JPH01151787A - Plunger pump - Google Patents

Abstract

PURPOSE:To improve durability of a plunger by arranging a partition wall encapsulating pressure transmission fluid in a fluid path in front of the top dead point of the plunger such that it will partition into plunger side, suction and delivery valve body sides. CONSTITUTION:Upon reciprocal sliding of a plunger 14 through rotary driving of a crankshaft, lubricant in a cylinder 13 is compressed to increase pressure of fluid in a fluid path 12 through an elastically deformable partition wall 23 encapsulating pressure transmission fluid, and thereby a suction valve body 19 closes to deliver fluid in the fluid path 12 through a delivery valve body 22. When negative pressure is produced in the cylinder 13 due to returning motion of the plunger 14, the delivery valve body 22 closes to suck fluid through the suction valve body 19 into a partition wall section 23. By such arrangement, abrasion of the plunger 14 and the cylinder 13 due to a solid mass can be prevented, and since pressure functioning onto the plunger 14 is relieved through the partition wall 23 even when the pressure of the fluid is abnormally high, durability of driver is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a reciprocating sliding plunger pump for pumping fluids such as cement milk, medicinal solutions, and fluid foods.

(Prior art) -C, this type of plunger pump has a cylindrical shape in which a suction valve element and a discharge valve element are provided in the fluid passage, and a plunger is housed in the fluid passage between the two valve elements so as to be slidable back and forth. The cylinder is facing forward, and the suction valve body and discharge valve body are controlled to open and close alternately based on pressure fluctuations in the cylinder by reciprocating drive of the plunger, and fluid in the fluid passage is sucked from the suction valve body and discharged from the pressure valve body. However, if the fluid to be fed contains solids such as cement milk, the solids may get caught between the plunger and the cylinder, causing the plunger to prematurely close. There was a problem that it would wear out.

In order to solve this problem, there is a plunger in which at least the outer circumferential surface of the plunger is made of ceramic to prevent the plunger from being worn out.

(Problems to be Solved by the Invention) As mentioned above, in the reciprocating sliding type plunger pump of the conventional structure in which the outer peripheral surface of the plunger is formed of ceramics, first of all, ceramics are brittle and easily chipped. There was a problem that the method was expensive and the entire device was expensive.

Moreover, even if the outer circumferential surface of the plunger is made of ceramic, it is not possible to prevent solid objects from getting caught between the plunger and the cylinder, and the inner circumferential surface of the cylinder wears out, causing the plunger to deteriorate. There was also the problem that the work was more extensive and expensive than replacing it.

In addition, because the plunger is structured to directly press the fluid to be delivered, if the inner thickness of the cylinder increases abnormally due to, for example, a blockage on the discharge side, this abnormal pressure will directly act on the drive device through the plunger. There was a problem in that the durability of the drive device was reduced.

The present invention was proposed in view of such problems, and an object of the present invention is to provide a pump that is inexpensive and has excellent durability.

(Means for Solving the Problems) In order to achieve the above object, the plunger pump according to the present invention includes a suction valve body and a discharge valve body in a fluid passage, and a fluid passage between the two valve bodies. A cylindrical cylinder that houses a plunger in a reciprocating manner faces the cylinder, and an elastically deformable partition wall that seals a pressure transmitting fluid is placed in the cylinder or fluid passage ahead of the top dead center of the plunger. It is characterized in that it is provided in a state where it is partitioned off from both valve body side fluid passages.

(Function) When the plunger slides back and forth inside the cylinder, high pressure is created in the cylinder due to the forward movement, and when this pressure acts on the fluid in the fluid passage through the partition wall that seals the fluid, the suction valve body Since the discharge valve body opens at the same time as the valve closes, fluid is discharged and fed from the discharge valve body.

Next, when the plunger moves back and the cylinder becomes negative pressure,
This negative pressure is transmitted to the fluid in the fluid passage through the fluid-tight partition wall, and the discharge valve body is closed and the suction valve body is opened, and the fluid to be supplied is sucked into the partition wall portion. It is.

Even when the plunger is driven back and forth, the partition wall keeps the plunger isolated from the fluid to be fed, so solids in the fluid to be fed get caught between the plunger and the cylinder. is prevented.

Furthermore, even if the pressure of the fluid to be fed rises abnormally, the pressure transmitting fluid sealed inside the elastic membrane of this partition wall acts to relieve the pressure and protect the driving means of the plunger. be.

(Example) Hereinafter, an example of a plunger pump according to the present invention will be described based on the drawings.

FIG. 1 shows a partially cutaway side view of a plunger pump, and this plunger pump 1 has a pump casing 2.
and a pump head 3 attached to the left end of the pump casing 2.

A crankcase 4 is formed in the right half of the pump casing 2. A crankshaft 5 is rotatably supported on the side wall of the crankcase 4, and a piston 6 is provided at the left end of the crankcase 4. The Eleap 7, which slidably houses the ELEAP 7, is attached.

The piston 6 and the crankshaft 5 are connected by a connecting rod 8, and the crankshaft
When a drive gear 10 meshing with a driven gear 9 attached to the piston 1 is rotated, the crank motion of the crankshaft 5 causes the piston 6 to slide from side to side in the figure via the connecting rod 8.

In this way, when the piston 6 slides left and right, this movement is transmitted via the coupling 1) to the plunger 14 in the cylinder 13 that communicates with the fluid passage 12, which will be described later, and this plunger 14 is driven to slide. ing.

The pump head 3 has a suction port 15 formed on the lower surface of the pump head 3 as shown in FIGS. 1 and 2.
A fluid passage 12 is formed in the shape of a crank and communicates between the pump head 3 and a discharge port 16 formed in the upper part of one side of the pump head 3. The fluid passage 12 near the suction boat 15 has a ball 17 and a valve in contact with the fluid passage 12. Suction valve body 1 consisting of seat 18
9 is provided, and a discharge valve body 22 consisting of a ball 20 and a valve seat 21 with which the ball 20 comes into contact is provided in the fluid passage 12 near the discharge boat 16.

Further, the fluid passage 1 between the suction valve body 19 and the discharge valve body 22
A part of the fluid passage 12 is branched out from the cylinder 2 so as to communicate with the cylinder 13 which slidably houses the plunger 14.

A partition wall 23 is formed between the branched fluid passage 12 and the cylinder 13.

That is, as shown in FIGS. 2 and 3, the partition wall 23 is provided with partition wall storage blocks 25 and 26 that can be divided into right and left sides between the cylinder forming block 24 and the pump head 3. A spherical partition storage chamber 27 is formed inside the blocks 25 and 26, and two elastic thin-walled partitions 28 are placed opposite each other and their peripheral portions 28a are joined together to fill the interior with a liquid such as silicone oil (pressure transmission fluid). ) 29, and the peripheral edge portion 28a of the partition wall 23 is sandwiched and fixed between the partition wall storage blocks 25 and 26 to partition the fluid passage 12 portion and the cylinder 13. It is composed.

The cylinder 13 separated from the fluid passage 12 by the partition wall 23 is filled with lubricating oil from an oil filling port 30 formed in the cylinder forming block 24, and this oil filling port 30 is filled with a sealing plug 31. is sealed with.

In the plunger pump l configured as described above, when the crankshaft 5 is rotationally driven by the drive device and the plunger 14 slides back and forth inside the cylinder 13 via the connecting rod 8 and the piston 6, the plunger 14 moves back and forth within the cylinder 13. The lubricating oil in 13 is compressed, and this pressure acts on the fluid in fluid passage 12 via fluid-tight partition wall 23 .

When the pressure of the fluid in the fluid passage 12 becomes high, the suction valve body 19 closes and the discharge valve body 22 opens, and the fluid in the fluid passage 12 is discharged and fed from the discharge valve body 22.

Next, when the inside of the cylinder 13 becomes negative pressure due to the return movement of the plunger 14, this negative pressure is transmitted to the fluid in the fluid passage 12 via the liquid-sealed partition wall 23, and, contrary to the above, When the discharge valve body 22 is closed, the suction valve body 19 is opened, and the fluid to be fed from the suction valve body 19 is sucked into the partition wall 23 portion.

Since the plunger 14 is kept isolated from the fluid to be fed by the partition wall 23 even when the plunger 14 is driven back and forth, the solids in the fluid to be fed are separated from the plunger 14 and the cylinder 13. In addition, even if the pressure of the fluid to be delivered increases abnormally, the elastic diaphragm 28 of this partition wall 23 and the limbs 29 enclosed within it relieve the pressure. Therefore, it also functions to protect the driving means of the piston 6.

Further, the lubricating oil filled in the plunger 14 partitioned by the partition wall 23 maintains smooth sliding of the plunger 14 and prevents the cylinder 13 and the plunger 14 from being worn out.

In the above embodiment, silicone oil is sealed in the partition wall 2-3 as the pressure transmitting fluid, but other fluids or fluids such as air can be selected depending on its compressibility.

Further, in the embodiment described above, the partition wall 23 is formed by placing two thin elastic diaphragms 28 facing each other, joining their peripheral portions 28a, and sealing a liquid 29 such as silicone oil inside. Of course, three or more diaphragms 28 may be provided, and it goes without saying that each diaphragm 28 may be fixed to the partition wall storage blocks 25 and 26, respectively. It is.

(Effects of the Invention) As described above, the present invention allows the pressure fluctuations generated in the cylinder due to the reciprocating motion of the plunger to act on the fluid to be delivered through the partition wall in which the fluid is sealed in an elastic membrane material. Therefore, there is no need to use an expensive plunger pump such as a ceramic plunger, and the entire device can be made cheaper.

Moreover, since the plunger does not come into direct contact with the fluid to be fed, solid matter contained in the fluid to be fed will not get caught between the plunger and the cylinder, thereby preventing wear on the plunger and cylinder as much as possible. can greatly improve its durability.

Furthermore, even if a blockage occurs on the discharge side and the pressure of the fluid to be delivered increases abnormally, this abnormally high pressure is relieved by the elastic diaphragm and the pressure transmission fluid sealed inside, and acts on the plunger. Therefore, abnormally high pressure is prevented from directly acting on the drive device that drives the plunger, and the durability of the drive device can be greatly improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; Fig. 1 is a partially cutaway side view of a plunger pump, Fig. 2 is a longitudinal side view of the pump head, and Fig. 3 is an exploded perspective view of the main parts. . 1... Plunger pump, 12... Fluid passage, 13
... Cylinder, 14... Plunger, 19... Suction valve body, 22... Discharge valve body, 23... Division wall, 29
...Pressure transmission fluid.

Claims (3)

[Claims] (1) A suction valve body and a discharge valve body are provided in the fluid passage, and a cylindrical cylinder that houses a plunger so as to be able to slide back and forth faces the fluid passage between both valve bodies, and the top dead center of the plunger is A plunger pump characterized in that an elastically deformable partition wall that seals a pressure transmitting fluid in a cylinder or a fluid passage located further forward is provided in a state that partitions the inside of the plunger side cylinder and both valve body side fluid passages. (2) The plunger pump according to claim 1, wherein a plunger-side cylinder partitioned by a diaphragm is filled with lubricating oil. (3) A patent in which a plurality of elastic thin films are provided in a cylinder or a fluid passage so as to be opposed to each other with spaces formed between them, and the space between the elastic films is filled with a pressure transmitting fluid to form a partition wall. A plunger pump according to claim 1.