PNEUMATIC AUTOMATIC REVERSING TRANSFER PUMP

Abstract

The utility model discloses a pneumatic automatic reversing feeding pump, which belongs to the technical field of pneumatic pumps, and it comprises a pneumatic part, a connecting part, and a pumping part. The pneumatic part adopts the design structure of a square cylinder; the design structure of a square integrated reversing valve and valve plate; the spherical piston rod connection structure; the pneumatic part and the hydraulic part are easy to install and dismantle with the clamp design structure. The hydraulic part includes a bung adapter assembly, a pump body, a up suction tube, a lower suction tube, an intake valve, and other related parts. It has a reasonable structural design, simple operation, seamless transition between forward and reverse strokes, easy installation, and maintenance, better sealing effect, strong reliability, and can be applied to various working environments

Claims

1. A pneumatic pump assembly for liquid products, the pneumatic pump assembly comprising: a cylinder; a cylinder cap coupled to a top of the cylinder; a cylinder base coupled to a bottom of the cylinder; a piston head of a piston slidably received within the cylinder, a piston rod of the piston passes through the cylinder base, wherein a top of the piston head and the cylinder cap form an upper chamber, wherein a bottom of the piston head and the cylinder base form a lower chamber; an upper pilot valve disposed in the cylinder cap, wherein the upper pilot valve comprises a first spring and a first gasket, wherein the first spring in an extended state results in closing of the upper pilot valve and the first spring in a compressed state results in opening of the upper pilot valve; a lower pilot valve disposed in the cylinder base, wherein the lower pilot valve comprises a second spring and a gasket, wherein the spring in an extended state results in closing of the upper pilot valve and the spring in a compressed state results in opening of the upper pilot valve; and a directional control valve configured to direct air from a pressurized air source to the upper chamber and the lower chamber, the directional control valve configured to switch between an up mode and a down mode by actuation of the upper pilot valve and the lower pilot valve, wherein the air is directed to the upper chamber in the up mode and to the lower chamber in the down mode, the directional control valve comprises: reversing valve shaft that has an upper shaft head and a lower shaft head, wherein the reversing valve shaft is configured to be driven in a reciprocating manner by air under pressure for directing the air to the upper chamber and the lower chamber, wherein the movement of the reversing valve shaft is controlled by the upper pilot valve and the lower pilot valve; and a housing encasing an upper cavity and a lower cavity, wherein the upper shaft head moves within the upper cavity and the lower shaft head moves within the lower cavity, wherein a first air path connects the upper cavity to the upper pilot valve and a second air path connects the lower cavity to the lower pilot valve, wherein the upper cavity and the lower cavity have an air input port for filling air under pressure into the upper cavity and the lower cavity, wherein the air under pressure in the upper cavity and the lower cavity is configured to cause a valve core to press the gasket of each of the upper pilot valve and the lower pilot valve.

2. The pneumatic pump assembly according to claim 1, wherein the upper pilot valve is configured to be actuated by the piston head during upward movement of the piston head, when the piston head strikes the upper pilot valve.

3. The pneumatic pump assembly according to claim 2, wherein the actuation of the upper pilot valve switches the directional control valve to the up mode.

4. The pneumatic pump assembly according to claim 3, wherein the lower pilot valve is configured to be actuated by the piston head during downward movement of the piston head, when the piston head strikes the lower pilot valve.

5. The pneumatic pump assembly according to claim 4, wherein the actuation of the lower pilot valve switches the directional control valve to the down mode.

6. The pneumatic pump assembly according to claim 5, wherein the directional control valve is coupled to the cylinder cap and the cylinder base through a manifold.

7. (canceled)

8. The pneumatic pump assembly according to claim 7, wherein a lower air intake port is disposed in the cylinder base and the air from the directional control valve is received through a lower air duct.

9. The pneumatic pump assembly according to claim 8, wherein an upper air intake port is disposed in the cylinder cap and the air from the directional control valve is received through an upper air duct.

10. The pneumatic pump assembly according to claim 5, wherein the pneumatic pump assembly comprises an air motor part and a pump part, the air motor part comprises the lower pilot valve, the upper pilot valve, the piston, the directional control valve, and the cylinder.

11. The pneumatic pump assembly according to claim 10, wherein the pump part is removably coupled to the air motor part through a clamp.

12. The pneumatic pump assembly according to claim 11, wherein the piston of the air motor part is coupled to a second piston of the pump part through a piston rod coupler.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying Figures, which are incorporated herein, form part of the specification and illustrate embodiments of the present invention. Together with the description, the Figures further explain the principles of the present invention and enable a person skilled in the relevant arts to make and use the invention.

[0014] FIG. 1 is a schematic diagram of a pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0015] FIG. 2 is a schematic diagram showing the clamp of the pneumatic transfer pump system in a partially open state for unclamping, according to an exemplary embodiment of the present invention.

[0016] FIG. 3 is a partially exploded view of a coupling part of the pneumatic transfer pump system showing the flanged hollow ring, the flat disk, and the clamp, according to an exemplary embodiment of the present invention.

[0017] FIG. 4 shows an enlarged view of a cylinder of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0018] FIG. 5 shows a coupler of the piston rod of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0019] FIG. 6 is an exploded view of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0020] FIG. 7 shows an enlarged view of a portion of the exploded view shown in FIG. 6, according to an exemplary embodiment of the present invention.

[0021] FIG. 8 is an exploded view of a pilot valve of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0022] FIG. 9 is an exploded view of the cylinder cap and the pilot valve of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0023] FIG. 10 shows an enlarged view of a portion of the exploded view shown in FIG. 6, according to an exemplary embodiment of the present invention.

[0024] FIG. 11 shows an enlarged view of a portion of the exploded view shown in FIG. 6, according to an exemplary embodiment of the present invention.

[0025] FIG. 12 is a schematic diagram of the cylinder, the manifold, and the directional control valve showing the upward stroke of the piston, according to an exemplary embodiment of the present invention.

[0026] FIG. 13 is a schematic diagram illustrating the downward stroke of the piston, according to an exemplary embodiment of the present invention.

[0027] FIG. 14 is a 3D diagram of the cylinder cap of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0028] FIG. 15 is a 3D diagram of the cylinder base of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0029] FIG. 16 is a 3D diagram of the manifold of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0030] FIG. 17 is a 3D view of the directional control valve of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0031] FIG. 18 is an isometric 3D diagram of a directional control valve of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0032] FIG. 19 is a 3D view of a directional control valve cover of the pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0033] FIG. 20 shows a pneumatic transfer pump system, according to an exemplary embodiment of the present invention.

[0034] FIG. 21 is a schematic diagram of the pilot valve controlling the directional valve, according to an exemplary embodiment of the present invention.

[0035] FIG. 22 shows the road map of the intake and exhaust of the cylinder, according to an exemplary embodiment of the present invention.

[0036] FIG. 23 is a road map for the directional valve to control the exhaust, according to an exemplary embodiment of the present invention.

[0037] FIG. 24 shows movement of the piston, according to an exemplary embodiment of the present invention

[0038] FIG. 25 shows the piston completing the reverse rotation, according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

[0039] Subject matter will now be described more fully hereinafter with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, specific exemplary embodiments. Subject matter may, however, be embodied in a variety of different forms and, therefore, covered or claimed subject matter is intended to be construed as not being limited to any exemplary embodiments set forth herein; exemplary embodiments are provided merely to be illustrative. Likewise, the reasonably broad scope for claimed or covered subject matter is intended. Among other things, for example, the subject matter may be embodied as methods, devices, components, or systems. The following detailed description is, therefore, not intended to be taken in a limiting sense.

[0040] The word exemplary is used herein to mean serving as an example, instance, or illustration. Any embodiment described herein as exemplary is not necessarily to be construed as preferred or advantageous over other embodiments. Likewise, the term embodiments of the present invention does not require that all embodiments of the invention include the discussed feature, advantage, or mode of operation.

[0041] The terminology used herein is to describe particular embodiments only and is not intended to be limiting of embodiments of the invention. As used herein, the singular forms a, an, and the are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms comprises, comprising,, includes and/or including, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0042] The following detailed description includes the best currently contemplated mode or modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense but is made merely to illustrate the general principles of the invention since the scope of the invention will be best defined by the allowed claims of any resulting patent.

REFERENCE NUMERALS

[0043] Directional control valve 1 [0044] Manifold 2 [0045] Pilot valve 3 [0046] Cylinder Cap 4 [0047] Cylinder 5 [0048] Cylinder Base 6 [0049] Piston rod coupler 7 [0050] Flanged hollow ring 8 [0051] Clamp 9 [0052] Bung adapter 10 [0053] Pump body 11 [0054] Up suction tube 12 [0055] Lower suction tube 13 [0056] Intake valve 14 [0057] Flat disk 15 [0058] Screw 1a [0059] Set screw 1b [0060] Valve cover 1c [0061] Socket Head Cap Screw 1d [0062] O-Ring 1e [0063] Valve block 1f [0064] Set screw 1g [0065] Socket Head Cap Screw 1h [0066] Gasket 1i [0067] Support frame 1j [0068] reversing valve shaft 1k [0069] Gasket 1l [0070] O-Ring 1m [0071] Shaft head 1n [0072] O-ring 1o [0073] Upper shaft head Assy 1o(1) [0074] Lower shaft head Assy 1o(2) [0075] Valve cover 1p [0076] O-ring 1q [0077] Manifold plate 2a [0078] Set screw 2b [0079] Set screw 2c [0080] O-Ring 2d [0081] O-Ring 2e [0082] valve cap 3a [0083] scaling ring 3b [0084] return spring 3c [0085] valve core 3d [0086] Gasket 3e [0087] O-ring 3f [0088] cylinder cap 4a [0089] O-ring 4b [0090] Cylinder 5a [0091] piston 5b [0092] O-ring 5c [0093] Piston rod 5d [0094] cylinder base 6a [0095] Tie rod 6b [0096] Flanged hollow ring 8a [0097] Flat disc 8b [0098] Packing nut 8c [0099] Seal Retainer 8d [0100] V-packing 8e [0101] Seal Expander 8f [0102] Wiper 8g [0103] Air inlet 1-1 [0104] Upper pilot valve inlet 1-2 [0105] Lower pilot valve inlet 1-3 [0106] Downstroke air inlet 1-4 [0107] Upstroke air inlet 1-5 [0108] Upstroke exhaust port 1-6 [0109] Downstroke exhaust port 1-7 [0110] Main exhaust port 1-8 [0111] Pilot valve inlet 1-9 [0112] Pilot valve inlet 1-10 [0113] Upstroke air inlet 2-1 [0114] Downstroke air inlet 2-2 [0115] Pilot valve inlet 2-3 [0116] Pilot valve inlet 2-4 [0117] Pilot valve inlet 2-5 [0118] Upstroke air inlet 2-6 [0119] Downstroke air inlet 2-7 [0120] Pilot valve inlet 2-8 [0121] upper pilot valve 3-1 [0122] pilot valve 3-2 [0123] Pilot valve seat 4-1 [0124] Air inlet 4-2 [0125] Pilot valve inlet 4-3 [0126] Pilot valve outlet 4-4 [0127] Pilot valve seat 6-1 [0128] Air inlet 6-2 [0129] Pilot valve inlet 6-3 [0130] Pilot valve outlet 6-4

[0131] Disclosed is a pneumatic transfer pump system that can be used to transfer liquid products, such as plastic material. The disclosed system can be used to transfer/pump plastic material, such as polyurethane in industrial processes. The pneumatic transfer pump system can be adapted to the changes in the viscosity of the liquid to be transferred without changing pneumatic cylinders of different sizes. This is achieved by incorporating an automated reversing function in combination with a pneumatic cylinder that allows adapting to the changes in viscosity of the liquid.

[0132] Referring to FIG. 1 which shows an exemplary embodiment of the pneumatic transfer pump system. The pneumatic transfer pump system includes a cylinder, a cylinder cap secured to the cylinder at the top thereof, and a cylinder base secured to the cylinder at the base thereof. The cylinder cap and cylinder base can be secured to the cylinder using suitable fasteners, such as bolts, however, any suitable fastening mechanism is within the scope of the present invention. Moreover, the cylinder cap and the cylinder base can be secured to the cylinder using different fastening mechanisms. A directional control valve 1 can be connected to the cylinder cap and cylinder base through manifold 2, while realizing the intake, exhaust, and automatic reversing functions. The cylinder with the manifold forms an air motor part of the pneumatic transfer pump system.

[0133] The air motor part of the pneumatic transfer pump system can be connected to a pump part of the pneumatic transfer pump system through a piston rod. The air motor part may include a flanged hollow ring spatially positioned below the cylinder and coupled to the cylinder base through multiple rod members. The distance between the cylinder base and the flanged hollow ring can be proportional to the length of the piston rod air motor part and the play of the piston rod. The piston rod extends from the center of the cylinder base and the rod members extend around the piston rod. The rod members are spaced apart from each other and from the piston rod. To the end of the piston rod is a piston rod coupler that allows connecting the piston rod to the pump part of the disclosed system. FIG. 5 shows an enlarged view of the piston rod coupler.

[0134] The pump part can include a flat disk, the dimensions of which correspond to that of the flanged hollow ring. The flanged hollow ring juxtaposes with the flat disk so that the pump part can be secured to the air motor part. A clamp can clamp the flanged hollow ring and the flat disk together. The use of a clamp as a fastener for coupling the flanged hollow ring and the flat disk allows for quick assembling and disassembling of the pump part from the air motor part.

[0135] In the center of the flat disk is an aperture through which a bolt rod passes through and extends upwards from the flat disk. The bolt rod can be hollow, and a second piston rod is slidable received within the hollow bolt rod. The proximal end of the second piston rod has a ball head. This ball head can be coupled with the piston rod coupler for operably clamping the pump part with the air motor part. For securing the pump part to the air motor part, the clamp can secure the flanged hollow ring and flat disk together. FIG. 3 shows the air motor part and the pump part separated. A clamp is also shown in FIG. 3. FIG. 2 shows the clamp is partially unclamped state while FIG. 1 shows the air motor part and pump part coupled together using the clamp.

[0136] The air motor part includes the cylinder; an implementation of the hollow cylinder is shown in FIG. 4. The cylinder cap is secured to the cylinder at the top, and the cylinder base is secured to the base of the cylinder. The cylinder cap and cylinder base can be secured using suitable fasteners, such as bolts. The directional control valve is a critical feature of the invention that can be connected to the cylinder cap and cylinder base through the manifold. FIG. 6 shows an exploded view of the whole assembly i.e., the air motor part and the pump part. It is understood that the manifold can be optional, and the directional control valve can be connected through any other means.

[0137] FIG. 7 is an exploded view of the air motor part showing the cylinder and the manifold. FIG. 10 shows another exploded view of the air motor part showing the cylinder and the piston rod. FIG. 11 shows an exploded view of coupling part of the assembly including the flanged hollow ring and the flat disk. The cylinder of the air motor receives a piston head of the piston rod, and the piston rod is coupled to the piston head. The other end of the piston rod has the piston coupler. The piston head is slidably received within the cylinder. The piston head can be moved up and down by air under pressure i.e., by pneumatic mechanism. A single source of pressurized air can be used to move the piston up and down in a reciprocating manner. A directional control valve can direct the air from the pressurized air source to an upper chamber and a lower chamber of the cylinder in an alternate manner. The cylinder cap and the top surface of the piston head can form the upper chamber while the cylinder base and lower surface of the piston head can form the lower chamber. The air under pressure can cause the lower chamber to expand, forcing the piston head to move upwards. Similarly, the air under pressure can cause the upper chamber to expand causing the piston head to move downwards.

[0138] The operation of the directional control valve can be mechanically controlled by an upper pilot valve and a lower pilot valve. The upper pilot valve can be disposed of in the upper chamber, preferably in the cylinder cap. The lower pilot valve can be disposed in the lower chamber, preferably in the cylinder base.

[0139] Each of the upper chamber and the lower chamber can be provided with an air intake duct from the directional control valve. The air under pressure from the pressurized air source can be directed by the directional control valve into the upper chamber through the upper air duct. Similarly, the air under pressure can be directed by the directional control valve into the lower chamber through the lower air duct. The upper air duct can be disposed in the cylinder cap while the lower air intake duct can be disposed into the cylinder base. It is understood, however, that the air intake ducts i.e., the upper air duct and the lower air duct can also be provided in the wall of the cylinder without departing from the scope of the present invention. The air intake ducts can open in the intake ports i.e., the upper intake duct opens in the upper air intake port and the lower air intake duct opens in the lower air intake port.

[0140] Each of the upper and lower chambers can also include an exhaust port through which air in the respective chamber can egress. An upper exhaust port can be provided in the cylinder cap while the lower exhaust port can be provided in the cylinder base. Through the exhaust ports, the air can only egress but not ingress into the respective chamber. The exhaust ports can be operably coupled to the respective pilot valves.

[0141] The directional control valve operated by the upper pilot valve and the lower pilot valve can switch between an up mode in which air is directed to the upper chamber and a down mode in which the air can be directed into the lower chamber. It is to be noted that the terminology upper chamber and lower chamber is for illustration only and is used to explain the working of the assembly. However, the volume of the upper chamber and lower chamber increases and decreases with the movement of the piston head.

[0142] The movement of the piston upwards is referred to herein as an upward stroke and downwards is referred to as a downward stroke. In the upward stroke, the air directional control valve is in the down mode and air under pressure fills the lower chamber causing the piston head to move upwards. The lower exhaust port of the lower chamber is closed and that of the upper chamber is open so that air from the upper chamber can egress. When the piston head reaches maximum stroke length, it triggers the upper pilot valve. The actuation of the upper pilot valve by the piston head causes the reversing of the directional control valve from the down mode to the up mode, the upper exhaust port closes, and the lower exhaust port opens. Now the air fills into the upper chamber resulting in the piston head moving downwards in the downward stroke, and the air in the lower chamber egressing from the lower exhaust port. The piston head moves downwards till it reaches the maximum stroke length and upon reaching the maximum stroke length, the piston head triggers the lower pilot valve. The lower pilot valve upon actuation causes the reversing of the directional control valve from the up mode to down mode, the upper exhaust port opens, the lower exhaust port closes, and the piston head moves upwards. The cycle is repeated to move the piston and thus the pump part of the assembly.

[0143] The above shows and describes the basic principles and main features of the utility model and its advantages of the utility model. Technical personnel in the industry should understand that the utility model is not limited by the above-mentioned embodiment. The above-mentioned embodiment and the description in the specification only illustrate the principle of the utility model. Without leaving the spirit and scope of the utility model, the utility model will have various changes and improvements, and these changes and improvements fall within the scope of the utility model that requires protection. The scope of patent protection required by the utility model is defined by the attached claims and its equivalent scope.

[0144] Referring to FIG. 12, illustrates the working of the directional control valve, the upper pilot valve, and the lower pilot valve. The directional control valve can include a reversing valve shaft that has an upper shaft head and a lower shaft head. The upper shaft head and the lower shaft head operate like pistons that can be driven by air under pressure. The direction control valve includes an air input port that is connected to a pressurized air source. The directional control valve includes an upper air supply path that connects to the upper chamber of the cylinder to fill the upper chamber with air from the pressurized air source. The directional control valve further includes a lower air supply path that connects to the lower chamber of the cylinder to fill the lower chamber with air from the pressurized air source. The reversing valve shaft can reciprocate to switch between the upper air supply path and the lower air supply path thus alternating filling the upper chamber and the lower chamber of the cylinder. The movement of the reversing valve shaft can be controlled by the upper pilot valve and the lower pilot valve. The housing of the directional control valve includes an upper cavity and a lower cavity, wherein the upper shaft head can move within the upper cavity and the lower shaft head can move within the lower cavity. The upper cavity and the lower cavity have an air input port such that air under pressure is filled into the cavities. Similar air paths connect the upper cavity to the upper pilot and the lower cavity to the lower pilot valve.

[0145] In operation, air enters the directional control valve from port A, it simultaneously enters the upper air cavity and the lower air cavity along the edge air path and enters the upper pilot valve and the lower pilot valve. The upper pilot valve is compressed by air, causing valve core to press gasket, making the upper pilot valve sealed. The lower pilot valve is compressed by air causing the valve core to press the gasket, making the lower pilot valve sealed. In a stationary state of the piston, the pressure in both the upper cavity and the lower cavity is balanced. The air source pushes the piston upwards i.e., in the upward stroke. When the piston hits the valve core of the upper pilot valve, the respective gasket seal opens, and the upper air intake port and the upper exhaust port of the upper pilot valve are connected. Since the lower pilot valve is in a sealed state and the upper air intake port is in the open state, the pressure in the upper cavity becomes significantly lower than the pressure in the lower cavity. This pressure difference that has greater pressure in the lower cavity causes the shaft to move upwards, thereby reversing the direction of the directional control valve. The air from the directional valve now is directed to the upper chamber and the piston moves downwards. When the piston reaches mid of its stroke length, the upper and lower pilot valves are sealed again at the same time. The pressure of upper cavity and the lower cavity in the directional valve is balanced.

[0146] FIG. 21 is a schematic diagram of the pilot valve controlling the directional valve. As shown in the figure, the air inlet is air intake, and the gas enters the upper F chamber and the lower G chamber respectively. The F chamber is sealed by the upper pilot valve, and the G chamber is sealed by the lower pilot valve; when the pilot valve is not touched, the pressure of the F chamber and the G chamber is the same, so that the piston of the directional valve remains stationary; when the cylinder piston moves upward (at this time, the gas enters the cylinder under the control of the directional valve piston), when it reaches the top and touches the upper pilot valve, the pilot valve squeezes the spring upward, and the sealing surface is opened at the same time, F The chamber communicates with the upper exhaust port, and the pressure becomes smaller; due to the continuous intake of air from the air inlet, the pressure in the G chamber remains unchanged for a short period of time, which forms a pressure difference with the smaller pressure in the F chamber, and the pressure pushes the piston of the directional valve to move upward; when the directional valve piston moves to the top, it controls the gas to enter the top of the cylinder piston, causing the cylinder piston to move downward; the cylinder piston leaves the pilot valve above, and at the same time, under the action of the spring, the sealing surface of the pilot valve above is sealed, and the pressure in the F chamber rises, which is consistent with the G chamber, so that the directional valve piston remains stationary; at this time the cylinder piston moves downward, When the cylinder piston reaches the bottom end and touches the pilot valve below, the pilot valve squeezes the spring downwards, and the sealing surface is opened at the same time, the G chamber communicates with the exhaust port below, and the pressure becomes smaller; due to the continuous intake of air from the air inlet, the pressure in the F chamber remains unchanged for a short period of time, which forms a pressure difference with the smaller pressure in the G chamber, and the pressure pushes the piston of the directional valve to move downwards; when the directional valve piston moves below, it controls the gas to enter the lower part of the cylinder piston, causing the cylinder piston to move upward; the cylinder piston leaves the pilot valve below, and at the same time, under the action of the spring, the sealing surface of the pilot valve below is sealed, The pressure in the G chamber rises and is consistent with the F chamber, so that the piston of the directional valve remains stationary; this completes the repeated reciprocating movement.

[0147] FIG. 22 shows the road map of the intake and exhaust of the cylinder. As shown in the figure, when the directional valve piston is above, the control gas enters from above the cylinder; when the directional valve piston is below, the control gas enters from below the cylinder.

[0148] FIG. 23 is a road map for the directional valve to control the exhaust. As shown in the figure, when the directional valve is below, the upper exhaust port is sealed and can only be discharged from below; similarly, when the directional valve is above, the lower exhaust port is sealed and can only be discharged from above.

[0149] FIG. 24 shows when air enters the Directional control valve from port A, it simultaneously enters the cavity aa (up) and cavity aa (down) along the edge air path, and also enters the upper pilot valve from the in (up) hole. From the in (down) hole, it enters the lower pilot valve. The upper pilot valve is compressed by air, causing valve core 3d (up) to press gasket 3e (up), making the upper pilot valve sealed. The lower pilot valve is compressed by air, causing valve core 3d (down) to press gasket 3e (up), making the lower pilot valve sealed. At this time, the pressure of cavity aa (up) and cavity aa (down) is balanced, with piston 1n (up) and piston 1n (down) in a stationary state and 1k in a stationary state, as shown in FIG. 12. The air source pushes piston 5b upward. When piston 5b hits the upper pilot valve core 3d (up) and moves upward, the Gasket 3e seal opens, and the inlet hole in (up) and outlet hole out (up) of the upper pilot valve are connected. The cavity aa (up) is also connected to out (up), and the lower pilot valve is in a sealed state at this time, The pressure in cavity aa (down) is greater than that in cavity aa (up), so the air pushes piston 1n (down) upwards, thereby pushing reversing valve shaft 1k upwards. The air direction of the directional control valve changes from pushing cylinder piston 5b upwards as shown in FIG. 12 to pushing piston 5b downwards.

[0150] The 5b piston completes the reverse rotation, and the upper and lower pilot valves are sealed again at the same time. The pressure of cavity aa (up) and cavity aa (down) is balanced, and the piston 1n (up) and piston 1n (down) are in a static state, while reversing valve shaft 1k is in a static state, as shown in FIG. 25. The 5b cylinder piston continues to run, hitting the lower pilot valve core to complete the upward direction change.