Reciprocating Pump

Abstract

To provide a reciprocation pump capable of compatibly securing a water absorption flow path area and securing an appropriate bolt diameter.SOLUTION: A piston metal fitting 16 having a piston packing 17 for slide-contacting with a cylinder 2 provided on its outer periphery side is fixed to a piston body 4 on its rear side with a fixing bolt 21 provided on its rear end face, while a water absorption flow path 28 is passed thought the interior of the piston metal fitting 16 at a front side further than the fixing bolt 21 for absorbing a use liquid. In this construction, the fixing bolt 21 for the piston metal filling 16 and the water absorption flow path 28 are not arranged in parallel to each other in a radial direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a reciprocating pump. [Background technology]

[0002] A known conventional reciprocating pump is that described in Patent Document 1. The reciprocating pump described in Patent Document 1 includes a piston having a cylindrical water intake valve seat fitted and fixed around the piston rod that reciprocates within a cylinder, the water intake valve seat having a plurality of water intake passages (through holes) along the circumferential direction that communicate between the front and rear in the axial direction, and a piston packing (packing) that is in sliding contact with the cylinder and is held on the outer periphery of the water intake valve seat, a water intake valve that is fitted around the piston rod so as to be movable in the axial direction, is located on the axial front side of the water intake valve seat, and opens and closes the water intake passage by lifting off and seating on the water intake valve seat, and a pressing means that presses the water intake valve so that it seats on the water intake valve seat.

[0003] With this reciprocating pump, when the piston moves back, the pump chamber formed on the axial front side of the cylinder is depressurized and the intake valve opens, allowing the used liquid to be sucked into the pump chamber through the intake flow path, while when the piston moves forward, the pump chamber is pressurized and the intake valve closes, allowing the used liquid to be discharged from the pump chamber. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-188537 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned reciprocating pump, a bolt hole is required in the water intake valve seat for assembling and fixing to the center of the piston packing, and the water intake flow path is formed in the area between the outside of the bolt hole and the inside of the piston packing, which poses the problem of difficulty in achieving both an appropriate water intake flow path and selecting appropriate bolts for assembling and fixing.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to provide a reciprocating pump that can ensure both a sufficient water intake flow path area and an appropriate bolt diameter. [Means for solving the problem]

[0007] The reciprocating pump (1) according to the present invention includes a piston (3) that reciprocates within a cylinder (2) and has a piston packing (17) attached to its outer periphery in sliding contact with the cylinder (2). When the piston (3) moves backward, the pressure in a pump chamber (50) formed on the axial front side of the cylinder (2) is reduced, and the intake valve (33) is opened, allowing the liquid to be sucked into the pump chamber (50) through the intake flow path (28). When the piston (3) moves forward, the pressure in the pump chamber (50) is increased, and the intake valve (33) is opened. ) is closed and the liquid used is discharged from the pump chamber (50), and the piston (3) is provided with a piston fitting (16) at its tip, and the piston fitting (16) is provided with a piston packing (17) on its outer periphery and with a fixing bolt (21) at its rear end face which is fixed to the piston body (4) behind the piston fitting (16), and a water intake flow path (28) is passed through the inside of the piston fitting (16) on the front side of the fixing bolt (21).

[0008] In this reciprocating pump (1), the piston fitting (16), which has a piston packing (17) on its outer periphery that is in sliding contact with the cylinder (2), is fixed to the piston body (4) at its rear side by a fixing bolt (21) provided on its rear end face, while a water intake passage (28) for absorbing the liquid used is passed through the interior of the piston fitting (16) forward of the fixing bolt (21). In this way, the fixing bolt (21) of the piston fitting (16) and the water intake passage (28) are not aligned in the radial direction, so that it is possible to ensure both a sufficient water intake passage area and an appropriate bolt diameter.

[0009] Here, a specific example of a configuration that provides the above-described functions and effects is a configuration in which the fixing bolt (21) and the water intake passage (28) are coaxially arranged in series.

[0010] In addition, if the piston fitting (16) is provided with a plurality of inlet flow paths (30) each having one end opening to the outer peripheral surface of the piston fitting (16) and the other end communicating with the water intake flow path (28) for absorbing the liquid used into the water intake flow path (28), water can be efficiently absorbed without the need for alignment.

[0011] Furthermore, it is preferable that the water intake flow path (28) opens into the tip end surface of the piston fitting (16), which serves as a water intake valve seat (26) on which the water intake valve (33) seats and unseats, that a valve sack (22) having an opening (35) communicating the inside and outside at its tip end is provided in front of the piston fitting (16) so as to cover the water intake valve seat (26), and that the water intake valve (33) and a spring (32) for biasing the water intake valve (33) so as to seat on the water intake valve seat (26) are provided inside the valve sack (22).

[0012] In this configuration, when the piston (3) moves from top dead center to bottom dead center and the pump switches from the discharge stroke to the intake stroke, inertial force and piston acceleration act on the intake valve (33) and spring (32) to open the intake valve (33), and the differential pressure across the valve acts on the intake valve (33), allowing the intake valve (33) to be efficiently opened. Also, when the piston (3) moves from bottom dead center to top dead center and the pump switches from the intake stroke to the discharge stroke, inertial force and piston acceleration act on the intake valve (33) and spring (32) to close the intake valve (33), and the differential pressure across the valve acts on the intake valve (33), allowing the intake valve (33) to be efficiently closed. [Effects of the Invention]

[0013] In this way, according to the present invention, it is possible to ensure both the water intake flow path area and an appropriate bolt diameter. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing a reciprocating pump device including a reciprocating pump according to an embodiment of the present invention. [Figure 2] 2 is an enlarged cross-sectional view showing the reciprocating pump on the left side in FIG. 1 with the piston positioned at the bottom dead center. FIG. [Figure 3] 2 is an enlarged cross-sectional view showing the reciprocating pump on the right side in FIG. 1, with the piston positioned at the top dead center. FIG. [Figure 4] FIG. 4 is a perspective view showing the piston with a water intake valve in FIGS. 1 to 3. [Figure 5] FIG. 5 is a side view of the piston with the water intake valve shown in FIG. 4. [Figure 6] FIG. 5 is an exploded perspective view of the piston with the intake valve shown in FIG. 4. [Figure 7] FIG. 5 is a vertical cross-sectional view of the piston with the water intake valve shown in FIG. 4. [Figure 8] FIG. 8 is a side view showing the piston fitting in FIGS. 4 to 7. [Figure 9] FIG. 9 is a vertical cross-sectional view of the piston fitting shown in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments of a reciprocating pump according to the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a cross-sectional view showing a reciprocating pump device including a reciprocating pump according to an embodiment of the present invention, Figs. 2 and 3 are enlarged cross-sectional views showing the reciprocating pumps on the left and right sides in Fig. 1, respectively, Figs. 4 to 7 are views showing a piston with an intake valve, and Figs. 8 and 9 are views showing a piston fitting.

[0016] The reciprocating pump of this embodiment is used in devices such as power sprayers, and various liquids are used as the liquid used in the reciprocating pump depending on the application, but in this embodiment, a chemical liquid is used.

[0017] 1, a pair of reciprocating pumps 1 are arranged coaxially and facing opposite directions. The reciprocating pump 1 generally includes a cylinder 2, a piston 3 that reciprocates within the cylinder 2, and a pump chamber 50 formed on the axial front side of the cylinder 2.

[0018] The piston 3 includes a piston body 4 and a piston 5 with a water intake valve attached and fixed to the front side of the piston body 4 (see Figures 4 to 7). A drive unit 6 for driving the piston 3 is located between the two reciprocating pumps 1 and is made up of a crankshaft 7 and a connection rod 9 attached to an eccentric cam 8 of the crankshaft 7 and connected to the piston body 4. A bearing 10 for reducing wear is arranged between the eccentric cam 8 of the crankshaft 7 and the connection rod 9. When the crankshaft 7 rotates, the rotational motion is converted into reciprocating motion via the bearing 10 and the connection rod 9, causing the piston 3 (piston body 4 and piston 5 with a water intake valve) to reciprocate.

[0019] The crankshaft 7, eccentric cam 8, connecting rod 9, and bearing 10 are housed in a case 11. A packing 12 is provided in the case 11, which comes into sliding contact with the piston body 4 of the reciprocating piston 3 to seal between the pump chamber 50 side and the crankshaft 7 side. As shown in FIGS. 1 to 3, the packing 12 is held in position and fixed by an adjacent packing gland 13. Inside the packing gland 13 and the cylinder 2, water intake passages 14 and 15 through which the working liquid flows are provided, respectively.

[0020] As shown in FIGS. 1 to 7, the piston 5 with water intake valve that constitutes the tip of the piston 3 includes a piston metal fitting 16, a piston packing 17, and a valve sack assembly 19 (see FIG. 6 in particular).

[0021] As shown in Figures 1 to 3 and 6 to 9 (particularly Figures 8 and 9), the piston fitting 16 has a shape in which a fixing bolt 21 for attaching it to the piston body 4 is connected to the center of the rear end surface of the approximately cylindrical tip portion 20.

[0022] 2, 3, 7 to 9, the front end portion 20 is provided with a male thread 23 for attaching the valve sack 22 of the valve sack assembly 19, and a flange portion 24 is provided in the middle of the axial direction of the rear end portion. Between the male thread 23 and flange portion 24 of the front end portion 20, an annular recess 25 is provided for attaching the piston packing 17.

[0023] The tip surface of the tip portion 20 is recessed in the shape of a truncated cone (a mortar shape), and an opening 27 is provided in the bottom surface at the center of this recessed surface 26. A cylindrical hole serving as a water intake passage 28 is provided to extend from the opening 27 toward the rear end of the tip portion 20. Four equally spaced openings 29 that communicate the inside and outside in the radial direction are provided on the outer peripheral surface of the tip portion 20 rearward of the flange 24, and inlet passages 30 that allow the working liquid to be sucked into the water intake passage 28 are provided from the openings 29 toward the central water intake passage 28. The inlet passages 30 form a cross when viewed in the axial direction. The number of inlet passages 30 is not limited to four, and it is preferable to have more than one.

[0024] The piston packing 17 is made of an elastic body and is adapted to slide against the cylinder 2. The piston packing 17 is attached to the recess 25 of the piston fitting 16 by elastic fastening or thermal welding so as to abut against the flange 24 of the piston fitting 16.

[0025] As shown in FIGS. 2 to 7, the valve sack assembly 19 includes a valve sack 22 in the shape of a cylinder with a top, a spring 32, and a water intake valve 33.

[0026] The outer peripheral surface of the valve sack 22 has a shape that roughly follows the inner peripheral surface of the pump chamber 50, and the inner peripheral surface of the rear half thereof is provided with a female thread 34 for attachment to the piston fitting 16. Four openings 35 (see Figures 4 to 6) that communicate between the inside and outside are provided in the front half of the valve sack 22 along the circumferential direction. These openings 35 are for the passage of the liquid used, and are open from the side to the top of the valve sack 22.

[0027] The valve sack 22 accommodates a spring 32 and a water intake valve 33 from the front end (top surface) to the rear end.

[0028] The valve sack 22 is fixed to the tip end 20 of the piston fitting 16 by threading its female screw 34 onto the male screw 23 of the piston fitting 16 .

[0029] In this state, the water intake valve 33 is biased by a spring 32 interposed between the top surface of the valve sack 22 and the water intake valve 33, and is seated on the recessed surface 26 of the piston fitting 16 which functions as a water intake valve seat, closing the opening 27 of the water intake flow path 28.

[0030] The piston 5 with water intake valve having such a configuration is fixed to the piston body 4 by screwing the fixing bolt 21 of the piston fitting 16 into the female thread 38 (see Figures 2 and 3) formed at the tip of the piston body 4.

[0031] As shown in Figures 1 to 3, a discharge flow path 36 is connected to the side of the pump chamber 50 in which the intake valve-equipped piston 5 reciprocates, and a discharge valve 37 is provided at the end of the discharge flow path 36 so as to be able to open and close.

[0032] In the reciprocating pump device 100 configured as described above, when the drive unit 6 is driven, the pistons 3 reciprocate while the piston packings 17 of the pistons 3 are in sliding contact with the cylinders 2, and one of the pistons 3 moves backward (see the piston on the left in FIG. 1). As the pistons 3 move from top dead center to bottom dead center, as shown in FIG. 2, the pressure in the pump chamber 50 is reduced, and due to actions including the differential pressure across the valve (described in detail later), the water intake valve 33 lifts off the water intake valve seat 26, which is a recessed surface, against the biasing force of the spring 32, and the water intake valve 33 opens.

[0033] The liquid used flows through a water intake flow path (not shown) provided within the case 11, then through water intake flow paths 14 and 15 inside the gasket 13 and the cylinder 2, multiple openings 29 in the piston fitting 16, and multiple inlet flow paths 30 within the piston fitting 16b, and then through a water intake flow path 28 extending in the axial direction, and is sucked into the pump chamber 50 from an opening 27 in the water intake valve seat 26 of the piston fitting 16 through an opening 35 in the valve sack 22 (see Figures 4 to 6).

[0034] Meanwhile, the other piston 3 moves forward in the opposite direction to the first piston 3 (see the piston on the right in Figure 1), and as it moves from bottom dead center to top dead center as shown in Figure 3, the pump chamber 50 is pressurized, and due to actions including the differential pressure across the valve (described in detail later), the water intake valve 33 seats on the water intake valve seat 26 and closes.

[0035] The working liquid that has been sucked into the pump chamber 50 is compressed by the valve sack 22, passes through the discharge flow path 36, and is discharged from the opened discharge valve 37 (see FIG. 1).

[0036] Thus, according to this embodiment, the piston fitting 16, which is provided with the piston packing 17 on its outer periphery that slides against the cylinder 2, is fixed to the piston body 4 at its rear side by the fixing bolt 21 provided on its rear end face, while the water intake flow path 28 for absorbing the liquid used is passed through the interior of the piston fitting 16 forward of the fixing bolt 21, and since the fixing bolt 21 of the piston fitting 16 and the water intake flow path 28 are not aligned radially, it is possible to ensure both a sufficient water intake flow path area and an appropriate bolt diameter.

[0037] In particular, in this embodiment, the fixing bolt 21 and the water intake passage 28 are arranged in series on the same axis, so that the functions and effects thereof can be effectively exhibited.

[0038] In addition, the piston fitting 16 has one end that opens onto the outer peripheral surface of the piston fitting 16 and the other end that is connected to the water intake flow path 28, and is provided with a plurality of inlet flow paths 30 for absorbing the used liquid into the water intake flow path 28, so that water can be efficiently absorbed without the need for alignment.

[0039] Furthermore, water intake flow path 28 opens into the tip surface of piston fitting 16, which serves as water intake valve seat 26 on which water intake valve 33 seats and unseats. A valve sack 22 having an opening 35 at its tip side that communicates between the inside and outside is provided in front of piston fitting 16 so as to cover water intake valve seat 26. Inside valve sack 22 are provided water intake valve 33 and a spring 32 that urges water intake valve 33 to seat on water intake valve seat 26. Therefore, as shown in FIG. 2, when piston 3 moves from top dead center to bottom dead center and the pump switches from the discharge stroke to the water intake stroke, inertial force and piston acceleration act on water intake valve 33 and spring 32 to open water intake valve 33, and the differential pressure across the valve acts on water intake valve 33, enabling water intake valve 33 to be opened efficiently. Furthermore, as shown in FIG. 3, when the piston 3 moves from bottom dead center to top dead center and the pump switches from the intake stroke to the discharge stroke, inertial force and piston acceleration act on the intake valve 33 and spring 32 to close the intake valve 33, and the differential pressure across the valve also acts, allowing the intake valve 33 to be closed efficiently.

[0040] Furthermore, since the piston packing 17 and the water intake valve 33 are separate bodies, there are advantages in that the weight is light, the impact load with the water intake valve seat 26 is small, and noise can be reduced.

[0041] Although the present invention has been specifically described above based on the embodiments thereof, the present invention is not limited to the above embodiments and various modifications are possible.

[0042] In the following, the constituent elements of the present invention will be described with reference to the reference numerals in the drawings in order to compare the constituent elements of the present invention with the configurations of the embodiments. [Invention 1] A reciprocating pump (1) includes a piston (3) that reciprocates within a cylinder (2) and has a piston packing (17) on its outer periphery that is in sliding contact with the cylinder (2), and when the piston (3) moves backward, a pump chamber (50) formed on the axial front side of the cylinder (2) is depressurized and an intake valve (33) is opened, allowing the liquid used to be sucked into the pump chamber (50) through an intake flow path (28), while when the piston (3) moves forward, the pump chamber (50) is pressurized and the intake valve (33) is closed, allowing the liquid used to be discharged from the pump chamber (50), The piston (3) is provided with a piston fitting (16) at its tip, The piston fitting (16) is provided with the piston packing (17) on its outer circumferential side, and is provided with a fixing bolt (21) on its rear end surface, which is fixed to the piston body (4) rearward of the piston fitting (16); The reciprocating pump (1) is characterized in that the water intake passage (28) passes through the interior of the piston fitting (16) on the front side of the fixing bolt (21). [Invention 2] The reciprocating pump (1) according to the first aspect of the present invention is characterized in that the fixing bolt (21) and the water intake passage (28) are arranged in series on the same axis. [Invention 3] The reciprocating pump (1) according to Invention 2 is characterized in that the piston fitting (16) has one end that opens to the outer peripheral surface of the piston fitting (16) and the other end that communicates with the water intake flow path (28), and is provided with a plurality of inlet flow paths (30) for sucking the working liquid into the water intake flow path (28). [Invention 4] The water intake passage (28) opens to the tip end surface of the piston fitting (16), The tip end surface of the piston metal member (16) is a water intake valve seat (26) on which the water intake valve (33) is seated and unseated, A valve sack (22) having an opening (35) communicating the inside and outside at its tip end is provided on the front side of the piston fitting (16) so as to cover the water intake valve seat (26), The reciprocating pump (1) according to any one of inventions 1 to 3, wherein the valve sack (22) contains the water intake valve (33) and a spring (32) that biases the water intake valve (33) so that the water intake valve (33) seats on the water intake valve seat (26). [Explanation of symbols]

[0043] 1...reciprocating pump, 2...cylinder, 3...piston, 4...piston body, 16...piston fitting, 17...piston packing, 21...fixing bolt, 22...valve sack, 26...intake valve seat, 28...intake flow path, 30...inlet flow path, 32...spring, 33...intake valve, 35...opening, 50...pump chamber

Claims

1. A reciprocating pump (1) comprising a piston (3) that reciprocates within a cylinder (2) and has a piston packing (17) on its outer periphery that is in sliding contact with the cylinder (2), wherein when the piston (3) retracts, a pump chamber (50) formed on the axial front side of the cylinder (2) is depressurized and an intake valve (33) is opened, allowing the liquid used to be sucked into the pump chamber (50) through an intake flow path (28), while when the piston (3) advances, the pump chamber (50) is pressurized and the intake valve (33) is closed, allowing the liquid used to be discharged from the pump chamber (50), The piston (3) is provided with a piston fitting (16) at its tip, The piston metal fitting (16) is provided with the piston packing (17) on its outer circumferential side, and is provided with a fixing bolt (21) on its rear end surface, which is fixed to the piston body (4) rearward of the piston metal fitting (16), The reciprocating pump (1) is characterized in that the water intake passage (28) passes through only the interior of the piston fitting (16) on the front side of the fixing bolt (21).

2. 2. The reciprocating pump (1) according to claim 1, wherein the fixing bolt (21) and the water intake passage (28) are arranged in series on the same axis.

3. 3. The reciprocating pump (1) according to claim 2, wherein the piston fitting (16) is provided with a plurality of inlet passages (30), one end of which is open to the outer peripheral surface of the piston fitting (16) and the other end of which is connected to the water intake passage (28), for sucking the working liquid into the water intake passage (28).

4. The water intake passage (28) is opened to the tip end surface of the piston fitting (16), The tip end surface of the piston metal member (16) is a water intake valve seat (26) on which the water intake valve (33) is seated and unseated, A valve sack (22) having an opening (35) communicating the inside and outside at its tip end is provided on the front side of the piston fitting (16) so as to cover the water intake valve seat (26), 3. The reciprocating pump (1) according to claim 1 or 2, characterized in that the valve sack (22) contains the water intake valve (33) and a spring (32) that biases the water intake valve (33) so that it seats on the water intake valve seat (26).

5. A reciprocating pump (1) comprising a piston (3) that reciprocates within a cylinder (2) and has a piston packing (17) on its outer periphery that is in sliding contact with the cylinder (2), wherein when the piston (3) retracts, a pump chamber (50) formed on the axial front side of the cylinder (2) is depressurized and an intake valve (33) is opened, allowing the liquid used to be sucked into the pump chamber (50) through an intake flow path (28), while when the piston (3) advances, the pump chamber (50) is pressurized and the intake valve (33) is closed, allowing the liquid used to be discharged from the pump chamber (50), The piston (3) is provided with a piston fitting (16) at its tip, The piston metal fitting (16) is provided with the piston packing (17) on its outer circumferential side, and is provided with a fixing bolt (21) on its rear end surface, which is fixed to the piston body (4) rearward of the piston metal fitting (16), The water intake passage (28) is passed through the interior of the piston fitting (16) on the front side of the fixing bolt (21), The fixing bolt (21) and the water intake passage (28) are arranged in series on the same axis, The piston fitting (16) has one end that opens to the outer peripheral surface of the piston fitting (16) and the other end that communicates with the water intake flow path (28), and is provided with a plurality of inlet flow paths (30) for sucking the working liquid into the water intake flow path (28).

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