JPS6135748Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a switching device for switching the reciprocating motion of a diaphragm in a diaphragm pump.

[Technical background of the invention and its problems]

Generally, a diaphragm pump has a working fluid chamber and a pump chamber defined by diaphragms connected to each other by a center rod on both sides of the pump body, and a suction check valve is connected to the pump chambers on both sides. The suction port is connected to the pump via a discharge check valve, and the discharge port is connected to the discharge port via a discharge check valve, and a switching device alternately controls supply and discharge of working fluid to and from the working fluid chambers on both sides.

A switching device in a conventional diaphragm pump, as shown in Japanese Patent Application Laid-open No. 58-131384, for example, operates a reversing valve by the diaphragm on the side discharging the working fluid in the working fluid chamber, and operates the reversing valve by the diaphragm on the side discharging the working fluid in the working fluid chamber. The working fluid that drives the pilot valve (switching valve) is suddenly applied as switching pressure to one end of the spool of the pilot valve (switching valve), and the spool is suddenly switched.

When fluid pressure is suddenly applied to the end face of the spool in this way, the impact when the spool moves is large, and the impact noise causes noise.

[Purpose of invention]

The present invention improves the conventional switching of the switching valve spool by applying pressure to switching by reducing pressure in a switching device for a diaphragm pump, thereby reducing the impact when switching the spool and reducing the impact noise. With the goal.

[Summary of the idea]

The switching device in the diaphragm pump of the present invention partitions a working fluid chamber and a pump chamber through diaphragms interconnected by a center rod on both sides of the pump body, and a suction check valve is provided in the pump chambers on both sides. In the diaphragm pump, the suction port is connected through a discharge check valve, and the discharge port is connected through a discharge check valve, and the working fluid is alternately supplied and discharged to and from the working fluid chambers on both sides by a switching valve. Switching pressure reducing holes are made to face the working fluid chambers on both sides, and on-off valves are provided in the switching pressure reducing holes on both sides to open the switching pressure reducing holes in conjunction with the movement of the diaphragm just before the end of the working fluid discharge operation. A switching pressure chamber communicating with the switching pressure reducing holes on both sides faces the switching pressure chambers on both end surfaces of the spool of the valve, and the switching pressure chambers at both ends and the working fluid supply port to the switching valve are connected via an orifice. , the spool is switched by reducing the pressure in one of the switching pressure chambers at both ends of the spool by the opening operation of the on-off valve, and the working fluid is supplied to the working fluid chamber on the side where the working fluid discharge operation is completed.

[Example of idea]

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

As shown in the figure, the outer peripheries of diaphragms 5 and 6, which are sandwiched at the center by center disks 2 and 3 and interconnected by a center rod 4, are fixed to both sides of the pump body 1. , 6 to the inner working fluid chambers 7, 8
and outer pump chambers 9, 10.

A suction check valve 1 is installed in the pump chambers 9 and 10 on both sides.
The suction port 13 is connected through the valves 1 and 12, and the discharge port 16 is connected through the discharge check valves 14 and 15. Furthermore, in the working fluid chambers 7 and 8 on both sides,
Working flow holes 18 and 19 through which working fluid is alternately supplied and discharged by a switching valve 17 are exposed. The working fluid is air. The switching valve 17 is installed so as to be embedded in the center of the pump body 1, but in the drawing, for the sake of explanation,
It's outside.

In addition, the switching pressure reducing holes 21 and 22 are made to face the working fluid chambers 7 and 8 on both sides, and the switching pressure reducing holes 21 and 22 on both sides are made to face the switching pressure reducing holes 21 and 22 on both sides.
On-off valves 23 and 24 are provided at 1 and 22 to open the switching pressure reducing holes 21 and 22 in conjunction with the movement of the diaphragms 5 and 6 just before the end of the working fluid discharge operation.
The on-off valves 23 and 24 are connected to the pressure reducing holes 21 and 22.
A valve body 25 is screwed into the inside of the valve body 25, a push rod 26 is loosely fitted into the valve body 25, and an O-ring 27 as a valve body is attached to the rear small diameter portion of the push rod 26.
is fitted so that this O-ring 27 faces the valve seat 28, and a compression coil spring 29 is inserted between the rear end of the push rod 26 and the opposing surface of the pump body 1.
By attaching the push rod 26, the tip of the push rod 26 is made to protrude into the working fluid chambers 7 and 8.

The switching valve 17 has switching compression chambers 32 and 33 communicating with the switching pressure reducing holes 21 and 22 on both sides facing the switching pressure chambers 32 and 33 on both end faces of the spool 31, and a connection between the switching pressure chambers 32 and 33 at both ends and the switching valve 17. Working fluid supply port 34
are connected via orifices 35 and 36. Further, a detent mechanism 37 is provided at one end of the switching valve 17, and this detent mechanism 37 prevents the spool 31 from stopping at the neutral position and maintains the spool position when the pump vibrates when stopped. ing. This detent mechanism 3
7 is formed by providing a chevron-shaped convex portion 38 on the circumferential surface of the end shaft of the spool 31, and further having a ball 40 elastically pressed against the circumferential surface of the end shaft of the spool 31 by a compression coil spring 39, so that the spool 31 moves in the axial direction. When doing so, the convex portion 38 pushes the ball 40 into the spring mounting hole. There is no risk that the spool 31 will stop in a state where the chevron-shaped convex portion 38 and the ball 40 face each other in front (spool neutral position).

The switching valve 17 has ports 41 and 42 that are directly connected to the working fluid supply port 34, and ports 43 and 44 that are directly connected to the working fluid holes 18 and 19 of the pump body 1.
and a port 45 for discharging air as a working fluid to the atmosphere. Note that each of the ports described above is actually formed in a sleeve that fits into the spool 31, but the sribble is omitted in the drawings.

Next, the operation of this embodiment will be explained.

The switching valve 1 is opened at a predetermined pressure from the working fluid supply port 34.
Add air to 7.

At this time, the position of the spool 31 is such that the port 41 is open and the port 42 is closed, and air enters the port 43 through the port 41 and further enters the working fluid chamber 7 of the pump body 1.

At this time, the air in the working fluid chamber 8 on the opposite side flows through the hole 19.
The air is exhausted from the air through port 44 to the atmosphere through port 45.

Therefore, the diaphragms 5, 6 and the center rod 4 move to the left, and the diaphragm 5 pushes the fluid material in the left pump chamber 9 to the discharge port 16, and the diaphragm 6 pushes the fluid material from the suction port 13 to the right pump chamber 10. Suction fluid material inside.

Immediately before the end of this leftward movement, the end face of the center disk 3 pushes the push rod 4 of the on-off valve 24, and the air in the switching pressure chamber 33
It passes through the working fluid chamber 8, the hole 19, and the ports 44 and 45 in order and is exhausted to the atmosphere.

At this time, since the air discharge flow rate at the on-off valve 24 is larger than the air supply flow rate at the orifice 36, the balance between the pressures that were previously equal in the switching pressure chambers 32 and 33 at both ends of the spool 31 is lost, and the switching pressure Chamber 33 has a lower pressure.

Therefore, the spool 31 moves toward the switching pressure chamber 33, the port 41 is closed, the port 42 is opened, and the diaphragms 5, 6 and the center rod 4 are closed.
will move to the right.

Immediately before the end of this rightward movement, the automatic switching of the working fluid is performed in the same way, and the pumping action is repeated.

[Effect of idea]

According to the present invention, one of the on-off valves on both sides provided in the switching pressure reducing holes facing the working fluid chambers on both sides of the pump body opens in conjunction with the movement of the diaphragm just before the end of the working fluid discharge operation, so that the switching valve The spool is switched by depressurizing one of the switching pressure chambers pressurized by a part of the working fluid through an orifice at both ends of the spool, and the working fluid is supplied to the working fluid chamber on the side where the working fluid discharge operation is completed. Because of this, the switching pressure chamber of the present invention allows switching while receiving a gentle pressure supply from the orifice, rather than the conventional method where switching pressure is suddenly applied to one end of the spool to suddenly switch the spool. When the spools are switched by discharging the switching pressure into the fluid chamber, that is, by gradually reducing the switching pressure, the impact when switching the spools can be reduced, and the impact noise can be reduced. Furthermore, if the switching device of the present invention is used, the movement stroke length of the center rod can be reduced compared to conventional diaphragm pumps that directly take the movement of the center rod between the diaphragms on both sides and switch the supply and discharge of working fluid to and from the working fluid chambers on both sides. Regardless of the distance between the diaphragms on both sides, the distance between the diaphragms on both sides can be reduced, making the pump more compact.Also, only the switching valve requires precision machining, so there is no need for precision machining on the pump body. Therefore, it is advantageous in manufacturing.

[Brief explanation of the drawing]

The figure is a sectional view showing an embodiment of the switching device in the diaphragm pump of the present invention. 1... Pump body, 4... Center rod,
5, 6... Diaphragm, 7, 8... Working fluid chamber, 9, 10... Pump chamber, 11, 12... Suction check valve, 13... Suction port, 14, 15... Discharge check Valve, 16...Discharge port, 17...Switching valve, 2
1, 22... Switching pressure reducing hole, 23, 24... Opening/closing valve, 31... Spool, 32, 33... Switching pressure chamber, 34... Working fluid supply port, 35, 36... Orifice.

Claims (1)

[Scope of utility model registration request] A working fluid chamber and a pump chamber are defined on both sides of the pump body through diaphragms connected to each other by a center rod, and a suction port is connected to the pump chambers on both sides through a suction check valve, and a discharge chamber is connected to the pump chamber on both sides. In a diaphragm pump, the discharge port is connected through a check valve, and the working fluid is alternately supplied and discharged to and from the working fluid chambers on both sides using a switching valve, and the working fluid chambers on both sides have switching pressure reducing holes. The switching pressure reducing holes on both sides are provided with on-off valves that open the switching pressure reducing holes in conjunction with the movement of the diaphragm just before the end of the working fluid discharge operation, and the switching valves on both end faces of the spool of the switching valve are A switching pressure chamber communicating with the switching pressure reducing hole is faced, and the switching pressure chambers at both ends of the switching pressure chamber and the working fluid supply port to the switching valve are connected via an orifice, and one of the switching pressure chambers at both ends of the spool is connected. A switching device for a diaphragm pump, characterized in that the spool is switched by reducing the pressure by the opening operation of the on-off valve, and the working fluid is supplied to the working fluid chamber on the side where the working fluid discharge operation ends.