Fluid-degassing System

Abstract

The system removes gases and moisture from dielectric fluids such as, for example, insulating oils normally used to provide electrical insulation between electrical components in a tank filled with such dielectric fluid. Degassing occurs in a treatment reservoir into which the fluid is initially introduced and such degassing is accomplished using a combination of vacuum and ultrasonic vibration and also, in some instances, the fluid may be heated in the reservoir to a sufficiently high temperature to assure efficient liberation of moisture from the fluids. Special valving and connections between the treatment reservoir, the aforementioned tank and a supply container provides versatility and transfer of fluids under optimum conditions. For example, the fluid may be first introduced into the treatment reservoir from a supply container and then after treatment in the reservoir be transferred to the tank wherein the same serves as an insulating medium for electronic equipment; alternatively the fluid already in the tank may be treated by causing the same to enter the treatment reservoir for treatment after which the fluid is returned to such tank.

Description

The present invention relates to the improved means and techniques for degassing dielectric fluids.

Briefly, dielectric fluids initially supplied in a supply container 42 may be transferred to a tank 40 in which they are ultimately used as an insulating medium after being treated in a treatment reservoir 10 under vacuum and ultrasonic vibration. Special valving and conduits interconnected with a vacuum pump 62 provide optimum fluid transfer under ideal conditions such as, for example, the fluid is not contaminated by atmosphere during its transfer from the treatment reservoir 10 to the tank 40 in which it is ultimately used.

The term "degassing" has reference also to the removal of moisture under those conditions wherein, for example, the fluid is heated to condition the moisture for removal by vacuum.

An object of the present invention is to provide improved means and techniques whereby dielectric fluids are degassed and transferred under optimum conditions.

A specific object of the present invention is to provide a system of this character in which a tank for dielectric fluids may be filled with such fluids either from an original supply container or by the dielectric fluid which was once in the tank and which required degassing.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

The single FIGURE of the drawing illustrates in schematic form the hydraulic and electrical equipment embodied in the present system.

The dielectric fluid is treated in a reservoir 10 referred to herein as a fluid treatment chamber, to which a vacuum may be applied via line 12 simultaneously with the application of ultrasonic vibrations produced by three ultrasonic transducers 14, 16, and 18 acoustically coupled to the bottom tank wall 20.

The tank 10 may be of rectangular construction with windows 21 and 22 in opposite end walls of the same such that the light from a long light bulb 24 may pass, in turn, through the window 21, through the fluid F in tank 10, through the opposite window 22 and glass sight gauge 26. The general purpose of this optical arrangement is to allow a person to observe the fluid level in tank 10 and also to observe the gas bubbles being formed at or near the bottom of the tank 10 and rising upwardly for removal by vacuum applied to the vacuum line 12.

The transducers 14, 16 and 18 are supplied with ultrasonic current from the source 30 which is effective when the on-off switch 32 is closed to apply the energizing voltage 34 to source 30. The energizing source 34 has been shown as a DC source but, of course, this showing is diagrammatic and the source may be an AC or a DC rectified source.

The tank 10 is connectable in a special manner to a fluid tank 40 or to a supply container 42 through corresponding fittings or conduit-connecting means 44, 46 and 47. Actually, in practice, the apparatus located between the fittings 44, 46 on the one hand and 47 on the other hand, is mounted as a separate unit so as to be mobile and be connectable to the tank 40 and/or supply container 42. For purposes of the present description, it will be assumed that the tank 40 has its inlet and outlet 40A, 40B respectively connected to fittings 44 and 46 herein referred to as conduit-connecting means and that the supply container 42 has its outlet 42A connected to the fitting 47. The tank 40 is representative of any container or housing of electronic equipment in which there is also present a dielectric fluid within which the electronic equipment is immersed for insulation purposes. The fluid in container 42 may either be new fluid as originally supplied by a manufacturer or fluid reconditioned as described herein.

Fitting 47 is connected to the inlet 10A referred to herein as a fluid port, of tank 10 via valve 50 and a filter 52 such that fluid may enter the tank 10 through the fill line 54, valve 50, line 56, line 58, filter 52 and line 60. During such filling operation the tank 10 may be evacuated using an electrically driven vacuum pump or vacuum-producing means, 62 which has its suction line 64 extending from vacuum port 62A, connectable to the tank opening 10B referred to herein as a vacuum port, via line 66, valve 68 and line 70. The pump 62 may have its pressure line 72 extending from discharge port 62B vented to the vent line 76 via check valve 78, line 80 and the two-position, three-way valve 82 which is illustrated in its vent position. As illustrated, line 80 terminates at a stationary port 80A and vent line 76 terminates at a stationary point 76A and the two ports 76A and 80A are communicated by the L-shaped channel 84A in the movable or rotatable valve member 84. The valve member 84 is rotatable from its position shown in the drawings to a position 180.degree. with respect to the same where the port 80A may then be placed in communication with a stationary port 88A leading to a line 88 whose function is later described.

The previously mentioned vacuum pump 62 may be operated by closing the on-off switch 90 to thereby apply current from the energizing source 92 to the electrically driven pump 62.

Using the arrangement previously described, it will be seen that the reservoir 10 may be filled with fluid from container 42 by (1) connecting the supply container 42 to the reservoir fill line 54, (2) operating the valve 82 to its vent position shown in the drawings, (3) opening valves 50 and 68, (4) operating the vacuum pump 62 by closing switch 90. During this filling operation the readings on the vacuum gauges 93 and 95 may be observed and checked to reassure that, for example, a vacuum pressure of 21 inches of mercury pressure exists in lines 66 and 70, the gauge 93 being connected to line 66 and the gauge 95 being connected to line 70. Also during this filling operation the liquid level in the tank may be continuously observed through the glass sight gauge 26 and when the fluid level reaches a desired amount, which may, for example, be somewhat less than 5 gallons valves 50 and 68 are then closed and the vacuum pump 62 may be deenergized by opening switch 90. Thus in this condition the treatment reservoir 10 is filled and in condition for degassing.

The fluid degassing process involves the following steps, namely:

1. energization of the sonic energy generator 30 by closing switch 32,

2. operating the vacuum pump 62 by closing switch 90,

3. opening valve 68, the valve 82 being still in its vent position illustrated in the drawings,

4. the vacuum and sonic energy is thus supplied for a duration of approximately 30 minutes after which,

5. the valve 68 is closed and the switches 90 and 32 are then opened in that order.

The next operation involves the transferring of the treated fluid from the reservoir 10 to the module or tank 40. This involves apparatus in addition to that previously described and in general valves 100, 102, 104, gauge 106 and overflow tube 108, and a vent line or air line 110 which is in communication with the atmosphere through an air filter 112. One side of valve 100 is connected to tank opening 10C via line 111 and the other side of valve 100 is connected to the vent line 110. Valve 102 has one side thereof connected to vacuum line 66 and the other side of valve 102 is connected to line 114. A fixed orifice or restrictor 120 is interposed between vent line 110 and line 114. The pressure in line 114 may be monitored by the vacuum gauge 106 which is connected to line 114. Valve 104 has one side thereof connected to line 114 and the other side connected to the overflow tube 108 via line 124. The other end of overflow tube 108 is connected to fitting 46.

Thus with the equipment described above flow is transferred from the treatment reservoir 10 to the module or tank 40 in accordance with the following procedure:

1. The fluid inlet tank opening 40A is connected to the fitting 44 and the tank outlet 40B is connected to the other fitting 46,

2. the valve 100 is slowly opened until the reading on vacuum gauge 95 begins to drop in which case air enters solely through the filter 112, the valve 100 being opened slowly to prevent breaking of surface tension of the fluid in reservoir 10 and when the gauge 95 reads substantially zero the valve 100 is fully opened, and then

3. valves 102 and 104 are opened to thereby communicate the vacuum line 66 with the upper end of tank 40, valve 100 still remaining open, and then

4. switch 90 is close to operate the vacuum pump 62, then

5. the readings on gauges 95 and 106 are compared in which case the reading on gauge 95 may be in the range of 0 to 1 inch of mercury pressure whereas the reading on gauge 106 may be in the order of 8 inch of mercury pressure, this difference in pressure being caused by the pressure drop across the fixed orifice 120, and this pressure drop is an indication that fluid is being drawn through the tank opening 10D and check valve 130 and fitting 44 to the fluid tank inlet 40A, and

6. the overflow tube 108 which is of clear glass is observed and when such tube 108 begins to fill the module or tank 40 is completely full and thus the overflow tube condition serves as an indication that the valves 102, 100 and 104 should be quickly closed in that order followed by a deenergization of the vacuum pump by opening switch 90.

It will be noted from the foregoing operation in which fluid is transferred to the module 40 that fluid enters the tube 108 and the next step described below involves the evacuation of the vacuum line and overflow tube 108 which is essentially a transparent conduit. This is accomplished in the following sequence, namely:

1. the flexible fluid line 140 and flexible vacuum line 142 are disconnected from the tank 40 and the flexible vacuum line 142 is extended into a waste container, and then

2. valves 68 and 100 are opened, and then

3. valve 82 is operated to its other position to the so-called "pressure" position wherein ports 80A and 88A are interconnected by the L-shaped channel 84A thereby placing the line 124 in communication with the vacuum pump pressure line 72 via check valve 78, and then

4. the vacuum pump switch 90 is closed in which case this causes air to flow through filter 112, valve 100 and through opening 10C to the top side of the reservoir 10, i.e. the vacuum side of the pump, through line 72 and through the check valve 78 and through line 82 to force all residual fluid out of the overflow tube 108 and into the waste container, and then

5. after all fluid has thus been blown out of the overflow tube 108 and vacuum hose 142, the valve 82 is moved to its "vent" position illustrated in the drawings, and then the vacuum pump switch 90 is opened and then valves 68 and 100 are closed.

The apparatus described also allows transfer of fluid from the module or tank 40 to the degassing unit or reservoir 10 and this is accomplished in the following sequence, namely:

1. The vacuum lines 142 and inlet line 140 are connected to the tank 40 and then

2. valves 68, 104 and valve 200 are opened, the valve 200 having one of its sides connected to the fluid line fitting 44 and the other one of its sides connected to the previously mentioned line 56 and 58. At this stage it will be observed that the opening of valve 68 places the top side of reservoir 10 in communication with the vacuum line 66, but the opening of valve 104 allows the topside of the module or tank 40 to be vented to the atmosphere through the orifice 120 and vent line 110 and filter 112, and that the opening of valve 200 places the tank inlet 40A in communication with the inlet side of the filter 52 through which fluid may then flow into the bottom of tank 10 through opening 10A, and then

3. the vacuum pump switch 90 is closed, and then

4. the differential reading between gauges 106 and 95 is observed in which case the gauge 106 may read 7 inches to 8 inches of mercury pressure, whereas the gauge 95 may read 20 inches to 21 inches of mercury pressure, and then

5. the interior of reservoir 10 is observed for the appearance of large bubbles which do appear when the module 40 is completely empty. Of course, the capacity of the reservoir 10 is greater than the capacity of the tank 40, and then

6. valves 68, 104 and 200 are closed in that order after which the vacuum pump switch 90 is opened.

It is noted that in the foregoing description of the five operations it was assumed, as is the case, that all valves are originally closed and that all valves, with the exception of valve 82, are on-off valves and that valve 82 as previously described either communicates line 80 to the atmosphere or to line 88. Further, valve 82 is operated only during the operation in which fluid is removed from overflow tube 108, and even in that case valve 82 is initially in the vent position and after that operation is restored to its vent position.

Thus, it will be seen from the foregoing that fluid introduced from supply container 42 may be treated in reservoir 10 and then discharged into the module or tank 40. Alternatively, fluid in the module or tank 40 may be introduced into the reservoir 10 where it is treated and then returned to the tank 40. In each case the fluid is transferred under vacuum conditions and without opportunity for the oil to be contaminated by ambient atmosphere.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

Claims

I claim:

1. Apparatus for treatment of fluids including a fluid treatment chamber, said chamber having a vacuum port located near the top of said chamber; said chamber having a fluid port located near the bottom of said chamber; an air line; first conduit-connecting means; means for communicating said air line with said first conduit-connecting means; second conduit-connecting means; means for communicating said fluid port with said second conduit-connecting means; said first conduit-connecting means and said second conduit-connecting means being connectable to a fluid tank; vacuum-producing means; means communicating said vacuum-producing means with said vacuum port; first valve means in said means communicating said vacuum-producing means with said vacuum port; second valve means connected between said air line and said vacuum-producing means and operable to intercommunicate said air line with said vacuum-producing means; third valve means in said means for communicating said fluid port with said second conduit connecting means; additional means for communicating the bottom of said chamber with said second conduit-connecting means; check valve means in said additional means for preventing fluid flow from said second conduit-connecting means to the bottom of said chamber but allowing fluid flow from the bottom of said chamber to said second conduit-connecting means; and means associated with said chamber for degassing fluids contained therein, an enlarged transparent conduit in said means communicating said air line with said first conduit-connecting means for serving as an overflow; said transparent conduit having one of its ends connected to said first conduit-connecting means and the other one of its ends connected to said air line; said vacuum-producing means including a vacuum pump having a vacuum port and a discharge port, said pump vacuum port being connectable with said chamber vacuum port; valve means connected between said pump discharge pump and said transparent conduit for communicating said pump discharge port either to the atmosphere or to that side of the transparent conduit which is connected to said air line; and additional valve means for intercommunicating the top of said chamber with said airline.

2. Apparatus as set forth in claim 1 including a third conduit-connecting means for connection to a supply container, additional valve means the last mentioned valve means having one of its sides connected to said third conduit-connecting means and the other of its sides in communication with said means communicating said second conduit-connecting means with the bottom of said chamber.

3. Apparatus for treatment of fluids including: a fluid treatment chamber; first conduit-connecting means; second conduit-connecting means; said first and second conduit-connecting means being connectable respectively to the top and bottom of a fluid tank; third conduit-connecting means for connection to a fluid supply container; valve means for communicating said third conduit connecting means with the bottom of said chamber; an air line; means communicating said air line with said first conduit-connecting means, means communicating the bottom of said chamber with said second conduit-connecting means; vacuum-producing means; valve means for communicating said vacuum-producing means with the top of said chamber; valve means for intercommunicating said vacuum-producing means with said first conduit-connecting means; and valve means for communicating the top of said chamber with said air line; and valve means in said means communicating said air line with said first conduit-connecting means, an enlarged transparent conduit in said means communicating said air line with said first conduit-connecting means; said vacuum-producing means comprising a pump having a vacuum port and a discharge port; valve means connected between said vacuum port and the top of said chamber for communicating said vacuum port with said top of said chamber; valve means connected between said vacuum port and said air line for communicating said port with said air line; said transparent conduit having a first end thereof connected to said first conduit-connecting means; and valve means connected between said discharge port and said transparent conduit for connecting said discharge port to either the atmosphere or to the other side of said transparent conduit.

4. Apparatus as set forth in claim 3 in which said means communicating said second conduit-connecting means with the port of said chamber includes a check valve for preventing flow in a direction from the second conduit-connecting means to said chamber; and additional valve means for communicating said second conduit-connecting means with the bottom of said chamber.

5. Apparatus as set forth in claim 2 in which said fluid treatment chamber includes a pair of spaced transparent sidewalls and a bottom and a top; a light source adjacent one of said walls; liquid level indicating means on the other of said walls; and means coupled to said bottom for transmitting ultrasonic vibrations to the fluid in said chamber for the formation of gas bubbles.

6. Apparatus as set forth in claim 2 including fluid filter means through which fluid flows into said chamber either when fluid is transferred from said tank or from said supply container.