JPH0821368A - Plunger pump - Google Patents

Abstract

PURPOSE:To guide the liquid entering a cylindrical sleeve made of ceramics from the tip side of the cylindrical sleeve made of ceramics through a pump chamber out of the cylindrical sleeve made of ceramics with a simple structure without difficulties on the safety in a plunger pump provided with a plunger having the cylindrical sleeve made of ceramics. CONSTITUTION:An outer circumferential part of a cylindrical sleeve made of ceramics is sealed by a high pressure seal 44 and a low pressure seal 46 from a pump chamber 16 side. A plurality of through holes 52 are extended in the radial direction, and an end part inside is communicated with the space between the high pressure seal 44 and the low pressure seal 46 in the axial direction, while an end part outside is communicated with a passage part between a suction port 18 and a suction valve 22 through a communicating passage 54. A plurality of through holes 58 are formed so as to communicate the inside of the cylindrical sleeve 36 made of ceramics with the outside thereof within the reciprocating range of the plunger 26 to be kept between the high pressure seal 44 and the low pressure seal 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plunger pump having a plunger with a sleeve, and more particularly to a plunger pump capable of coping with intrusion of liquid from a pump chamber into the sleeve.

[0002]

2. Description of the Related Art In a plunger pump, a cylindrical sleeve made of ceramic is put on the tip side of the plunger to improve wear resistance and chemical resistance of the plunger. Then, the plug is screwed onto the tip of the stud bolt in the ceramic cylindrical sleeve, and the ceramic cylindrical sleeve is tightened and fixed to the plunger body. The plug also has a function of preventing the liquid in the pump chamber from entering the ceramic cylindrical sleeve and corroding the stud bolt in the ceramic cylindrical sleeve, and is provided with a predetermined seal. The front end side opening of the ceramic cylindrical sleeve is closed.

However, if the sealing property between the plug and the ceramic cylindrical sleeve deteriorates with the passage of time,
The liquid in the pump chamber enters the ceramic cylindrical sleeve,
In addition to the corrosion of the metal portion described above, this causes various obstacles such as freezing and breakage of the ceramic cylindrical sleeve due to an increase in the internal pressure of the ceramic cylindrical sleeve.

Therefore, in the plunger pump disclosed in Japanese Utility Model Publication No. 4-33966, a discharge passage is formed at the base end side of the ceramic cylindrical sleeve, and the liquid that has entered the ceramic cylindrical sleeve is discharged to the outside through the discharge passage. I try to discharge it.

[0005]

[Problems to be Solved by the Invention]
In the plunger pump disclosed in the publication, if the liquid is an agricultural chemical or the like, if it is discharged to the outside as it is, it may be harmful to the human body.Therefore, it is necessary to strictly manage the liquid after discharge, and the management is complicated. Become.

In Japanese Patent Publication No. 58-55821 and Japanese Utility Model Publication No. 49-40803, the liquid in the pump chamber is supplied to the proximal end side of the plunger through a seal that seals the peripheral portion of the plunger against the reciprocating movement of the plunger. In order to deal with leakage to the inside of the cylinder, it is disclosed that the base end side of the seal is connected to the suction port and the leaked liquid is sucked back into the pump chamber. No mention is made of the structure for delivering the liquid.

An object of the present invention is to provide a plunger pump which can draw out the intruding liquid into the sleeve of a plunger with a sleeve with a simple structure without any hindrance to safety after the drawing.

[0008]

The present invention will be described using reference numerals in the drawings corresponding to the embodiments. In the plunger pump (10) of the present invention, the plunger (26) includes the pump chamber (1
6) A sleeve (36) reaching the inside of the plunger (26) and forming the peripheral portion of the plunger (26), and a plug (38) closing the front end side opening of the sleeve (36). High pressure seal (44) and low pressure seal
(46) is arranged in order from the pump chamber (16) side in the axial direction of the plunger (26), and slidably contacts the outer peripheral portion of the sleeve (36) on the inner peripheral side to seal the pump chamber (16). . Outlet passage (52,
54) has a sleeve (3) between the high pressure seal (44) and the low pressure seal (46) in the axial direction of the plunger (26) at one end side.
It faces the outer periphery of 6) and communicates with the suction port (18) at the other end. The through hole (58) is located in the axial direction of the plunger (26) at a position between the high pressure seal (44) and the low pressure seal (46).
The inside and outside of (36) communicate with each other.

[0009]

[Function] Due to the progress of use, etc., the sleeve (36) and plug (38)
If the sealing property between the sleeve and the pump chamber (16) deteriorates, the liquid in the pump chamber (16) will pass through the gap between the sleeve (36) and the plug (38).
Invade inside. On the other hand, the suction port (18) is connected to the plunger pump (1
In the suction stroke of (0), the suction force from the pump chamber (16) is received, and this suction force is also transmitted to the outlet passages (52, 54). sleeve
The through hole (58) formed in (36) communicates with the outlet passage (52, 54), and the suction port (1) is transmitted through the outlet passage (52, 54).
The suction force from the 8) side is further transmitted into the sleeve (36).
In this way, the invading liquid in the sleeve (36) is sucked by the suction force from the suction port (18), is led out to the outlet passages (52, 54) through the through hole (58), and is further led out. It is guided from (52, 54) toward the suction port (18) and is again sucked into the pump chamber (16) from the suction port (18) side.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a vertical sectional view of the plunger pump 10.
The plunger pump 10 is equipped in, for example, a power sprayer used in a pesticide sprayer in a field, and is of a triple type (three pumps are arranged in parallel and driven by a common crankshaft). Has become. The crankcase 12 has a manifold 14 joined to the front end side thereof, and the pump chamber 16 is formed in the manifold 14. Inlet 18 and outlet 20 are manifolds 14
The suction valve 22 and the discharge valve 24, which are respectively provided in the lower part and the upper part of the manifold, allow only one-way liquid flow from the suction port 18 to the pump chamber 16 and from the pump chamber 16 to the discharge port 20, respectively. It is fitted into the inside of the manifold 14 and is prevented from coming off the manifold 14 by the plugs 23 and 25.

The plunger 26 has a crosshead 28, a base member 30, and a ceramic cylindrical sleeve 36 in order from the base end side. Crosshead 28 is a crankcase
The guide 26 is fitted into the guide 27 of the 12 and guided in the axial direction, and is connected to the crankshaft (not shown) in the crankcase 12 via a connecting rod (not shown). The plunger 26 is rotated as the crankshaft rotates. Reciprocates in the axial direction. The circular boss 32 is formed so as to be raised at the center of the end surface on the tip side of the base side member 30, and the stud bolt 34 is coaxial with the ceramic cylindrical sleeve 36 by screwing the base end into the circular boss 32. It extends in a ceramic cylindrical sleeve 36. The ceramic cylindrical sleeve 36 fits into the circular boss 32 at the proximal end and the plug 38
Is inserted into the front end side opening of the ceramic cylindrical sleeve 36, screwed into the front end portion of the stud bolt 34, and the ceramic cylindrical sleeve 36 is brought into contact with the base end side end surface at the flange portion to form the ceramic cylindrical sleeve. 36 is fastened to the base member 30.

The oil seal 40 is disposed on the tip side of the crosshead 28 and slidably contacts the base side member 30 on the inner peripheral side to prevent leakage of lubricating oil from the crankcase 12. The collar 41 and the seal case 42 are arranged on the pump chamber 16 side and the crankcase 12 side, respectively, with their center lines aligned, and are axially butted against each other. Color
41 presses and fixes the high-pressure seal 44 on the front end side, and the seal case 42 has a low-pressure seal 46 fixed on the inner peripheral side of the rear end. The oil pan 48 is disposed below the plunger 26 at the boundary between the crankcase 12 and the manifold 14,
Stores a predetermined amount of lubricating oil. Felt packing 50
Is fixed in the axial direction of the plunger 26 at the upper end portion, penetrates the ceramic cylindrical sleeve 36 while slidingly contacting the ceramic cylindrical sleeve 36, and hangs down into the oil pan 48 at the lower end portion. Cylinder sleeve made of ceramic that absorbs the lubricating oil inside by suction
Supply to the outer circumference of 36.

The collar 41 is provided with a plurality of through holes 52 at the end on the side where the seal case 42 abuts, and these through holes 52 are
They are arranged at equal angular intervals in the circumferential direction, extend in the radial direction from the through holes 52, and the ends inside the radial direction are the collar 41 and the seal case.
It communicates with the annular space between the inner circumference of 42 and the outer circumference of the ceramic cylindrical sleeve 36. The communication passage 54 is connected to the manifold 14
Extends in the vertical direction, communicates with the radially outer ends of the through holes 52 on the upper end side, and the suction port 18 and the suction valve 22 on the lower end side.
Is in communication with.

2 and 3 show a ceramic cylindrical sleeve.
FIG. 3 is a vertical cross-sectional view of 36 and a view of the ceramic cylindrical sleeve 36 seen from one end side in the axial direction. The cylindrical hole 56 penetrates the ceramic cylindrical sleeve 36, and a stud bolt 34 (FIG. 1) is inserted inside the cylindrical hole 36 with a proper interval in the radial direction between the stud bolt 34 and the stud bolt 34. The total of four through holes 58 are 9 in the circumferential direction.
The ceramic cylindrical sleeves 36 are arranged at 0 ° intervals and penetrate through the side wall of the ceramic cylindrical sleeve 36 in the radial direction.
Communicate with each other inside and outside. The through hole 58 is located at a position substantially at the center of the ceramic cylindrical sleeve 36 in the axial direction, and at this position, the through hole 58 is located at both ends of the reciprocating range of the plunger 26. Held in a position between.

Returning to FIG. 1, a ceramic cylindrical sleeve.
O-rings 60 and 62 are fitted in the annular grooves at the periphery of the plug 38 and the circular boss 32, respectively, in order to maintain the seal inside the ceramic cylindrical sleeve 36 at both axial ends of 36.

The operation of the embodiment will be described. When the sealability of the O-ring 60 deteriorates during use of the plunger pump 10, the liquid in the pump chamber 16 passes through the O-ring 60 and enters the ceramic cylindrical sleeve 36. On the other hand, communication passage 54
The suction port 18 side receives the suction force from the pump chamber 16 in the suction stroke of the plunger pump 10. The through hole 58 formed in the ceramic cylindrical sleeve 36 is maintained at a position between the high pressure seal 44 and the low pressure seal 46 in the axial direction of the plunger 26 in the reciprocating range of the plunger 26, and the outer periphery of the ceramic cylindrical sleeve 36. The surface communicates with the annular space between the collar 41 and the inner peripheral surface of the seal case 42. Thus, the suction force from the suction port 18 side acts on the inside of the ceramic cylindrical sleeve 36 via the communication passage 54 and the through hole 52, and the invading liquid inside the ceramic cylindrical sleeve 36 is sucked on the suction port 18 side. It is sucked by force and is led out from the through hole 58 into the annular space between the inner peripheral surfaces of the collar 41 and the seal case 42 and the outer peripheral surface of the ceramic cylindrical sleeve 36. Then, in the annular space, the high pressure seal 44
The liquid merges with the liquid leaking from the pump chamber 16 through the inner peripheral side thereof, and is guided to the suction port 18 side through the through hole 52 and the communication passage 54 together with the liquid leaking from the high pressure seal 44. Then, it merges with the new suction liquid from the suction port 18 and is sucked again into the pump chamber 16 through the suction valve 22.

[0017]

According to the present invention, the liquid in the pump chamber, which has entered the sleeve of the plunger with the sleeve from between the sleeve and the plug, is discharged from the inside of the sleeve through the through hole formed in the sleeve, and the pump chamber. Since it will be sucked again from the suction port side to the
It can be processed by a simple structure without any safety problem, and complicated safety management after derivation can be omitted.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a plunger pump.

FIG. 2 is a vertical sectional view of a ceramic cylindrical sleeve.

FIG. 3 is a diagram of a ceramic cylindrical sleeve as viewed from one axial side.

[Explanation of symbols]

 10 Plunger Pump 16 Pump Chamber 18 Suction Port 26 Plunger 36 Ceramic Cylindrical Sleeve (Sleeve) 38 Plug 44 High Pressure Seal 46 Low Pressure Seal 52 Through Hole (Derivation Passage) 54 Communication Passage (Derivation Passage)

Claims (1)

[Claims] 1. A sleeve (3) in which a plunger (26) reaches into a pump chamber (16) and forms a peripheral portion of the plunger (26).
6) and a plug (38) that closes the front end side opening of the sleeve (36), and has a high pressure seal (44) and a low pressure seal (46).
Are arranged in this order from the pump chamber (16) side in the axial direction of the plunger (26), and are in sliding contact with the outer peripheral portion of the sleeve (36) on the inner peripheral side to seal the pump chamber (16). Done,
The outlet passages (52, 54) have, on one end side, the high pressure seal (44) and the low pressure seal (4) in the axial direction of the plunger (26).
6) facing the outer peripheral portion of the sleeve (36) and communicating with the suction port (18) at the other end, and the through hole (58) is the high pressure seal in the axial direction of the plunger (26). (44) and the low-pressure seal
A plunger pump characterized in that the inside and outside of the sleeve (36) are communicated with each other at a position between the sleeve and the (46).