pressure of the pump chamber. Can be controlled. For example, when the internal pressure of the pump chamber is high and a high sealing force is required, a second member having a convex annular surface facing the annular groove of the first member is used, the internal pressure of the pump chamber is low, and the sealing force is low. When the lower member may be low, the second member having a concave surface facing the annular groove of the first member is used, and when an intermediate sealing force is required, the annular member facing the annular groove of the first member is used. A second member having a flat bearing surface is used.

  According to the pump of the present invention, fluid can be sucked and discharged with extremely high accuracy, and it is suitable for use in research and analysis of chemicals and pharmaceuticals, etc., for which high-accuracy discharge amount management is an absolute condition. can do.

It is a figure explaining the structure of the pump which concerns on embodiment of this invention, Comprising: (a) is a front view, (b) is AA sectional drawing in (a). It is BB sectional drawing in FIG.1 (b). It is a figure which shows the 1st member provided in a pump, Comprising: (a) is sectional drawing, (b) is a front view. It is a figure which shows the 2nd member provided in a pump, Comprising: (a) is a front view, (b) is sectional drawing. It is a figure explaining the other example of a 2nd member, Comprising: (a) And (b) is sectional drawing of a part of 2nd member, respectively. It is sectional drawing explaining the 2nd member of another structure. It is sectional drawing explaining the 1st member of another structure.

DESCRIPTION OF SYMBOLS 11 Pump 12 Cylinder 14 Pump chamber 16 Intake flow path 18 Discharge flow path 31 1st member 31b Volume ensuring surface 32 Sliding hole 33 Annular groove 34 Cylindrical seal board part 41 2nd member 43 Annular protrusion (convex surface)
44 Annular recess (concave surface)
51 piston 55 elastic ring (elastic member)

  Hereinafter, embodiments of a pump according to the present invention will be described with reference to the drawings.

  1A and 1B are diagrams illustrating the structure of a pump according to an embodiment of the present invention, in which FIG. 1A is a front view, FIG. 1B is a cross-sectional view taken along line AA in FIG. FIG. 3 is a diagram showing a first member provided in the pump, wherein (a) is a sectional view, (b) is a front view, and FIG. 4 is a second member provided in the pump. It is a figure, (a) is a front view, (b) is sectional drawing.

  As shown in FIGS. 1 and 2, the pump 11 of the present embodiment has a cylinder 12, and a frame member 13 is joined to the rear end side of the cylinder 12 (the right side in FIG. 1). Yes.

  The cylinder 12 is made of a resin material having excellent chemical resistance such as acrylic, and a pump chamber 14 having a tapered tip is formed in the center along the axial direction. . A suction port 15 is formed on the side of the cylinder 12, and the suction port 15 and the side of the pump chamber 14 communicate with each other via a suction flow path 16. A discharge port 17 is formed at the tip of the cylinder 12, and the discharge port 17 and the tip of the pump chamber 14 are communicated with each other via a discharge channel 18.

  Further, a concave portion 21 having a circular shape in plan view is formed on the rear end surface (hereinafter referred to as a joint surface 12a) of the cylinder 12 to which the front end surface of the frame member 13 is joined, and the bottom of the pump chamber 14 is formed on the bottom surface 21a of the concave portion 21. The rear end side is open.

  Further, screw insertion holes 22 are formed in the cylinder 12 in the vicinity of the four corners in plan view, and a joining screw 23 is inserted into these screw insertion holes 22 from the front end side of the cylinder 12.

  The frame member 13 joined to the cylinder 12 is made of a resin material having excellent chemical resistance such as acrylic, and an insertion hole 25 is formed at the center thereof. The frame member 13 is formed with a circular recess 26 in a plan view on a tip surface (hereinafter referred to as a “joint surface 13 a”) to which the joint surface 12 a of the cylinder 12 is joined, and the insertion hole 25 is formed in the bottom surface 26 a of the recess 26. Is open.

  Screw holes 27 are formed in the frame member 13 in the vicinity of the four corners of the joint surface 13a, and the joint screws inserted into the screw insertion holes 22 from the tip end side of the cylinder 12 into these screw holes 27. 23 is screwed. Thereby, the cylinder 12 and the frame member 13 are joined in a state in which the joining surfaces 12 a and 13 a are in contact with each other by the fastening force of the joining screw 23 to the screw hole 27.

  Thus, by accommodating the cylinder 12 and the frame member 13, the accommodation space 30 is formed in the pump 11 from the recess 21 of the cylinder 12 and the recess 26 of the frame member 13. The housing space 30 houses a first member 31 and a second member 41 as constituent members of a seal portion that seals the gap between the inner surface of the cylinder 12 and the piston 51 to define the pump chamber 14. ing. The first member 31 is formed in an annular shape that can be fitted into the recesses 21 and 26. A second member 41 is attached to the first member 31 on the frame member 13 side, and the second member 41 is also accommodated in the accommodating space 30.

  The first member 31 and the second member 41 have sliding holes 32 and 42 communicating with each other, and the piston 51 is slidably inserted into the communicating sliding holes 32 and 42. . The piston 51 is made of an inorganic material having excellent chemical resistance, such as hard glass, and its tip is disposed in the pump chamber 14 of the cylinder 12. The rear end of the piston 51 is passed through the insertion hole 25 of the frame member 13 and connected to a moving mechanism (not shown) provided on the rear end side of the frame member 13. The piston 51 is moved by the moving mechanism in a suction direction (in the direction of arrow α in FIG. 1) that moves toward the frame member 13 and in a discharge direction (in the direction of arrow β in FIG. 1) that moves toward the cylinder 12.

  The sliding holes 32, 42 and the pistons 51 inserted through these sliding holes 32, 42 are formed with a smaller diameter than the pump chamber 14 of the cylinder 12 and the insertion holes 25 of the frame member 13. As a result, a gap is formed between the outer peripheral surface of the piston 51 and the inner peripheral surface of the pump chamber 14 on the cylinder 12 side, and the outer peripheral surface of the piston 51 and the inner periphery of the insertion hole 25 on the frame member 13 side. A gap is formed between the surface.

  The first member 31 is formed of a hard resin material having excellent chemical resistance against the liquid to be transferred, such as high molecular polyethylene resin, polytetrafluoroethylene resin, and the like. Manufactured by molding.

  The sliding hole 32 of the first member 31 has a dimensional tolerance of a fitting hole of about M6, M7 (JIS B 0401), for example, with respect to the piston 51. The sliding hole 32 is inserted into a state having an appropriate sliding resistance without rattling.

  The close contact surface 31a of the first member 31 on the pump chamber 14 side and the bottom surface 21a of the recess 21 of the cylinder 12 with which the close contact surface 31a comes into contact are each a smooth surface. 31 a is liquid-tightly attached to the bottom surface 21 a of the recess 21 of the cylinder 12.

  A part of the close contact surface 31 a on the pump chamber 14 side of the first member 31 is exposed to the pump chamber 14. The exposed surface of the first member 31 exposed to the pump chamber 14 is not deformed by the internal pressure of the pump chamber 14 because the first member 31 is made of a hard resin material. That is, the exposed surface of the first member 31 in the pump chamber 14 is a volume ensuring surface 31b that is a surface that does not cause a volume fluctuation in the pump chamber 14.

  In addition, as shown in FIG. 3, the first member 31 has an annular groove 33 formed on the contact surface 31 c side with the second member 41. The annular groove 33 is formed in the vicinity of the sliding hole 32 (a position spaced apart from the sliding hole 32 in the surface direction (outer peripheral side) by a predetermined interval). A cylindrical seal plate portion 34 formed in a thin plate shape is formed between the groove 33 and the circumferential direction. The cylindrical seal plate portion 34 has a thickness dimension of, for example, about 0.1 to 1.0 mm, and can be easily elastically deformed by an external force acting in the thickness direction.

  The second member 41 is manufactured by, for example, injection molding or processing molding a resin material having a low friction coefficient and excellent wear resistance, such as nylon or polyacetal.

  The sliding hole 42 of the second member 41 has a dimensional tolerance of a fitting hole of about H7 (JIS B 0401), for example, with respect to the piston 51. The slide hole 42 is slidably inserted.

  Further, as shown in FIG. 4, the second member 41 has an annular facing surface facing the annular groove 33 of the first member 31 on the contact surface 41 a side with the first member 31. It is said that. The annular protrusion 43 is formed at a position facing the annular groove 33 of the first member 31. By overlapping the first member 31 and the second member 41 in the axial direction, the annular groove of the first member 31 is formed. Enter 33.

  An elastic ring (elastic member) 55 is disposed in the annular groove 33 of the first member 31. The elastic ring 55 is formed in a circular cross section, and its diameter is substantially the same as the width of the annular groove 33 of the first member 31. The elastic ring 55 is manufactured by, for example, injection molding or processing molding an elastic material such as rubber or a resin such as elastomer having high resilience. As the elastic ring 55, a commercially available O-ring or the like can be used.

  The elastic ring 55 disposed in the annular groove 33 of the first member 31 is pressed toward the bottom side of the annular groove 33 by the annular protrusion 43 of the second member 41 and is elastically deformed so as to spread in the radial direction. ing.

  As a result, the cylindrical seal plate portion 34 of the first member 31 receives a pressing force directed radially inward by the elastic force from the elastic ring 55 and is deformed to the piston 51 side. Therefore, the inner peripheral surface that defines the sliding hole 32 of the first member 31 is pressed against the outer peripheral surface of the piston 51, and extremely high sealing performance is ensured between the first member 31 and the piston 51.

  Further, the first member 31 and the second member 41 are pressed in directions away from each other by the repulsive force of the deformed elastic ring 55. Thereby, since the contact surface 31 a of the first member 31 is strongly pressed against the bottom surface 21 a of the concave portion 21 of the cylinder 12, extremely high sealing performance is ensured between the cylinder 12 and the first member 31.

  In the pump 11 having the above structure, the suction port 15 and the discharge port 17 are connected to the suction pipe and the discharge pipe, respectively, so that the suction pipe 16 and the pump chamber 14 and the discharge flow path 18 discharge from the suction pipe. A flow path capable of feeding liquid to the pipe is formed. The suction pipe and the discharge pipe are each provided with a check valve, and the liquid feeding direction is sucked in the flow path composed of the suction pipe, the suction flow path 16, the pump chamber 14, the discharge flow path 18 and the discharge pipe. It is restricted to one direction that flows from the pipe side to the discharge pipe side.

  In this state, when the piston 51 of the pump 11 moves in the suction direction (arrow α direction in FIG. 1), the piston 51 is pulled out from the pump chamber 14 by the amount of the movement, and the inside of the pump chamber 14 becomes negative pressure. As a result, a volume of liquid corresponding to the volume of the part from which the piston 51 is pulled out is sucked into the pump chamber 14 from the suction pipe via the suction flow path 16.

  Next, when the piston 51 of the pump 11 moves in the discharge direction (arrow β direction in FIG. 1), the tip end side of the piston 51 is pushed out to the pump chamber 14 by the amount of the movement, and the inside of the pump chamber 14 becomes positive pressure. A liquid having a volume corresponding to the volume of the portion where is pushed out is discharged from the pump chamber 14 to the discharge pipe via the discharge flow path 18.

  Thus, in the pump 11, by reciprocating the piston 51, the liquid is sucked and discharged, and a predetermined amount of liquid is fed.

  Here, according to the pump 11, the exposed surface exposed to the pump chamber 14 of the cylinder 12 of the first member 31 that seals the cylinder 12 and the piston 51 is not deformed by the internal pressure of the pump chamber 14. Therefore, even if the pressure in the pump chamber 14 fluctuates by moving the piston 51 back and forth, the volume fluctuation due to deformation is suppressed. Thereby, the liquid can be sucked and discharged with extremely high accuracy.

  In other words, the pump 11 is suitable for use in research and analysis of chemicals and pharmaceuticals, for which high-accuracy discharge amount management is an absolute condition. Further, compared with a structure in which sealing is directly performed by a sealing member such as rubber, the liquid resistance is excellent, deterioration due to repeated deformation can be suppressed, and a long life can be achieved.

  Further, when the annular elastic ring 55 is pushed into the annular groove 33 of the first member 31, the cylindrical seal plate portion 34 is deformed radially inward by the elastic force of the elastic ring 55, and the inner peripheral surface of the sliding hole 32. Is pressed against the outer peripheral surface of the piston 51, so that the space between the first member 31 and the piston 51 can be reliably sealed. At this time, the contact surface 31 a of the first member 31 is pressed against the bottom surface 21 a of the recess 21 of the cylinder 12 by the elastic force of the elastic ring 55, so that an extremely high seal is provided between the cylinder 12 and the first member 31. Sex can be secured.

  Further, the second member 41 is mounted on the first member 31 so as to be overlapped in the axial direction, and the elastic ring 55 is pushed into the annular groove 33 so that the elastic ring 55 is pressed very easily. A good sealing state between the cylinder 12 and the piston 51 by the first member 31 can be secured by the elastic force.

  Further, by forming the sliding hole 42 of the second member 41 and the piston 51 with a high fitting dimensional tolerance, the coaxiality between the piston 51 and the cylinder 12 can be ensured.

  In the above embodiment, the second member 41 in which the convex surface of the annular protrusion 43 is formed on the annular facing surface facing the annular groove 33 of the first member 31 is attached to the first member 31. As shown in FIG. 5 (a), 41 has an annular facing surface opposed to the annular groove 33 of the first member 31 as a flat bearing surface, or as shown in FIG. What formed the concave surface which has the recessed part 44 can be used selectively.

  In this way, by selectively using the second member 41 having a different shape of the annular facing surface facing the annular groove 33 of the first member 31, the elastic force generated in the elastic ring 55 can be generated by the internal pressure of the pump chamber 14. Can be controlled accordingly. For example, when the internal pressure of the pump chamber 14 is high and a high sealing force is required, the second member 41 having the annular protrusion 43 is used. When the internal pressure of the pump chamber 14 is low and the sealing force may be low, the annular recess 44 is used. When the second member 41 having the intermediate pressure is required and an intermediate sealing force is required, the second member 41 having a flat annular facing surface facing the annular groove 33 of the first member 31 is used.

  Further, when the second member 41 having the annular protrusion 43 or the annular recess 44 is used, a member having a different projection dimension of the annular protrusion 43 or a depth dimension of the annular recess 44 is selectively selected according to a required sealing force. By using it, the sealing force can be adjusted more finely.

  Further, as the second member 41, as shown in FIG. 6, one or a plurality (two in FIG. 6) of ring-shaped grooves 42a may be formed in the sliding hole. If it does in this way, while ensuring the coaxiality of piston 51 and cylinder 12, the contact area with piston 51 can be reduced, the sliding resistance of piston 51 can be reduced, and the smooth sliding of piston 51 is aimed at. be able to.

  Further, in the above-described pump 11, when the annular groove 33 is formed in the first member 31, the axial thickness in the vicinity of the sliding hole 32 of the first member 31 is reduced, and the strength is reduced. Therefore, as shown in FIG. 7, the first member 31 may be formed so that the cylindrical seal plate portion 34 extends outward in the axial direction (z-axis direction in FIG. 7). Thus, if the cylindrical seal plate portion 34 is extended in the axial direction to ensure the length necessary for sealing with the piston 51, the annular groove 33 can be made shallow, and the axial direction of the first member 31 can be reduced. A sufficient thickness can be secured to suppress a decrease in strength.

  The cross-sectional shape and dimensions of the annular groove 33 of the first member 31 of the pump 11 and the elastic ring 55 disposed in the annular groove 33 are not limited to those of the present embodiment. By appropriately deforming the cross-sectional shapes and dimensions of the annular groove 33 and the elastic ring 55 according to the required sealing force, the pump 11 in which the cylinder 12 and the piston 51 are sealed with an appropriate sealing force can be obtained. it can.

Further, the number of the elastic rings 55 is not limited to one, and a plurality of elastic rings 55 may be arranged in the annular groove 33 in the axial direction or the radial direction.
Furthermore, although the said embodiment demonstrated the case where the liquid was transferred as the pump 11, this invention is applicable also to the pump which transfers not only a liquid but gas.

Claims (3)

A cylinder liquid inlet passage and liquid discharge passage have a pump chamber which communicates with intake port and the discharge port is formed,
A frame member joined to the rear end side of the cylinder;
A joining screw for fastening the cylinder and the frame member in a state in which the joining surfaces are in contact with each other;
A piston that is spaced from the inner surface of the cylinder and the inner surface of the frame member, connected to a moving mechanism provided on the rear end side of the frame member, and supported so as to be reciprocally movable;
A seal part that seals the gap between the cylinder and the frame member and the piston to define the pump chamber;
The exposed surface exposed to the pump chamber of the seal portion, is non positive displacement guaranteed surface deformation in the inner pressure of the pump chamber, and,
The seal portion, the piston sliding hole is slidably inserted, the distance from the sliding hole in the plane outwardly of the previous SL exposed surface open to the surface of the opposite side in the opposite surface A first member having an annular groove formed between the sliding hole and the annular groove, and an opening of the annular groove with respect to the first member. A second member mounted on the side and having a sliding hole through which the piston is slidably inserted ,
By fastening the joining screw, the annular elastic member disposed in the annular groove is deformed so as to be crushed in the axial direction and spread in the radial direction, whereby the cylindrical seal plate portion is radially moved from the elastic member. The inner peripheral surface of the sliding hole of the first member is pressed against the outer peripheral surface of the piston by receiving an inward pressing force, and the repulsive force of the elastic member crushed in the axial direction is The pump , wherein the first member and the second member act in a direction away from each other and the first member is pressed against the cylinder. 2. The pump according to claim 1 , wherein the first member is mounted with the second member in which an annular facing surface facing the annular groove is a convex surface, a flat surface, or a concave surface. .   The pump according to claim 1 or 2, wherein a thickness dimension of the cylindrical seal plate portion is 0.1 to 1.0 mm.

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