A pneumatic plunger pump

Abstract

The present invention belongs to the technical field of plunger pumps, and particularly relates to a pneumatic plunger pump, which includes a pump body and a piston rod slidably arranged in the pump body. The lower end of the piston rod extends out of the pump body and is connected to a lower piston slidably arranged in a cylinder barrel. The lower piston divides the inner cavity of the cylinder barrel into an upper chamber and a lower chamber. A sealing plate is connected to the lower end of the piston rod. The sealing plate includes a connecting portion connected to the piston rod at the upper part, a baffle plate at the lower part, and a sleeved portion arranged between the connecting portion and the baffle plate. The lower piston is slidably sleeved on the sleeved portion and is limited between the piston rod and the baffle plate. A liquid passing channel communicating the upper chamber and the lower chamber is provided on the lower piston. During the upward movement of the piston rod, the baffle plate blocks the liquid passing channel; during the downward movement of the piston rod, the baffle plate opens the liquid passing channel. The present invention realizes the function of a check valve through the combined action of the sealing plate and the lower piston during the movement of the piston rod, without additionally installing a separate check valve on the lower piston. The structure is simple, facilitating processing and installation. Moreover, the lower piston occupies a small space and the length of the cylinder barrel is short, effectively saving space.

Description

Technical Field

[0001] The present invention belongs to the technical field of plunger pumps, and particularly relates to a pneumatic plunger pump. Background Art

[0002] A pneumatic plunger pump is a type of plunger pump. It relies on the reciprocating motion of a piston to change the sealed working volume to achieve liquid suction and liquid pressure.

[0003] Chinese invention patent CN103502654B discloses a reciprocating pump valve assembly with heat release, including a fluid container, an air source, a distributor, and a lubricant distribution system of a linear displacement pump. The pump includes an air motor assembly, a pump assembly, and a valve kit. Pressurized air is supplied from an air distribution pipeline to the air motor assembly at the air inlet. The pressurized air drives the air motor assembly in the pump, and the air motor assembly drives the piston in the pump assembly. After driving the air motor assembly, the compressed air leaves the pump at the exhaust port. The air motor assembly includes a cylinder, an air piston, a bottom cover, an outlet housing, and a piston rod. The air motor assembly further includes a piston seal, a cover seal, fasteners, fastener seals, a pilot valve, seals, bearings, U-shaped cup seals, cover fasteners, piston rod fasteners, and piston rod washers. The pump assembly includes a cylinder, an adapter, an intake valve housing, a piston holder, and a pump piston. The pump assembly further includes spring pins, a first spring, a first ball, piston seals, cylinder seals, a second spring, a second ball, and a filter. The pump assembly is a double-acting pump, which, together with check valves, pumps fluid out of the outlet during both the upward and downward strokes of the piston. When the piston rod moves upward during the upward stroke, the piston holder and the pump piston are pulled upward by thread engagement and spring pins. The upward movement of the pump piston creates a vacuum in the cavity of the pump cylinder, which causes the second check valve to open, and fluid from the inlet and the container is suctioned into the cylinder. Specifically, overcoming the force of the spring, the ball is suctioned away from its ball seat in the valve housing by the vacuum. The vacuum generated in the cavity also helps to keep the ball against its ball seat in the piston, which enhances the force of the spring. Any fluid already present in the cavity of the cylinder is prevented from traveling upstream back to the cavity through the first check valve. Specifically, the ball of the first check valve prevents the fluid in the cavity from traveling backward through the hole in the holder. The piston pushes the fluid present in the cavity into the outlet housing, where the fluid is pushed through the outlet. During the downward stroke, the piston pushes the fluid in the cavity into the opening in the piston. When the pressure of the fluid from the cavity pushes the ball away from its ball seat in the piston, the fluid is pushed through the first check valve. After passing through the opening and entering the piston holder, the fluid travels through the hole into the cavity. At the same time, the fluid in the cavity is extruded out of the outlet. Thus, the piston can continue to reciprocate in the cylinder, pumping fluid during both the upward and downward strokes.

[0004] The disadvantages of the above-mentioned pump assembly are as follows: The opening and closing of the opening are controlled by a first check valve composed of a first spring and a first ball arranged on the piston holder and the piston to control the connection and disconnection of the upper and lower chambers in the cylinder. That is, a check valve needs to be installed on the piston, resulting in a complex structure, troublesome processing and installation, and a large space occupied by the piston. Summary of the Invention

[0005] The object of the present invention is to provide a pneumatic piston pump, which realizes the function of the check valve through the combined action of the plugging plate and the lower piston during the movement of the piston rod, without additionally installing a separate check valve on the lower piston, with a simple structure, convenient for processing and installation, and the lower piston occupies a small space and the cylinder barrel is short, effectively saving space.

[0006] The object of the present invention is achieved as follows:

[0007] A pneumatic piston pump includes a pump body and a piston rod slidably arranged in the pump body. The lower end of the piston rod extends out of the pump body and is connected to a lower piston slidably arranged in a cylinder barrel. The lower piston divides the inner cavity of the cylinder barrel into an upper chamber and a lower chamber. A plugging plate is connected to the lower end of the piston rod. The plugging plate includes a connecting portion connected to the piston rod above, a baffle below, and a sleeving portion arranged between the connecting portion and the baffle. The lower piston is slidably sleeved on the sleeving portion and is limited between the piston rod and the baffle. A liquid passing channel communicating the upper chamber and the lower chamber is provided on the lower piston. During the upward movement of the piston rod, the baffle plugs the liquid passing channel; during the downward movement of the piston rod, the baffle opens the liquid passing channel.

[0008] In the above-mentioned pneumatic piston pump, a convex platform protrudes upward in the middle of the lower piston, and the liquid passing channel is located outside the convex platform.

[0009] In the above-mentioned pneumatic piston pump, a chamfer is provided between the lower end face and the outer side wall of the piston rod, and the minimum distance d between the side wall of the liquid passing channel and the axis of the lower piston is greater than the radius of the lower end face of the piston rod.

[0010] In the above-mentioned pneumatic piston pump, a groove communicating the liquid passing channel and the lower chamber is concavely formed in the middle of the lower end face of the lower piston. During the upward movement of the piston rod, the baffle plugs the groove; during the downward movement of the piston rod, the baffle opens the groove.

[0011] In the above-mentioned pneumatic piston pump, the maximum distance D1 between the side wall of the groove and the axis of the lower piston is greater than the maximum distance D2 between the side wall of the liquid passing channel and the axis of the lower piston.

[0012] In the above-mentioned pneumatic piston pump, the liquid passing channel is arranged axially and is circumferentially and evenly distributed with more than two.

[0013] In the above-mentioned pneumatic piston pump, the connection method between the plugging plate and the piston rod: an external thread is provided on the outer ring of the connection part, a threaded hole adapted to the external thread is provided on the piston rod, and the plugging plate is screwed and connected to the piston rod through the external thread and the threaded hole.

[0014] In the above-mentioned pneumatic piston pump, a liquid outlet channel communicating with the upper chamber is provided on the side wall of the pump body, a valve seat is connected to the lower end of the cylinder barrel, an oil suction pipe is connected to the lower end of the valve seat, and a check valve is provided in the valve seat.

[0015] In the above-mentioned pneumatic piston pump, the check valve includes a spring and a steel ball provided on the valve seat.

[0016] In the above-mentioned pneumatic piston pump, a filter screen is provided on the valve seat below the check valve.

[0017] In the above-mentioned pneumatic piston pump, the filter screen is cylindrical or bowl-shaped.

[0018] In the above-mentioned pneumatic piston pump, an O-ring is sleeved on the outer side of the lower piston, and the inner cavity of the cylinder barrel is divided into an upper chamber and a lower chamber by the O-ring through the lower piston.

[0019] In the above-mentioned pneumatic piston pump, an installation groove is provided on the outer side of the lower piston, and the O-ring is arranged in the installation groove.

[0020] The prominent and beneficial technical effects of the present invention compared with the prior art are:

[0021] 1. The present invention blocks and opens the liquid passing channel through the baffle of the plugging plate, and the plugging plate and the lower piston jointly function to realize the function of the check valve during the movement of the piston rod, without additionally installing a separate check valve on the lower piston, with a simple structure, convenient for processing and installation, and the lower piston occupies a small space and the cylinder barrel is short, effectively saving space;

[0022] 2. A boss protrudes upward from the middle of the lower piston of the present invention, and the liquid passing channel is located outside the boss, effectively preventing the piston rod from blocking the liquid passing channel while minimizing the diameter of the lower piston as much as possible;

[0023] 3. A groove communicating the liquid passing channel and the lower chamber is concavely formed in the middle of the lower end face of the lower piston of the present invention, enabling the liquid in the lower chamber to enter the liquid passing channel more smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a cross-sectional view of the present invention;

[0025] Figure 2 is Figure 1 the enlarged view of part A of

[0026] Reference numerals: 1, pump body; 11, liquid outlet channel; 2, piston rod; 21, threaded hole; 22, chamfer; 3, cylinder barrel; 31, upper chamber; 32, lower chamber; 4, lower piston; 41, liquid passing channel; 42, boss; 43, groove; 44, mounting groove; 5, sealing plate; 51, connecting portion; 52, baffle; 53, sleeved portion; 6, valve seat; 7, oil suction pipe; 8, filter screen; 9, O-ring. Detailed implementation manner

[0027] The present invention will be further described below with reference to the accompanying drawings in specific embodiments. Refer to Figure 1 —2:

[0028] A pneumatic plunger pump includes a pump body 1 and a piston rod 2 slidably arranged in the pump body 1. The lower end of the piston rod 2 extends out of the pump body 1 and is connected to a lower piston 4 slidably arranged in a cylinder barrel 3. The lower piston 4 divides the inner cavity of the cylinder barrel 3 into an upper chamber 31 and a lower chamber 32. A sealing plate 5 is connected to the lower end of the piston rod 2. The sealing plate 5 includes a connecting portion 51 located above and connected to the piston rod 2, a baffle 52 located below, and a sleeved portion 53 arranged between the connecting portion 51 and the baffle 52. The lower piston 4 is slidably sleeved on the sleeved portion 53 and is limited between the piston rod 2 and the baffle 52. A liquid passing channel 41 communicating the upper chamber 31 and the lower chamber 32 is provided on the lower piston 4. During the upward movement of the piston rod 2, the baffle 52 blocks the liquid passing channel 41; during the downward movement of the piston rod 2, the baffle 52 opens the liquid passing channel 41. An liquid outlet channel 11 communicating the upper chamber 31 is provided on the side wall of the pump body 1. The lower end of the cylinder barrel 3 is connected to a valve seat 6, the lower end of the valve seat 6 is connected to an oil suction pipe 7, and a check valve is provided in the valve seat 6.

[0029] The working principle of the present invention: As Figure 1 、 2 shown, when the piston rod 2 moves upward, the liquid in the upper chamber 31 is squeezed, and the liquid flows out through the liquid outlet channel 11. At the same time, the pressure in the upper chamber 31 and the vacuum generated in the lower chamber 32 cause the lower piston 4 to move downward relative to the sleeved portion 53 and closely adhere to the baffle 52. The baffle 52 blocks the liquid passing channel 41 to prevent the liquid in the upper chamber 31 from flowing into the lower chamber 32 through the liquid passing channel 41. At this time, due to the vacuum generated in the lower chamber 32, the check valve opens, and the liquid flows into the lower chamber 32 through the oil suction pipe 7 and the valve seat 6; when the piston rod 2 moves downward, the liquid in the lower chamber 32 is squeezed, the check valve closes, the lower piston 4 moves upward relative to the sleeved portion 53, the baffle 52 opens the liquid passing channel 41, and the liquid in the lower chamber 32 flows into the upper chamber 31 through the liquid passing channel 41. At this time, no liquid flows out through the liquid outlet channel 11.

[0030] In the present invention, the liquid passage 41 is blocked and opened by the baffle 52 of the blocking plate 5. The blocking plate 5 and the lower piston 4 cooperate during the movement of the piston rod 2 to achieve the function of a check valve, eliminating the need to additionally install a separate check valve on the lower piston 4. The structure is simple, facilitating processing and installation. Moreover, the lower piston 4 occupies less space and the cylinder barrel 3 has a shorter length, effectively saving space.

[0031] The one-way valve of the present invention is arranged on the cylinder barrel 3 through the valve seat 6. Compared with the existing one-way valve arranged on the oil suction pipe 7, the oil suction pipe 7 is not detachable and replaceable. In the present invention, the oil suction pipe 7 can be replaced according to usage requirements, and the overall length of the product is short.

[0032] Structure of the one-way valve: The one-way valve includes a spring and a steel ball arranged on the valve seat 6. In this embodiment, the spring is a conical spring.

[0033] While minimizing the diameter of the lower piston 4 as much as possible, it effectively prevents the piston rod 2 from blocking the liquid passage 41. As Figure 2 shown, a boss 42 protrudes upward in the middle of the lower piston 4, and the liquid passage 41 is located outside the boss 42.

[0034] To prevent the piston rod 2 from blocking the liquid flowing out of the liquid passage 41, as Figure 2 shown, a chamfer 22 is provided between the lower end face and the outer side wall of the piston rod 2, such that the minimum distance d between the side wall of the liquid passage 41 and the axis of the lower piston 4 is greater than the radius of the lower end face of the piston rod 2.

[0035] To enable the liquid in the lower chamber 32 to enter the liquid passage 41 more smoothly, as Figure 2 shown, a groove 43 communicating with the liquid passage 41 and the lower chamber 32 is formed by concave inward in the middle of the lower end face of the lower piston 4. During the upward movement of the piston rod 2, the baffle 52 blocks the liquid passage 41 by blocking the groove 43; during the downward movement of the piston rod 2, the baffle 52 opens the groove 43.

[0036] Furthermore, the maximum distance D1 between the side wall of the groove 43 and the axis of the lower piston 4 is greater than the maximum distance D2 between the side wall of the liquid passage 41 and the axis of the lower piston 4. In this embodiment, both the groove 43 and the liquid passage 41 are cylindrical.

[0037] To enable the liquid to flow smoothly through the liquid passage 41, the liquid passage 41 is arranged axially and there are more than two circumferentially evenly distributed.

[0038] Connection method between the blocking plate 5 and the piston rod 2: An external thread is provided on the outer circle of the connecting portion 51, and a threaded hole 21 adapted to the external thread is provided on the piston rod 2. The blocking plate 5 is connected to the piston rod 2 by screwing through the external thread and the threaded hole 21.

[0039] Furthermore, an O-ring 9 is sleeved outside the lower piston 4, and the inner cavity of the cylinder barrel 3 is divided into an upper chamber 31 and a lower chamber 32 by the O-ring 9 on the lower piston 4.

[0040] Installation structure of the O-ring: An installation groove 44 is provided outside the lower piston 4, and the O-ring 9 is arranged in the installation groove 44.

[0041] To prevent impurities in the liquid from damaging the seal of the O-ring 9 and reducing its service life, as Figure 1 shown, a filter screen 8 is provided on the valve seat 6 below the one-way valve.

[0042] To increase the filtration area, the filter screen 8 is cylindrical or bowl-shaped.

[0043] The above embodiments are only the preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A pneumatic piston pump, comprising a pump body (1) and a piston rod (2) slidably arranged in the pump body (1). The lower end of the piston rod (2) extends out of the pump body (1) and is connected to a lower piston (4) slidably arranged in a cylinder barrel (3). The lower piston (4) divides the inner cavity of the cylinder barrel (3) into an upper chamber (31) and a lower chamber (32), and is characterized in that: A liquid outlet channel (11) communicating with the upper chamber (31) is provided on the side wall of the pump body (1). The lower end of the cylinder barrel (3) is connected with a valve seat (6), the lower end of the valve seat (6) is connected with an oil suction pipe (7), and a check valve is arranged in the valve seat (6). The lower end of the piston rod (2) is connected with a plugging plate (5). The plugging plate (5) includes a connecting portion (51) connected to the piston rod (2) at the upper part, a baffle (52) at the lower part, and a sleeving portion (53) arranged between the connecting portion (51) and the baffle (52). The lower piston (4) is slidably sleeved on the sleeving portion (53) and is limited between the piston rod (2) and the baffle (52). A liquid passing channel (41) communicating the upper chamber (31) and the lower chamber (32) is provided on the lower piston (4). During the upward movement of the piston rod (2), the baffle (52) plugs the liquid passing channel (41); during the downward movement of the piston rod (2), the baffle (52) opens the liquid passing channel (41). A boss (42) protrudes upward from the middle of the lower piston (4), and the liquid passing channel (41) is located outside the boss (42). A groove (43) communicating the liquid passing channel (41) and the lower chamber (32) is formed by concave inward in the middle of the lower end surface of the lower piston (4). During the upward movement of the piston rod (2), the baffle (52) plugs the groove (43); during the downward movement of the piston rod (2), the baffle (52) opens the groove (43).

2. The pneumatic piston pump according to claim 1, characterized in that: A chamfer (22) is provided between the lower end surface and the outer side wall of the piston rod (2), and the minimum distance between the side wall of the liquid passing channel (41) and the axis of the lower piston (4) is greater than the radius of the lower end surface of the piston rod (2).

3. The pneumatic piston pump according to claim 1, characterized in that: The maximum distance between the side wall of the groove (43) and the axis of the lower piston (4) is greater than the maximum distance between the side wall of the liquid passing channel (41) and the axis of the lower piston (4).

4. The pneumatic piston pump according to claim 1, characterized in that: The liquid passing channel (41) is arranged axially and is circumferentially and evenly distributed with more than two.

5. The pneumatic piston pump according to claim 1, characterized in that: External threads are provided on the outer circle of the connecting portion (51), and threaded holes (21) adapted to the external threads are provided on the piston rod (2). The plugging plate (5) is connected to the piston rod (2) by screwing the external threads with the threaded holes (21).

6. The pneumatic piston pump according to claim 1, characterized in that: A filter screen (8) is provided on the valve seat (6) below the check valve.

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