JPS6026190A - Pressure balance valve for piston vacuum pump - Google Patents

Abstract

PURPOSE:To simplify the structure considerably by opening/closing a pressure balance valve for feeding pressure into a cylinder by means of piston itself. CONSTITUTION:Only the foot rod 18 of a pressure balance valve 16 for closing the valve port 15 through resilience is projected to a cylinder 2 without projecting a pressure balance sleeve 10 fixed to the delivery chamber 9 side. A press chip 20 for pushing the foot rod 18 to open said valve 15 near the final stage of compression stroke is provided on the piston head. Consequently, only the pressure balance valve 16 is provided movably to function it directly by means of the press chip 20 of piston 3. Since a mechanism for driving said valve 16 is not required independently, the structure can be simplified considerably. Also since the sleeve 10 is not movable, occurrence of faults can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure balancing valve for a piston vacuum pump.

A rotary vacuum pump such as a vane type does not have reciprocating motion like a piston type vacuum pump, so it does not have a suction valve or a discharge valve, and has a pump mechanism that compresses the diluted gas that is vacuum-suctioned and releases it to the discharge side. Comparative curved section structure 1) Like the piston type, sealing oil is supplied from the suction side to enhance the vacuum suction function and 1) prevent seizure.
Install an oil mistake 1 recovery device or oil spill prevention valve on the discharge side,
It is necessary to prevent oil leakage 1 from being mixed into the compressed exhaust gas on the discharge side. However, there is nothing that can completely prevent oil mist from entering the compressed IJF air, and not only is oil-contaminated exhaust emitted into the atmosphere from exhaust chimneys, etc., but the amount of sealing oil consumed is extremely large. In addition, many high vacuum models require more than 50% of the piston reciprocation driving power of a piston type vacuum pump.

On the other hand, piston-type vacuum pumps require less driving power for the piston, and can effectively reduce the rate of sealing oil mixed into the compressed exhaust gas and the consumption of oil sealing oil. If the diluted gas sucked into the vacuum pump is not compressed to a pressure that overcomes the pressure on the exhaust side during the same compression stroke (usually the external pressure, and in the case of the first stage pump of a two-stage vacuum pump, it is less than the external pressure), the discharge valve will close. Since it cannot be opened, it is necessary to install a pressure balance valve that introduces the discharge side pressure into the cylinder at the end of the compression stroke.The balance valve is connected to an eccentric cam by, for example, a crank mechanism that drives the piston rod. and a valve for introducing the discharge side pressure into the cylinder by driving a slide valve by the mechanism of the eccentric cam.
1! C. It is configured to interlock a slide valve that opens and closes when necessary, and the ignition pressure balancing valve that is connected to the slide valve and the crank mechanism that is the drive mechanism for this valve are large-scale and
However, there are disadvantages such as low power consumption, and the use of relatively low-horsepower screw-type vacuum pumps is limited.

The present invention aims to improve the above-mentioned drawbacks by making the above-described pressure balance valve open and close by the reciprocating piston itself, and has one end facing inside the front wall of the cylinder. The pressure balancing sleeve is fixed to the discharge side, and a pressure balancing valve is movably provided inside the pressure balancing sleeve to close the valve opening provided in the balancing sleeve by J force from the discharge side. A leg rod protruding from the balance valve is loosely inserted into the valve port and protrudes into the cylinder, and the head of the screw I collides with the leg rod during the compression stroke and is pressed in a direction that resists the biasing force. It is characterized by the provision of a pressing piece.

Embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a two-stage piston-type vacuum pump, in which the first stage pump (I) and the first stage pump (It) are pumped into a cylinder 2.22 attached to the end plate 1, which alternates between suction stroke and compression stroke. Screws 1 and 24 for reciprocating stroke are fitted and connected to piston rods 4 and 24, respectively, which are driven by the side of the crank R.

The end plate 1 has a suction valve 6 and a discharge valve 7 corresponding to the first stage pump (I) and a suction valve 2 corresponding to the second stage pump (II').
6 and a discharge valve 27, the cover 5 is attached to the end plate l,
A suction v8 connected to a suction pipe 8a, a discharge chamber 9 connected to a discharge pipe 9a, a suction chamber 28 connected to a suction vibrator 28a, and a discharge chamber 29 connected to a discharge pipe 29a are connected to each suction valve 6.26. , are provided correspondingly to the discharge valves 7 and 27, respectively. The suction pipe 8a is connected to a vacuum chamber etc., the discharge pipe 9a is connected to the suction vibe 28a, and the discharge pipe 2
9a is connected to an exhaust pipe or the like.

This embodiment has the above-mentioned known structure ζ, and a first sleeve 1o for pressure balancing and a second sleeve 30 for pressure balancing, each having one end facing into the end plate 1 which is the front end wall of the cylinder, are connected to the discharge chamber 9 and the discharge chamber 9. They are each protruded and fixed into the chamber 29 separately. The first sleeve 10 for pressure balancing and the second sleeve 30 for pressure balancing have mounting collars 1i fixed to the outside of the end plate 1.
31 respectively, and step portions 12a, 32a are formed from the respective protruding ends of the discharge chamber 9 and the discharge chamber 29.
Insert 32, and then press pressure hole 13.33 and ventilation hole 1.
4.34 and a valve port 15.35 on the cylinder 2.22 side are formed respectively.

16.36 is a pressure equalization valve inserted into the pressure equalization YSL sleeve 10 and the second sleeve respectively from the discharge chamber 9.29 side; a rod 17.37 inserted into the C1 guide sleeve 12 or 32; Leg rods 18.38 protruding into the ζ cylinder 2.22 passing through the center of each column 15.35 are provided respectively, and a first spring 19 and a second spring 39 with a JJI angle are attached to the stepped portions 12a and 32a. As a force - ζbenguchi 15.35
press against.

A pressing piece 20.40 is provided at the center of the head of the piston 3.33, which abuts against the leg rod 18.38 during the compression stroke.

The first sleeve lO for pressure balancing and the suppressing piece 20 and the second sleeve 30 for pressure balancing and the suppressing piece 40 are provided with a groove a not shown in FIG. Make sure not to block the valve port 15.35.

The operation of the above embodiment will be explained.

When the piston 3 is sucked by the first stage pump (+) through a stroke in the direction of the arrow X in FIG. The mouth 15 is also a valve rod 17 which is biased by the first spring 19.
The valve is closed, and thin waste such as the vacuum chamber is sucked into the cylinder 2.

When the piston 3 moves to the compression stroke as indicated by the arrow y in Figure 2,
The diluted gas in the cylinder 2 is compressed, and the suction valve 6 is closed by the pressure, but the discharge valve 7 is not opened because the compression pressure of the gas is low. As the piston 3 further advances in the direction of the arrow y, near the end of the movement, the pressing piece 20 of the head pushes the leg rod 18 and pushes the pressure equalization valve 16 as shown in the figure against the bias of the first spring 19. Therefore, the valve port 15 is opened and the pressure in the discharge chamber 9 flows into the cylinder 2. Therefore, the pressure inside the cylinder 2 increases and is compressed, and the discharge valve 7 is opened to discharge compressed gas into the discharge chamber 9.The piston 3 moves from the compression fulcrum again to the first
When moving to the suction stroke shown in the figure, the pressure piece 20 is separated from the leg rod 18 until the valve port 15 is opened, and the pressure in the cylinder 2 is higher than the pressure in the suction chamber 8, so the suction valve 6 is closed. Although the valve may not open, the pressure piece 2 ( ) separates from the leg rod 18 and the internal volume of the cylinder 2 is expanded by the suction stroke of the piston 3 back and forth, so the pressure decreases and the suction valve 6 is closed. Open the valve and suck in the diluted gas.

The action of the reciprocating stroke of the screw 23 of the second stage pump (I[) is the same as that of the piston 3.

As clarified from the above description, the present invention is based on the cylinder of a piston type vacuum pump.The cylinder of a piston type vacuum pump has a pressure parallel sleeve which protrudes from the discharge chamber side which is blocked off via the discharge valve and is fixed to the cylinder without protruding into the cylinder. , is inserted into one front end wall and communicated through the opening of the ``ζ valve port, and only the foot rod of the pressure equalization valve that opens and closes the ``ζ'' valve [1] by the biasing elasticity protrudes into the cylinder, and the piston is connected to the piston for the compression stroke. Push the leg lever near the end (the head is equipped with a pressure piece that opens the valve port, and the power valve that introduces pressure into the cylinder is movably installed, and the valve can be opened or closed). Since the valve is operated directly by the pressure piece of the piston,
There is no need to provide a separate mechanism to drive the pressure balancing valve, and since the pressure balancing sleeve is immovable, there are fewer parts that can fail, and it is easy to replenish pressure when compression pressure is insufficient during the compression stroke. It has the effect that can be achieved with a simple configuration.

[Brief explanation of drawings]

The attached drawings show an embodiment of the present invention, FIG. 1 is a vertical side view, and FIG. 2 is a diagram showing the piston in a state of opposite movement to that in FIG. A perspective view of a sleeve and a pressure balancing valve i, and FIG. 4.5 is a perspective view showing several examples of a pressure balancing sleeve and a pressing piece. 30-・Second pressure balancing sleeve 2 → cylinder 3 → screw 1 6-◆Suction cuff→Discharge valve 9-Discharge chamber 12-Guiding sleeve 13-Pressure through hole
1'5-child mouth

Claims (1)

[Claims] In a piston-type vacuum pump, the suction valve is opened during the suction stroke of the piston to create a vacuum suction into the cylinder, and during the same compression stroke, the discharge valve is opened to discharge the compressed gas in the cylinder. The pressure balancing sleeve facing inside the front end wall of the cylinder is fixed to the discharge side, and the pressure balancing by closing the Jf mouth provided on the balancing sleeve by the A:J force from the discharge side. A valve is removably provided inside the pressure balancing sleeve, a leg rod protruding from the pressure balancing valve projects into the sill, and the head of the piston is provided with a valve that collides with the leg rod during the compression stroke. A pressure balance valve for a piston type vacuum pump, characterized in that a pressure piece is provided that opens the pressure balance valve by pressing the pressure balance valve in a direction that resists the force.