JPH10174803A - Removing method of gas in oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove dissolved air in an oil at a high eliminating ratio. SOLUTION: This device is constituted so that the oil 18 in the return side 17A of a storage tank 17 is delivered to a filter 13 side through a suction pump 10 with the suction pump 10 operated by the instruction of a driving controller 16 and after fed with a prescribed pressure and flow rate by a flow control valve 12 into a vapor-liquid separation membrane device 9. One or plural deaerating modules each provided with a box unit 2 of the vapor-liquid separation device 9, a separation membrane 3 and a shield 4 are provided and the oil is made to flow out a fixed quantity by increasing or decreasing the flow rate while keeping the discharge pressure applied to the deaerating module constant. The pressure of the space 5 in the box unit 2 is reduced to negative by evacuating from a discharge port 8 with a vacuum pump 15 operated by being synchronized with the operation of the suction pump 10 to remove the gas dissolved in the oil 18 and after that, the oil is returned to the discharge side 17B of the pump in the storage tank 17 from a flow-out port 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing gas dissolved in oil.

[0002]

2. Description of the Related Art At room temperature and atmospheric pressure, 5 to 10% by volume of air is dissolved in a liquid. Air dissolved in a liquid that is open to the atmosphere is a liquid under the pressure condition. Saturated amount is dissolved in it. When a fluid containing dissolved air flows and the pressure environment becomes lower than the initial atmospheric environment, the amount of saturated dissolved air decreases, and air that cannot be completely dissolved precipitates as bubbles in the liquid.

[0003] The oxygen in the dissolved air promotes the chain reaction of the oxidative deterioration reaction and shortens the life of the liquid. Also, since the compression rate of the bubbled air is about 10 ⁴ times the compression rate of the liquid, the bubble volume is compressed or expanded by a change in load, so that the hydraulic system has a delay in driving and a fluffy phenomenon. As a result, ups and downs are significantly generated, which hinders drive control.

In a conventional hydraulic device, in order to remove air bubbles, which are the lump of air that has precipitated, a partition wall or the like is provided in the tank to isolate the return side to the tank and the discharge side to the pump, and the buoyancy of the gas itself is provided. Is used to separate bubbles from liquid.

[0005] However, in the case of air-bubble separation which has been left unattended, it takes time to separate from the fluid. Therefore, it is necessary to increase the tank capacity so as to obtain the separation time, but this goes against space saving. Therefore, in recent years, in order to remove these bubbles, attention has been paid to the difference in mass between the liquid and the bubbles, and the liquid containing the bubbles is swirled and flowed in the liquid piping, and the swirling speed is added to the heavy liquid and the extremely light bubbles. A centrifugal force difference is generated along the tube wall depending on the speed and the mass, and thereby a swirling flow deaeration method for separating liquid and air bubbles is proposed, for example, Japanese Patent Application Laid-Open Nos. 1-104315 and 2-5-22013.
The invention is disclosed in JP-A-3-123605.

A cavitation deaeration method in which the required suction pressure or suction flow rate of the pump is reduced, and the pump is driven to a negative pressure to cause dissolved air to precipitate out of the liquid as bubbles when the liquid is sucked, thereby removing separated bubbles. Has been proposed.

Further, as a method for preventing tap water from flowing into a water supply pipe, the porous gas-liquid separation membrane is covered with a housing in the form of a hollow fiber, and the housing is evacuated to supply tap water through the hollow fiber. A method has been proposed in which the side is evacuated to separate dissolved gas in the liquid by passing tap water into the housing, and the invention is disclosed in, for example, JP-A-3-30889.

[0008]

However, in the conventional gas removing device using a swirling flow deaerator, the inflowing liquid uniformly contains minute gas that can be visually observed, and this liquid is placed outside the swirling flow. In addition, the bubbles are separated by flowing inside, but the reduction rate of dissolved air in removing bubbles by swirling degassing is less than 20%, preventing oxidation deterioration and suppressing compression and expansion against load fluctuation. However, it was not satisfactory with a hydraulic elevator or the like that requires a reduction rate of at least 90%.

Further, in order to lower the suction pressure of the pump in the cavitation degassing method, it is necessary to reduce the pressure by 50% from the atmospheric pressure.
It is desirable to reduce the pressure by mmHg or more, and by achieving this negative pressure value, a dissolved air reduction rate of about 50% can be obtained. This can be easily done by closing the tank and driving the pump with a negative pressure inside.However, if the inside of the tank is negative pressure, aeration that constantly separates gas from the working oil is generated, It cannot be provided in the system; a subsystem must be provided.

Further, in the case of a porous hollow fiber for tap water, there is a problem that the working oil having affinity has a problem that the working oil itself flows out from the pores of the separation membrane. No degasser is provided.

[0011] Non-porous membranes with very small intermolecular bonds with little leakage of hydraulic oil have been provided as gas separation membranes. The non-porous membrane and the hollow fiber of the porous membrane have a pressure resistance of 0.
When the inflow pressure is increased to increase the inflow rate into the hollow fiber, the membrane is damaged.

[0012] Also, in the resin of the shield part for obtaining the tightness between the bundled hollow fibers and the housing, the sealing property is alienated due to an increase in pressure due to insufficient strength of the hollow fibers themselves.

Therefore, in order to withstand long-term use, the inflow pressure into the housing and the hollow fiber must be kept low. Therefore, it took a long time to obtain a predetermined reduction rate of dissolved gas in oil.

It is an object of the present invention to provide a device for removing gas from oil, which can effectively remove dissolved air from oil at a high reduction rate.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a hydraulic device configured to pump oil in a storage tank to a hydraulic main circuit by a pump and return the oil from a return pipe into the storage tank. In order to remove the gas dissolved in the oil, in a gas removing device having a circulation circuit for circulating the oil in the storage tank through a gas-liquid separation membrane device, the separation membrane of the gas-liquid separation membrane device A hollow fiber shape of a non-porous membrane, the hollow fibers are bundled, and the both ends of the hollow fiber bundle are covered with a housing to form a gas-liquid separation membrane module in which a vacuum space can be obtained. It is characterized in that it is arranged in parallel with an oil feed pump that sends hydraulic oil to be degassed to the liquid separation membrane module.

As described above, the apparatus for removing gas in oil according to the present invention can secure an appropriate processing flow rate by increasing or decreasing the number of separation membrane modules in response to an increase or decrease in the amount of oil in the hydraulic device, and can effectively dissolve dissolved air in the oil. It can be efficiently removed at a high reduction rate.

[0017]

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

FIG. 1 is a block diagram of a device for removing gas in oil according to an embodiment of the present invention, and illustrates a jack device 25 of a hydraulic elevator as a hydraulic device.

A pump 20 having a motor 19 is connected to a cylinder 26 of the jack device 25 via a pipe 27 and a control valve 21 to form a hydraulic main circuit.

The inside of the storage tank 17 is divided into a return side 17A and a discharge side 17B to the pump by a partition plate 23, and the oil 18 in the storage tank 17 can be moved only through a lower communication portion of the partition plate 23. Has become.

The pump 20 is connected to the discharge side 17B of the pump 20 via a suction filter 22, and the control valve 21 is connected to the return side 17A via a return pipe 24. The pump 20 and the jack device 25 communicate with each other to perform the ascent operation of the hydraulic elevator, while the switching operation of the control valve 21 allows the return pipe 24 to communicate with the jack device 25 to perform the descending operation of the hydraulic elevator. ing.

The discharge side 17B of the storage tank 17 to the pump
The circulating path of the gas removing device 1 is configured separately from the hydraulic main circuit of the hydraulic device described above. The pipe 28 of the suction pump 10 of the gas removing device 1 is connected to the suction pump 10 via the check valve 11, and a pipe 29 is provided from the gas separation membrane device 9 to the storage tank 17B. A relief valve 11, between the suction pump 10 and the gas-liquid separation membrane device 9,
A flow control valve 12, a filter 13, and a pressure gauge 14 are connected.
Are connected by a pipe 8, and a vacuum pump 15 and a suction pump 1
0 is controlled by the drive control device 16.

The pressure gauge 14 is provided between the gas-liquid separation membrane device 9 and the flow control valve 12.

The return pipes of the relief valve 11 and the flow control valve 12 to the storage tank 17 both return to the return side 17A of the storage tank 17.

The gas-liquid separation membrane device 9 has an inlet 6 on the filter 13 side of the housing 2 and an outlet 7 on the discharge side 17B to the pump, and a non-porous hollow fiber in the middle. Gas-liquid separation membrane 3 is provided. The gas-liquid separation membrane 3 and the housing 2 are provided with a shield part 4, and the space 5 can be sealed. The hollow fiber gas-liquid separation membrane 3 covered with the housing 2 is called a degassing module.

The casing 2 of the degassing module is provided with a discharge port 8 for evacuating the space 5 and a vacuum pump 17 and the casing 2 are connected by a discharge pipe 8A.

Next, the operation of the apparatus 1 for removing gas in oil will be described.

When the suction pump 10 operates according to a command from the drive control device 25, the return side 17A of the storage tank 17
The oil 18 inside is sent to the filter 13 side via the pipe 29, the check valve 30 and the suction pump 10. The discharge pressure of the suction pump 10 is controlled to less than 0.5 MPa because the withstand pressure of the gas-liquid separation membrane 3 and the shield part 4 is within 0.5 MPa, and in order to secure a predetermined flow rate, the flow control valve 1
2 and the pressure gauge 14, but in order to obtain a predetermined flow rate at a low discharge pressure, the number of degassing modules in the gas-liquid separation membrane device 9 is arranged in parallel with one or two or more. , 1
By making the pressure applied to the module constant, it is possible to vary the total outflow amount without imposing a load on the separation membrane 3 and the shield portion 4.

Incidentally, in order to increase the flow rate when a plurality of deaeration modules are arranged in series, it is not suitable to arrange them in series because a pressure higher than that flowing into a single unit is applied to the deaeration modules.

As the filter 13, a filter having a diameter smaller than the liquid passage diameter of the gas-liquid separation membrane 3 is used. After removing contaminants in the oil 18 fed by the filter 13, the filter 13 is applied to the gas-liquid separation membrane device 9. The flow of the gas 18 prevents the oil 18 in the gas-liquid separation membrane 3 from being reduced by the contaminants.

A vacuum pump 15 operated in synchronization with the operation of the suction pump 10 according to a command from the drive control device 16
When the pressure of the space 5 in the housing 2 of the degassing module is set to approximately several torr, the oil 18 flowing into the gas-liquid separation membrane device 9 from the inlet 6 passes through the gas-liquid separation membrane 3 and is separated from the separation membrane. The gas dissolved in the oil is released to the outside of the film on the vacuum side, and the gas released to the space 5 is evacuated and removed from the outlet 8A.

Thereafter, the oil 18 from which the gas has been removed is supplied to the outlet 7.
From the storage tank 17 to the pump discharge side 17B.
According to the apparatus 1 for removing gas from oil in such a configuration, a gas removal rate of 90% or more can be obtained by an appropriate flow rate and the degree of vacuum in the housing 2, and the working oil 18 in the storage tank 17 can be dissolved in a short time. Air can be reduced.

When a plurality of degassing modules arranged in series are evacuated by a single vacuum pump 15, first,
First, the separation membrane 3 of the degassing module into which the oil 18 flows,
Gases matching the vacuum capacity of the vacuum pump 15 are removed. If a large amount of air is dissolved in oil 18, oil 1
Since the gas removed from 8 is extracted into the space 5, the degree of vacuum is reduced. Therefore, the degree of vacuum of the degassing module into which the oil 18 first flows in becomes the degree of vacuum of the gas-liquid separation membrane device 9 (not shown) provided with a plurality of degassing modules arranged in series. It is not possible to improve the degassing capacity of the individual degassing modules.

The gas-liquid separation membrane 3 can remove gas dissolved in the oil 18, but cannot remove mixed air bubbles, so that buoyant visible bubbles having a large particle diameter are naturally discharged. It is preferable that the oil 18 be separated from the oil 18 by air and the oil 18 containing dissolved gas be flown into the gas removing device 1. Therefore, the pipe 28 on the suction side of the hydraulic circuit is partitioned into the storage tank 17. It is preferable to provide it on the pump discharge side 17B side divided by the plate 23.

With this arrangement, the oil 18 containing bubbles generated when discharged from the return pipe 24 does not need to be sent to the gas-liquid separation membrane device 9. Further, it is preferable that the oil surface depth of the pipe 28 is set to a position close to the oil surface so that the oil 18 containing a large amount of re-dissolved gas can be treated.

Further, by supplying the oil 18 immediately after deaeration with a small amount of dissolved air to the pump 20 which feeds the oil to the hydraulic main circuit, the amount of the oil 18 which generates bubbles in the negative pressure environment when the pump 20 is sucked is reduced. Can be suppressed. Therefore, the pipe 29 for returning the oil 18, which has been reduced in the dissolved air deaerated by the gas-liquid separation membrane device 9, to the storage tank 17 is provided near the suction filter 22 on the pump 20 side for feeding the oil to the hydraulic main circuit, or Close to the tank bottom on the pump 20 side and return pipe 2
Positions further than 4 are preferred.

The gas removing device 1 is configured as a circulation circuit different from the hydraulic main circuit of the hydraulic device of the hydraulic elevator. Therefore, the dissolved gas in the oil 18 can be removed irrespective of the operation in the hydraulic main circuit of the hydraulic device of the hydraulic elevator, the timing of moving the oil, and the moving capacity of the oil.

As described above, since the operation of the gas removing device 1 can be controlled independently of the operation of the hydraulic main circuit of the hydraulic device of the hydraulic elevator, its performance, required gas removal rate or operating frequency of the hydraulic device of the hydraulic elevator can be controlled. The gas-liquid separation device is controlled so that the gas dissolution rate does not exceed a predetermined value so that the dissolution rate at which the gas dissolves in the oil 18 in the storage tank 17 is slower than the gas removal rate. Drive 1

For example, when the hydraulic elevator is operated and the oil 18 in the storage tank 17 moves up and down and the amount of dissolved gas is large, the gas removing device 1 is operated, and the hydraulic elevator stops operating at night. When the dissolution rate is extremely slow, the gas removing device 1 can be stopped. Further, the gas dissolving amount can be maintained at a predetermined value by performing an intermittent operation at a predetermined time interval.

Further, in order to suppress the dissolution of the gas, it is preferable to float a gas impervious film (not shown) on the liquid surface of the tank 17B on the oil feed pump 20 side of the storage tank 17.

At 17A on the return pipe 24 side, return pipe 2
Since the oil 18 containing air bubbles is returned to the storage tank 17 from 4, the air bubbles must be released, and the use of the gas impermeable membrane on the storage tank 17A side is not preferable.

[0042]

As described above, the apparatus for removing gas in oil according to the present invention is formed as a circulation circuit having a gas-liquid separation membrane device separately from the hydraulic main circuit of the hydraulic device. Operation can be performed regardless of the operation or oil transfer amount, and a predetermined processing flow rate can be secured without damaging the separation membrane and shield part, and gas dissolved in oil in the hydraulic main circuit of the hydraulic system can be effectively reduced at a high reduction rate. Can be removed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a device for removing gas from oil in one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas removal apparatus 2 Housing 3 Gas-liquid separation membrane 4 Shield part 5 Space 6 Inflow port 7 Outflow port 8 Outlet port 8A Discharge pipe 9 Gas-liquid separation membrane apparatus 10 Suction pump 11 Relief valve 12 Flow control valve 13 Filter 14 Pressure gauge 15 Vacuum pump 16 Drive control device 17 Storage tank 17A Return side of storage tank 17B Pump discharge side of storage tank 18 Oil 19 Motor 20 Pump 21 Control valve 22 Suction filter 23 Partition plate 24 Return pipe 25 Jack device 26 Cylinder 27 Pipe 28 Pipe 29 Piping 30 Check valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Tanakadate 1-6-6 Kandanishikicho, Chiyoda-ku, Tokyo Inside Hitachi Building System Co., Ltd.

Claims (4)

[Claims] 1. The storage tank for removing gas dissolved in the oil in a hydraulic device configured to pump oil in the storage tank to a hydraulic main circuit by a pump and return the oil from the return pipe into the storage tank. A gas-in-oil removing device comprising a circulation circuit for circulating the oil in the gas through a gas-liquid separation membrane device, wherein the separation membrane of the gas-liquid separation membrane device has a non-porous membrane hollow fiber shape, A bundle of fibers is used as a gas-liquid separation membrane module in which both ends of the hollow fiber bundle are covered with a housing to provide a vacuum space. When a plurality of modules are used, hydraulic oil to be degassed is sent to the gas-liquid separation membrane module. A device for removing gas from oil, which is arranged in parallel with an oil feed pump for oiling. 2. The hydraulic pump according to claim 1, wherein a position of a pipe for sucking oil to flow into the gas-liquid separation membrane module from the storage tank is a position close to an oil level near a pump suction side in the storage tank of the hydraulic main circuit. The apparatus for removing gas from oil according to claim 1. 3. The position of the return pipe for returning the oil flowing out of the gas-liquid separation membrane module to the storage tank is near the pump suction side in the storage tank of the hydraulic main circuit or near the tank bottom. The apparatus for removing gas from oil according to claim 1. 4. The method according to claim 1, wherein the return of the surplus oil to the storage tank after adjusting the flow rate of the oil discharged from the oil feed pump is performed on a return pipe side of the hydraulic main circuit into the storage tank. Gas removal device.