US-12618404-B2 - Seal structure for reciprocating pump with cylindrical collar portion

US12618404B2US 12618404 B2US12618404 B2US 12618404B2US-12618404-B2

Abstract

A seal structure configured to be located between a space forming member forming a columnar inner space and a columnar reciprocating member move in the inner space. The seal structure includes an annular seal member that is configured to be located in the inner space, an annular pressing portion which is located adjacent to the seal member and is configured to press the seal member in an axial direction, a compressive coil spring which is located adjacent to the pressing portion, and a cylindrical collar portion. The cylindrical collar portion is at least partially surrounded by the compressive coil spring to avoid interference between the compressive coil spring and the reciprocating member.

Inventors

Nobuo Tojo
Yoshitaka Yamanaka

Assignees

MARUYAMA MFG. CO., INC.

Dates

Publication Date: 20260505
Application Date: 20230927
Priority Date: 20221026

Claims (17)

1 . A seal structure configured to be located between a cylinder of a reciprocating pump forming a columnar inner space and a columnar reciprocating member of the reciprocating pump moving in a reciprocating manner in an axial direction in the inner space, the seal structure comprising: an annular seal member that is configured to be located in the inner space; an annular pressing portion which is located adjacent to the seal member and is configured to press the seal member in the axial direction; a compressive coil spring which is located adjacent to the pressing portion; a cylindrical collar formed integrally with the pressing portion, wherein the cylindrical collar is at least partially surrounded by the compressive coil spring to avoid interference between the compressive coil spring and the reciprocating member; and a regulation pipe configured to regulate a position of the compressive coil spring and having an outer cylindrical surface extending in the axial direction and partially located in the inner space, the regulation pipe including an annular stepped portion which protrudes from the outer cylindrical surface radially outward to contact the cylinder in the axial direction, wherein the annular stepped portion is located approximately at a center of the regulation pipe in the axial direction, wherein a first end of the regulation pipe extends from the annular stepped portion in the axial direction and contacts both the compressive coil spring and the cylindrical collar in the axial direction, and wherein a second end of the regulation pipe extends from the annular stepped portion in the axial direction opposite to the first end, the second end protruding outside of the cylinder in the axial direction.
2 . The seal structure according to claim 1 , further comprising a backup ring located between the reciprocating member and the cylinder, wherein a clearance is formed between the reciprocating member and the backup ring in the radial direction, and wherein the seal member is located between the pressing portion and the backup ring in the axial direction and separates the pressing portion from the backup ring.
3 . A reciprocating pump comprising: a cylinder portion including an inner peripheral surface; a plunger located in the cylinder portion and configured to move in a reciprocating manner in an axial direction in the cylinder portion; a stepped wall portion integrally formed with the cylinder portion and protruding from the inner peripheral surface toward the plunger in a radial direction of the cylinder portion, the stepped wall portion spaced away from an end of the cylinder portion in the axial direction; a seal structure comprising: an annular seal member located between and contacting both the plunger and the inner peripheral surface of the cylinder portion; a spring located between the plunger and the cylinder portion in the radial direction, and configured to press the seal member toward the stepped wall portion; a communicating pipe having an outer cylindrical surface extending in the axial direction and partially located in the cylinder portion, the communicating pipe including an annular stepped portion which protrudes outward from the outer cylindrical surface in the radial direction; and a backup ring including an inner ring surface facing the plunger and forming a clearance between the plunger and the inner peripheral surface of the cylinder portion in the radial direction, the backup ring located between and contacting both the seal member and the stepped wall portion in the axial direction; a cylindrical collar located between the plunger and the spring; and a pressing portion integrally formed with the cylindrical collar and located between the plunger and the inner peripheral surface of the cylinder portion in the radial direction, the pressing portion located between the spring and the seal member in the axial direction and contacting the seal member, wherein the cylinder portion includes a recessed portion which contacts the annular stepped portion of the communicating pipe in the axial direction to regulate a position of the spring, wherein the reciprocating pump includes a manifold having a flow passage that is fluidly coupled to the communicating pipe, wherein a first end of the communicating pipe extends in the axial direction from the annular stepped portion and contacts the spring in the axial direction, wherein a second end of the communicating pipe extends from the annular stepped portion in the axial direction opposite to the first end, the second end located in the flow passage of the manifold, wherein the spring is configured to press the seal member via the pressing portion, wherein the seal member is located between the pressing portion and the backup ring in the axial direction so that the pressing portion is separated from the backup ring, wherein the second end of the communicating pipe abuts the cylindrical collar in the axial direction, wherein the communicating pipe is configured to press the spring between the communicating pipe and the pressing portion, and wherein the annular stepped portion is located approximately at a center of the communicating pipe in the axial direction.
4 . The reciprocating pump according to claim 3 , wherein the pressing portion and the cylindrical collar are integrally formed with each other, and are made of resin, wherein an inner peripheral surface of the cylindrical collar is flush with an inner peripheral surface of the pressing portion, and wherein a clearance is formed between the plunger and the inner peripheral surfaces in the radial direction.
5 . The reciprocating pump according to claim 4 , wherein an outer diameter of the cylindrical collar is smaller than an outer diameter of the pressing portion.
6 . The reciprocating pump according to claim 3 , wherein the cylindrical collar is located between the plunger and the spring in the axial direction, wherein the seal member is located between the cylindrical collar and the backup ring in the axial direction, and wherein the communicating pipe is configured to abut the cylindrical collar and position the cylindrical collar.
7 . The reciprocating pump according to claim 3 , wherein the cylindrical collar is located between the plunger and the spring in the radial direction, wherein the inner peripheral surface of the cylinder portion is fluidly coupled to the flow passage of the manifold via the communicating pipe, the inner peripheral surface forming a part of a pump chamber in which the plunger is located, and wherein the cylindrical collar is located between the communicating pipe and the stepped wall portion in the axial direction.
8 . The reciprocating pump according to claim 3 , wherein the seal member comprises an annular first packing abutting the backup ring and an annular second packing adjacent to the first packing in the axial direction and abutting the pressing portion.
9 . The reciprocating pump according to claim 3 , further comprising: a first seal ring located between the communicating pipe and the cylinder portion in the axial direction; and a second seal ring located between the communicating pipe and the manifold in the axial direction, wherein the annular stepped portion of the communicating pipe is located between the first seal ring and the second seal ring in the axial direction.
10 . The reciprocating pump according to claim 3 , wherein the manifold contacts the second end of the communicating pipe and sandwiches the annular stepped portion between the manifold and the recessed portion in the axial direction.
11 . The reciprocating pump according to claim 3 , wherein the flow passage includes a pump chamber receiving the second end of the communicating pipe, and wherein the reciprocating pump includes a seal ring located between the outer cylindrical surface of the second end and the manifold in the pump chamber.
12 . The reciprocating pump according to claim 3 , wherein the cylindrical collar is located between the plunger and the spring in the radial direction, wherein the pressing portion protrudes outward from the cylindrical collar in the radial direction, and wherein the pressing portion includes an end surface that contacts the seal member in the axial direction.
13 . A reciprocating pump comprising: a cylinder portion including an inner peripheral surface; a plunger located in the cylinder portion and configured to move in a reciprocating manner in an axial direction in the cylinder portion; a stepped wall portion integrally formed with the cylinder portion and protruding from the inner peripheral surface toward the plunger in a radial direction of the cylinder portion, the stepped wall portion spaced away from an end of the cylinder portion in the axial direction; a seal structure comprising: an annular seal member located between and contacting both the plunger and the inner peripheral surface of the cylinder portion; a spring located between the plunger and the cylinder portion in the radial direction, and configured to press the seal member toward the stepped wall portion; a communicating pipe having an outer cylindrical surface extending in the axial direction and partially located in the cylinder portion, the communicating pipe including an annular stepped portion which protrudes outward from the outer cylindrical surface in the radial direction; and a backup ring including an inner ring surface facing the plunger and forming a clearance between the plunger and the inner peripheral surface of the cylinder portion in the radial direction, the backup ring located between and contacting both the seal member and the stepped wall portion in the axial direction; and a second seal member located between the plunger and the inner peripheral surface of the cylinder portion in the radial direction, the second seal member having a lower pressure resistance than the seal member, wherein the cylinder portion includes a recessed portion which contacts the annular stepped portion of the communicating pipe in the axial direction to regulate a position of the spring, wherein the reciprocating pump includes a manifold having a flow passage that is fluidly coupled to the communicating pipe, wherein a first end of the communicating pipe extends in the axial direction from the annular stepped portion and contacts the spring in the axial direction, wherein a second end of the communicating pipe extends from the annular stepped portion in the axial direction opposite to the first end, the second end located in the flow passage of the manifold, and wherein the stepped wall portion is located between the second seal member and the backup ring in the axial direction, the stepped wall portion including: a front surface contacting the backup ring; and a tapered surface located between the front surface and the second seal member in the axial direction.
14 . The reciprocating pump according to claim 13 , wherein the front surface of the stepped wall portion is perpendicular to the axial direction, and wherein an end surface of the backup ring is perpendicular to the axial direction and contacts the front surface of the stepped wall portion in the axial direction.
15 . The reciprocating pump according to claim 14 , wherein the stepped wall portion includes an inner circumferential surface that faces the plunger, and wherein the tapered surface of the stepped wall portion is tapered away from the plunger such that a diameter of the tapered surface uniformly increases in the axial direction from the inner circumferential surface of the stepped wall portion toward the second seal member.
16 . A reciprocating pump comprising: a cylinder portion including an inner peripheral surface; a plunger located in the cylinder portion and configured to move in a reciprocating manner in an axial direction in the cylinder portion; a first seal member located between the plunger and the inner peripheral surface and contacting the plunger and the inner peripheral surface in a radial direction of the cylinder portion; a spring located between the plunger and the inner peripheral surface in the radial direction, and configured to press the first seal member; a communicating pipe partially located in the cylinder portion and contacting the spring to regulate a position of the spring; a backup ring located between the plunger and the cylinder portion in the axial direction and contacting the first seal member, the backup ring including an inner ring surface spaced apart from and facing the plunger; a second seal member located between the plunger and the inner peripheral surface of the cylinder portion; and a stepped wall portion integrally formed with the cylinder portion and protruding from the inner peripheral surface toward the plunger, the stepped wall portion located between the backup ring and the second seal member in the axial direction, wherein the stepped wall portion includes: a front surface contacting the backup ring; a tapered surface located between the front surface and the second seal member in the axial direction; and an inner circumferential surface that connects the front surface to the tapered surface and faces the plunger, and wherein the tapered surface of the stepped wall portion is tapered away from the plunger such that a diameter of the tapered surface uniformly increases in the axial direction from the inner circumferential surface of the stepped wall portion toward the second seal member.
17 . A reciprocating pump comprising: a cylinder portion including an inner peripheral surface; a plunger located in the cylinder portion and configured to move in a reciprocating manner in an axial direction in the cylinder portion; a first seal member located between the plunger and the inner peripheral surface and contacting the plunger and the inner peripheral surface in a radial direction of the cylinder portion; a spring located between the plunger and the inner peripheral surface in the axial direction, and configured to press the first seal member; a communicating pipe partially located in the cylinder portion and contacting the spring to regulate a position of the spring; a backup ring located between the plunger and the cylinder portion in the axial direction and contacting the first seal member, the backup ring including an inner ring surface spaced apart from and facing the plunger; a second seal member located between the plunger and the inner peripheral surface of the cylinder portion; and a stepped wall portion integrally formed with the cylinder portion and protruding from the inner peripheral surface toward the plunger, the stepped wall portion located between the backup ring and the second seal member in the axial direction, wherein the communicating pipe includes: an outer cylindrical surface extending in the axial direction and partially located in the cylinder portion; and an annular stepped portion which protrudes outward from the outer cylindrical surface in the radial direction, the annular stepped portion located approximately at a center of the communicating pipe in the axial direction, wherein the cylinder portion includes a recessed portion extending outward from the inner peripheral surface in the radial direction, the recessed portion receiving the annular stepped portion and contacting the annular stepped portion in the axial direction to regulate a position of the spring, and wherein the stepped wall portion is located between the recessed portion and the second seal member in the axial direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2022-171539, filed on Oct. 26, 2022. The entire contents of which are incorporated herein by reference. BACKGROUND Field The present disclosure relates to a seal structure and a reciprocating pump. Description of the Related Art Japanese Unexamined Patent Application Publication No. S63-57879 discloses a plunger pump. In this plunger pump, a seal member and a compressive coil spring are arranged on an inner peripheral portion of a seal casing that defines a pump chamber. As the seal member is pressed in an axial direction by a biasing force of the compressive coil spring, the seal member is positioned. SUMMARY Disclosed herein is an example seal structure. An example seal structure is disposed between a space forming member that forms a columnar inner space and a columnar reciprocating member that moves in a reciprocating manner in an axial direction in the inner space. The seal structure includes an annular seal member that is disposed in the inner space, an annular pressing portion which is disposed adjacent to the seal member and presses the seal member in the axial direction, a compressive coil spring which is disposed adjacent to the pressing portion, and a cylindrical collar portion which is surrounded by the compressive coil spring to avoid interference between the compressive coil spring and the reciprocating member. Additionally, an example reciprocating pump is disclosed herein. An example reciprocating pump includes a cylinder portion, a plunger located in the cylinder portion and configured to move in a reciprocating manner in an axial direction in the cylinder portion. The reciprocating pump includes an annual seal member located between the plunger and the cylinder portion, a spring located between the plunger and the cylinder portion, and configured to press the seal member, and a cylindrical collar portion located between the plunger and the spring. In some examples, space forming a so-called pump chamber is formed in a region on the front side of the seal member in the axial direction in the columnar inner space formed by the inner space forming member. Since the cylindrical collar portion is disposed in the compressive coil spring, a space in which the compressive coil spring is disposed and a space which constitutes the pump chamber are isolated from each other. Accordingly, the occurrence of cavitation may be suppressed. In some examples, the pressing portion and the collar portion are integrally formed with each other. In some examples, the efficiency of the manufacturing process may be improved by decreasing the number of parts. Additionally, in an example, the pressing portion and the collar portion may be formed separately from each other. In some examples, in a state in which a regulation member for regulating the position of the compressive coil spring is disposed in the inner space and the regulation member regulates the compressive coil spring, the length of the compressive coil spring in the axial direction is the same as the length of the collar portion in the axial direction. In some examples, since not only the compressive coil spring but also the collar portion press the pressing portion in the axial direction, the wire diameter of the compressive coil spring can be decreased. In some examples, the seal member includes an annular concave portion having a V-shaped cross-section and serving as a contact surface with the pressing portion and the pressing portion includes an annular convex portion having a V-shaped cross-section corresponding to the concave portion and serving as a contact surface with the seal member. In this configuration, the misalignment of the axial centers of the seal member and the pressing portion are suppressed. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view illustrating an example reciprocating pump. FIG. 2 is an enlarged cross-sectional view illustrating a seal structure of the reciprocating pump of FIG. 1. FIG. 3 is a cross-sectional view illustrating an example seal structure. FIG. 4 is a cross-sectional view illustrating another example seal structure. DETAILED DESCRIPTION In the following description, with reference to the drawings, the same reference numbers are assigned to the same components or to similar components having the same function, and overlapping description is omitted. Hereinafter, a reciprocating pump having an example seal structure will be described with reference to the accompanying drawings. As an example reciprocating pump, a so-called horizontal triple plunger pump in which three plungers constituting reciprocating members are arranged in parallel in the horizontal direction will be described. Additionally, in the following description, “up” and “down” are defined with reference to the state in which the reciprocating pump is placed on a horizontal plane, “front” an