JP2004162646A - Reciprocating pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reciprocating pump for sufficiently discharging leakage liquid to the outside, even if a leakage amount of the liquid from seal packing becomes large. <P>SOLUTION: In the reciprocating pump 10, an annular partition board 46 is disposed in a seal packing pressor 44 to coaxially surround a piston 14 with a predetermined space therebetween. The seal packing pressor 44 has a cutout 48 and a flow passage 50 formed between the seal packing 40 and the partition board 46 to make the inside of the seal packing pressor 44 communicate with the outside thereof. By the constitution, the liquid leaking from the seal packing 40 is wiped away by the partition board 46 to be discharged from the cutout 48 to the outside through the flow passage 50. Therefore, even if the leakage amount of liquid from the seal packing becomes large, the leakage liquid is sufficiently discharged to the outside. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reciprocating pump for transporting a liquid by reciprocating a piston or a plunger (hereinafter, collectively referred to as a “piston”).
[0002]
[Prior art]
As a conventional reciprocating pump for transporting a liquid by reciprocating a piston, for example, a pump shown in FIG. 4 is known. The reciprocating pump 1 shown in FIG. 4 includes a cylinder 2, a piston 3 reciprocating in the cylinder 2, and a driving unit 4 for driving the piston 3. A so-called pump chamber 5 is formed at the end of the cylinder 2 opposite to the drive unit 4.
[0003]
In such a configuration, when the drive unit 4 moves the piston 3 in the direction of the arrow in FIG. 4, the pressure in the pump chamber 5 is reduced, and the liquid is sucked into the pump chamber 5. On the other hand, when the piston 3 is moved in the direction opposite to the arrow, the inside of the pump chamber 5 is pressurized, and the liquid is discharged from the pump chamber 5 to the outside.
[0004]
By the way, in order to prevent a part of the liquid in the pump chamber 5 from leaking to the driving section 4 side between the piston 3 and the cylinder 2, the seal packing 6 a and the seal packing 6 b Attached to. The seal packing 6a and the seal packing 6b are arranged at an end of the cylinder 2 on the driving section 4 side. The seal packing 6b is provided at a position closer to the drive section 4 than the seal packing 6a, and is pressed and fixed by a cylindrical seal packing retainer 7. Since the inner peripheral surface of the seal packing 6b is slidably in contact with the outer peripheral surface of the piston 3 in a liquid-tight manner, leakage of the liquid can be prevented.
[0005]
However, if the reciprocating pump 1 is used for a long time, the seal packing 6a and the seal packing 6b may be worn, and the liquid may pass through the seal packing 6b and reach the drive unit 4 side. For this reason, in the related art, a disk called a shake-off 8 is arranged at the end of the piston 2. Since the outside diameter of the shake-off 8 is larger than the outside diameter of the piston 3, the liquid leaking from the seal packing 6 b can be blocked and reciprocated together with the piston 3 to shake off outward. The shaken liquid is discharged to the outside through an opening 9 formed in the seal packing retainer 7 (for example, see Patent Document 1).
[0006]
[Patent Document 1]
JP-A-9-32930 (page 2-3, FIG. 1)
[0007]
[Problems to be solved by the invention]
However, in the reciprocating pump 1 described above, when the wear of the seal packing 6 b progresses or exceeds its life and the amount of leakage of the liquid increases, the liquid cannot be sufficiently discharged to the outside by the shake-off 8. There is. If the leaked liquid cannot be discharged to the outside, it may enter, for example, a crankcase (not shown) of the drive unit and cause various problems.
[0008]
Accordingly, the present invention has been made in view of such circumstances, and provides a reciprocating pump capable of sufficiently discharging the leaked liquid to the outside even if the amount of leaking liquid from the seal packing increases. The purpose is to:
[0009]
[Means for Solving the Problems]
To achieve the above object, a reciprocating pump (10) according to the present invention drives a cylinder (12), a piston (14) reciprocally arranged in the cylinder (12), and a piston (14). (16) and a seal disposed on the inner peripheral surface at the end of the cylinder (12) on the drive unit (16) side and in liquid-tight and slidable contact with the outer peripheral surface of the piston (14). A packing (40), a cylindrical seal packing retainer (44) for pressing and fixing the seal packing (40), and provided inside the seal packing retainer (44), coaxially surrounding the piston (14) with a predetermined gap. An annular partition plate (46) is provided, and the seal packing retainer (44) has a communication between the seal packing (40) and the partition plate (46) for communicating the inside and the outside of the seal packing retainer (44). Means (4 Is characterized in that 50) is formed.
[0010]
According to this configuration, the liquid leaking from the seal packing (40) is scraped off by the partition plate (46), and can be discharged to the outside of the seal packing presser (44) through the communication means (48, 50). When the space outside the seal packing retainer (44) communicates with the outside of the reciprocating pump (10), the liquid is discharged to the outside of the reciprocating pump (10).
[0011]
Further, it is preferable that the partition plate (46) is formed integrally with the seal packing retainer (44). By adopting such a configuration, the burden of disassembling and assembling during maintenance and the like can be reduced.
[0012]
Further, the gap between the piston (14) and the partition plate (46) is preferably 1.0 mm or less. If the gap is larger than 1.0 mm, the effect of scraping the liquid leaking from the seal packing (40) is reduced.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference characters.
[0014]
FIG. 1 is a longitudinal sectional view showing a reciprocating pump 10 for transporting a liquid by reciprocating a piston according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of FIG. The illustrated reciprocating pump 10 includes a cylinder 12, a piston 14 that reciprocates in the cylinder 12, and a driving unit 16 that drives the piston 14.
[0015]
The cylinder 12 is configured as a part of a pump casing 18. The pump casing 18 defines a pump chamber 20, and the pump chamber 20 is disposed adjacent to an end of the cylinder 12 opposite to the drive unit 16. A suction port 22 is formed on one side of the pump chamber 20, and a discharge port 24 is formed on the other side. A suction valve 26 is provided between the suction port 22 and the pump chamber 20, and allows only one-way flow from the suction port 22 to the pump chamber 20. A discharge valve 28 is provided between the pump chamber 20 and the discharge port 24. The discharge valve 28 allows only the flow from the pump chamber 20 to the discharge port 24.
[0016]
The drive unit 16 includes a crankcase 30 that forms a part of the pump casing 18, and a drive source (not shown) such as an electric motor disposed outside the crankcase 30.
[0017]
In the crankcase 30, a crankshaft 32 that rotates by receiving a driving force of a driving source, a piston element 36 connected to the piston 14 via a piston rod 34, and connects the piston element 36 and the crankshaft 32. A connection rod 38 is provided. When a drive source (not shown) is driven to rotate the crankshaft 32 in the crankcase 30 in a predetermined direction, the rotational force is transmitted through the connection rod 38, the piston source 36, and the piston rod 34, and the piston 14 is moved. It is configured to reciprocate in the cylinder 12.
[0018]
Further, the seal packing 39 and the seal packing 40 for shutting off liquid leaking between the cylinder 12 and the piston 14 are attached to the cylinder 12. The seal packing 39 and the seal packing 40 are annular bodies made of, for example, synthetic rubber, and the seal packing 39 is inserted into a large-diameter portion 41 formed at a central portion in the cylinder 12 from a side opposite to the drive unit 16. The seal packing 40 is inserted and fitted from the drive unit 16 side into the enlarged diameter portion 42 formed at the end of the cylinder 12 on the drive unit 16 side. In this position, the outer peripheral surface of the piston 14 is slidably and liquid-tightly in contact with the inner peripheral surfaces of the seal packing 39 and the seal packing 40 from the top dead center to the bottom dead center.
[0019]
In order to prevent the seal packing 40 from dropping off from the enlarged diameter portion 42 of the cylinder 12, a seal packing presser 44 is provided. The seal packing retainer 44 is disposed coaxially with the piston 14 and the piston rod 34 in the pump casing 18 so as to surround the piston 14 and the piston rod 34. In a state where the reciprocating pump 10 is assembled, one end face of the seal packing 40 is formed. The seal packing 40 is pressed against the step surface of the enlarged-diameter portion 42 and is fixed in contact with the end surface.
[0020]
As shown in FIG. 3, an annular partition plate 46 is coaxially arranged inside the seal packing retainer 44. The partition plate 46 is preferably formed integrally with the seal packing retainer 44 so that the partition plate 46 can be handled together with the seal packing retainer 44 during assembly and maintenance of the reciprocating pump 10.
[0021]
The center hole of the partition plate 46 has an inner diameter B larger than the outer diameter A of the piston 14, and the piston 14 can reciprocate with a predetermined gap inside. This gap (BA) is 1.0 mm or less, more preferably 0.5 mm or less, for the reasons described below. Further, the partition plate 46 is disposed closer to the drive section 16 than the end face of the seal packing retainer 44 on the seal packing 40 side. When the piston 14 is at the top dead center position (the position shown in FIGS. 1 and 2) in a state where the partition plate 46 is assembled to the reciprocating pump 10, the position of the end of the piston 14 on the drive unit 16 side is set. This is the position of the outer periphery. Therefore, even when the piston 14 moves to the bottom dead center, the partition plate 46 is always at a position surrounding the piston 14.
[0022]
Further, at an end of the partition plate 46 on the side in contact with the seal packing 40, at least one, preferably a plurality of notches 48 are formed in a portion between the end surface and the partition plate 46. The pump casing 18 is formed with a flow path 50 that communicates the notch 48 with the outside of the pump. The notch 48 and the flow path 50 constitute communication means for communicating the inside and the outside of the seal packing retainer 44.
[0023]
A shake-off 52 is coaxially attached to the end of the piston 14 on the drive unit 16 side. The shaking-off 52 is an annular disk, and is sandwiched between the piston 14 and the enlarged diameter portion of the piston rod 34. The shake-off 52 is located inside the piston 14 and the seal packing retainer 44, and serves to cut off the leaked liquid transmitted along the outer peripheral surface of the piston 14 and shake off outward as in the related art. Therefore, it is desirable that the outer diameter C of the shake-out 52 be sufficiently larger than the outer diameter A of the piston 14.
[0024]
At least one, preferably a plurality of openings 54 are formed in the seal packing retainer 44 in order to discharge the liquid shaken off by the shake-off 52 to the outside of the reciprocating pump 10. The opening 54 communicates with a flow path 50 formed in the pump casing 18.
[0025]
Next, the operation of the reciprocating pump having the above configuration will be described.
[0026]
First, when a drive source (not shown) is activated and the crankshaft 32 is rotated, the rotational force is transmitted via the connection rod 38, the piston element 36 and the piston rod 34, and the piston 14 reciprocates in the cylinder 12. . When the piston 14 moves in the direction indicated by the arrow in FIG. 1, the pressure in the pump chamber 20 is reduced, the suction valve 26 and the discharge valve 28 are opened and closed, respectively, and the liquid at the suction port 22 passes through the suction valve 26. It is sucked into the pump chamber 20. On the other hand, when the piston 14 moves in the direction opposite to the arrow, the inside of the pump chamber 20 is pressurized, the suction valve 26 and the discharge valve 28 are closed and opened, respectively, and the liquid in the pump chamber 20 is discharged through the discharge valve 28. It is discharged to the outlet 24. The liquid is transported in one direction from the suction port 22 to the discharge port 24 by repeating the suction step and the discharge step.
[0027]
During this transportation, part of the liquid in the pump chamber 20 flows between the piston 14 and the cylinder 12 toward the drive unit 16. This liquid is sealed by the seal packing 39. If the inner peripheral surface of the seal packing 39 is worn, a part of the liquid passes through the seal packing 39 and the liquid between the seal packing 39 and the seal packing 40. Leaks into the space. In this space, the liquid flowing from the suction port 22 is also present, and when the seal packing 40 is worn, a part of the liquid further passes through the seal packing 40 and leaks. This liquid flows along the outer peripheral surface of the piston 14 to the shake-off 52, and is blocked by the shake-off 52. Since the shaker 52 is reciprocated with the piston 14, the liquid is discharged to the outside of the shaker 52, and is discharged from the opening 54 of the seal packing retainer 44 to the outside through the flow path 50 of the pump casing 18. Is done.
[0028]
In addition, when the amount of leakage from the seal packing 40 increases, such as when the wear of the seal packing 40 has progressed, the sealing plate 40 is scraped off. That is, the gap between the partition plate 46 and the piston 14 is very small, such as 1.0 mm or less, and more preferably 0.5 mm. The leaked liquid that has thickly adhered to the surface is scraped off by the partition plate 46 by the reciprocating motion of the piston 14. Although it depends on the type of liquid, if the gap between the partition plate 46 and the piston 14 exceeds 1.0 mm, the scraping effect of the partition plate 46 is reduced, which is not desirable. It is not preferable to make the partition plate 46 contact with the partition plate 46 because frictional resistance is increased.
[0029]
The liquid scraped off by the partition plate 46 passes through the notch 48 from the partition plate 46, and is further discharged to the outside of the pump casing 18 through the flow path 50. As a result, the amount of the liquid that reaches the shake-off 52 is reduced, and the liquid is reliably discharged to the outside by the shake-off 52.
[0030]
As described above, in the present embodiment, it is possible to prevent the liquid leaked from the seal packing 40 from entering the drive unit 16, particularly, into the crankcase 30 in two stages of the partition plate 46 and the shaking-off 52. Thus, various adverse effects such as a failure of the reciprocating pump can be prevented.
[0031]
The preferred embodiments of the present invention have been specifically described above, but it is needless to say that the present invention is not limited to the above embodiments.
[0032]
For example, in the above-described embodiment, the cutout 48 is provided in the seal packing retainer 44 to form the flow path 50 for discharging the leaked liquid. However, the through hole may be formed in the seal packing retainer 44 as the flow path 50.
[0033]
In the above embodiment, the partition plate 46 is formed integrally with the seal packing retainer 44, but both may be separate and independent.
[0034]
【The invention's effect】
As described above, in the reciprocating pump of the present invention, even when a large amount of liquid passes through the seal packing retainer and tries to leak to the drive unit side, most of the liquid can be blocked by the partition plate and discharged to the outside. Therefore, it is possible to prevent or suppress the adverse effects when the liquid enters the driving unit.
[0035]
In addition, the cause of the increase in the amount of liquid leakage from the seal packing is mainly due to the wear of the seal packing. However, according to the present invention, even if the wear proceeds, the infiltration of the liquid into the drive unit is prevented and suppressed. Therefore, it is possible to provide a reciprocating pump that can be used for a longer time than before.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a reciprocating pump according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a vertical section of the reciprocating pump of FIG.
FIG. 3 is a perspective view of a seal packing retainer according to the embodiment of the present invention.
FIG. 4 is an enlarged view of a longitudinal section of a conventional reciprocating pump.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Reciprocating pump, 12 ... Cylinder, 14 ... Piston, 16 ... Drive part, 40 ... Seal packing, 44 ... Seal packing retainer, 46 ... Partition plate, 48 ... Notch (communication means), 50 ... Flow path (Communication means) ).

Claims (3)

A cylinder (12);
A piston (14) reciprocally arranged in the cylinder (12);
A drive unit (16) for driving the piston (14);
A seal packing (40) disposed on an inner peripheral surface of an end of the cylinder (12) on the drive unit (16) side and in liquid-tight and slidable contact with an outer peripheral surface of the piston (14);
A cylindrical seal packing retainer (44) for pressing and fixing the seal packing (40);
An annular partition plate (46) provided in the seal packing retainer (44) and coaxially surrounding the piston (14) with a predetermined gap;
Communication means (48, 50) for communicating between the inside and the outside of the seal packing retainer (44) between the seal packing (40) and the partition plate (46). A reciprocating pump characterized in that a reciprocating pump is formed. The reciprocating pump according to claim 1, wherein the partition plate (46) is formed integrally with the seal packing retainer (44). The reciprocating pump according to claim 1 or 2, wherein the gap between the piston (14) and the partition plate (46) is 1.0 mm or less.

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