DD205219A1 - HYDRAULIC MECHANICAL PROTECTION DEVICE FOR PUMPS - Google Patents

Abstract

The invention relates in particular to oil-immersed rotary vane vacuum pumps with a valve located in the suction chamber, which shuts off the active pump part from the recipient or container at standstill of the pump. The aim is to ensure an oil-free, secure sealing of the evacuated apparatus from the active pump part when the pump is at a standstill. The object is to develop an oil-free, vacuum-tight closing protective valve, which is operated without separately driven pressure medium source when the pump is stopped. The object is achieved by providing a centrifugal mechanism in the area of the drive coupling, the flyweights of which move a sealed control piston in the drive shaft axially against a helical spring provided in the hollow shaft neck of the clutch, the control piston having a check valve and a ventilation valve, which is a protective device actuated, communicates.

Description

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Title of the invention:

Hydraulic-mechanical protective device for pumps

Field of application of the invention:

The invention relates to a hydraulic-mechanical protective device for pumps, in particular for oil superimposed rotary vane vacuum pumps, with a located in the suction or in the suction line between active pump part and recipient valve which shuts off the active pump part of the recipient or container at standstill of the rotary vane vacuum pump, wherein the negative pressure is lifted on the suction side of the pump.

Characteristic of the known technical solutions: oil-sealed vacuum pumps, in particular all known under the collective term "oil rotary vacuum pumps" designs, have the property that in case of sudden standstill, caused by power failure, defective V-belts, etc., the connected equipment or the recipient is ventilated via the pump and at the same time oil enters the recipient, which spoils the batch in most cases, and the result is a complicated cleaning of the recipient, associated with production loss, which leads to increased costs and taxed the final product.

To solve this problem, various approaches have been taken. Most well-known are the separate, so-called pre-pump protection valves attached to the suction nozzle. These work with an electromagnetic, powered by the motor circuit auxiliary valve, which opens in case of power failure ^, so that the penetrating atmospheric air closes the valve abruptly and thus separates the recipient of the pump and vented it.

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For smaller pumps up to approx. 80 m / h pumping speed, these protective devices have been integrated into the pump. For space-saving reasons, these pumps are usually coupled to the drive motor; At the same time new ways of valve actuation are taken. It is known a solution in which, when the pump is stopped, the pressure cylinder of the protective valve for closing the suction opening of the pump in the closed position and with the atmosphere via an open electromagnetic auxiliary valve is in communication. The pressure cylinder is evacuated during commissioning of the pump via a correspondingly mounted ventilation bore between the pressure cylinder and suction channel within the pump, and the valve plate connected to the pressure piston gfbt by spring force the suction to the recipient free. The solenoid of the auxiliary valve is fed by a directly pushed onto the pump shaft generator. If the rotation of the rotor shaft stops - due to power failure, clutch failure, etc. - and the generator no longer generates voltage, then the solenoid of the auxiliary valve can not remain energized and thus the auxiliary valve is opened by the atmospheric pressure and in part supported by spring force; Air flows into the pressure cylinder and presses the pressure piston with its valve disk on the seat and closes the protection valve with simultaneous ventilation of the suction pump room to prevent rising of the working oil to the suction nozzle of the pump or recipient and beyond the pump chamber - working space - the pump not overly to fill with oil, which has a serious startup result DE-OS '24 51 685.

From DD-PS 151 487 a shut-off valve is known which is actuated by a directly coupled to the rotor shaft pressure medium source without auxiliary valve so that after the vacuum pump housing and suction flange, the pump is vacuum-tightly separated from the recipient and immediately thereafter a sudden ventilation of the suction pump chamber , This is achieved in that a valve stem, which is movably arranged in a sealing element which separates the vacuum from the atmosphere side, has a ventilation hole which is pushed over this sealing element during the closing process, which causes the ventilation of the suction-side pump chamber.

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A vacuum valve arranged on the vacuum side and limited axially displaceable valve plate and corresponding arrangements of the ventilation hole cause the ventilation takes place only after the vacuum-tight separation The first solution has the disadvantage that in addition a generator is needed to the auxiliary valve for the operation of other closing members driving. The second embodiment has the disadvantage that the existing rubber or 'other elastic material sealing element is overrun twice by the control bore at each actuation, which leads to TJndichtheiten in no time, and on the other hand, a separate printing unit is required.

Aim of the invention!

The aim of the invention is to ensure a safe oil-free sealing of the evacuated apparatus or the recipient of the active pump part in case of sudden standstill of the pump, constructively integrate the complete protection device in the pump while reducing costs and susceptibility.

Explanation of the essence of the invention:

The invention has for its object to develop an oil-free, vacuum-tight closing protection valve, for example, for oil-sealed rotary vacuum pumps, which is operated without separately driven pressure medium source when the pump is stopped. The separation between the suction nozzle on the pump or the recipient and the pump chamber on the suction side has to take place abruptly. Shortly after shutting off the pump room, it must be connected to the atmosphere. During commissioning, the connection of the pump chamber and the atmosphere on the suction side must be closed and, once the vacuum has been reached, the barrier must be removed both in the pump room and in the recipient and a connection between the recipient and the pump must be established directly.

According to the invention the object is achieved in that in the area provided for the drive of the rotary valve piston clutch, a centrifugal mechanism is arranged, the Fliehgewi switch a located in the drive shaft sealed control piston axially against a provided in Hohlwellenh _a ls of the clutch coil spring, wherein the control piston via a blocking oil passage and supply lines with both a check valve and with a vent valve, which operates a protective device in communication.

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The invention is further distinguished by the fact that the valve disk of the protective device is designed as a hollow piston and can be moved axially against a helical spring. In a further embodiment of the invention, the check valve between the supply line and the pump chamber is arranged.

Embodiment:

In the following the invention will be explained in more detail by an embodiment with reference to the drawing:

A in the drive chamber 1 and at the clutch 2 in the drive shaft 3 of the rotary valve piston 4 reaching centrifugal mechanism 5 moves due to friction frictionally arranged in the hollow shaft 6 sealing piston with rotating pump 8, due to the centrifugal weights 9, against a prestressed cylindrical coil spring 10th In a relaxed cylindrical coil spring 10, realized by an intentional or unintentional shutdown of the pump 8, according to the invention via the barrier oil passage 11 and the supply line 12 by moving the conical piston 7 generates a pressure while the vent valve 14 is opened, which on the other hand, the mechanism of the protection device 15th through the incoming atmosphere

21 moves and this the valve plate 16 on the valve seat 17 in the "closed" position presses and thereby aerated the pump 8 and produces pressure equalization with the atmosphere 21, so that the pump 8 is separated from the Eezipienten or recipient-side pump chamber 18.

When commissioning the centrifugal mechanism 5, due to the rotation of the drive shaft 3 and flyweights 9, set in motion, so that the control piston 7 generates a suction in the barrier oil passage 11 and feed line 12. As a result of this effect, the vent valve 14 closes, and the pump 8 generates a negative pressure in the suction-side pump chamber 24 and at the same time above the valve disk 16 of the protective device 15; As a result, the valve disk 16 is no longer pressed by the atmospheric pressure 21 onto the valve seat 17 and by the spring

22 moves to the "open" position, and it starts the normal pump delivery.

Must be filled due to leakage in the sealing oil channel 11, oil 13, so sucked at the suction stroke 23 of the control piston 7 via the arranged check valve 19 from the pump chamber 20 oil or this already realized by the negative pressure of the pump 8.

Claims (3)

234106 2 - claim of invention: 1. Hydraulic-mechanical protection device for pumps, especially for oil superimposed rotary vane vacuum pumps, located in the suction or in the suction line between active pump part and recipient valve that shuts off the active pump part of the recipient or container at standstill of the rotary vane vacuum pump, the negative pressure on the Suction side of the pump is canceled, characterized in that in the region of the drive for the rotary valve piston (4) provided for coupling (2) a centrifugal mechanism (5) is arranged, whose! "Liehgewichte (9) located in the drive shaft (3) sealed Control piston (7) axially against a in the hollow shaft neck (6) of the clutch (2) provided coil spring (10) move, wherein the control piston (7) via a blocking oil passage (11) and supply lines (12) both with a check valve (19) and with a vent valve (14), which operates a protective device (15) is in communication. 2. Hydraulic-mechanical protection device according to item 1, characterized in that the valve disc (16) of the protective device (15) formed as a hollow piston and axially against a coil spring (22) is movable. 3. Hydraulic-mechanical protection device according to item 1 and 2, characterized in that the check valve between the supply line (12) and the pump chamber (20) is arranged. - See 1 page drawing -