DE3504356A1 - Method and device for the lubrication of bearings of a rotary machine - Google Patents

Abstract

A refrigerating machine contains a compressor (1) and, in a closed circuit between the outlet and the inlet of the compressor, a condenser (24), a storage tank (25), an expansion valve (26) and an evaporator (27). The fluid in the circuit contains a small amount of dissolved oil. The liquid from the storage tank (24) is fed to a heated oil storage tank (132), which has outlets (151, 152, 153), which are connected to bearings of the compressor. In this oil storage tank the liquid is evaporated whilst oil is deposited. The gas resulting from this distillation process escapes through the outlets (151, 152, 153) to the bearings. Separate means (136 to 138, 140 to 145, 154 to 156) are provided for charging the gas escaping to the bearings with oil droplets. For this purpose each outlet duct leads under the oil level (146, 147) and is connected by way of a micro-aperture (154 to 156) to the oil. This method results in reliable lubrication of the bearings under relatively constant conditions. <IMAGE>

Description

PRINZ, LEISER, 3UN) KE & .PARTNER

Patent Attorneys European Patent Attorneys' "^ R Π Λ

Munich - Stuttgart

January 8, 1985

Bernard ROOMS

Vantage Point Condominium

6 New Street

East Norwalk, Ct 06855 / V.St.A.

Our reference: Z 486

Method and device for lubricating the bearings of a rotary machine

The invention relates to a method and a device for lubricating the bearings of a treatment machine a liquefiable gas, for example a refrigeration machine or an air treatment machine. Also relates the invention also applies to such a machine.

In FR-PS 1 331 998 and in FR-PS 1 586 832 there are single screw compressors described, which are used to compress cooling gases, for example halogenated hydrocarbons, can be used while condensate is injected into the compression chamber to cool the compressor. One Such a device is known from FR-PS 2,089, for example.

It is still necessary to ensure that the bearings are lubricated; this can be done in a conventional manner by taking oil from an oil pan by means of an auxiliary pump, is fed to the bearings and finally returned to the oil pan after the lubrication process. Such a device is for example in the document "The development of the single screw compressor and Oil Reduced Operation "by G.F. HUNDY et al, edited by "The Institute of Refrigeration", 1982, particularly in FIG. 7.

This method is expensive because it requires a pump; in addition, there may occasionally be oil leakage come into the cooling circuit, so it is necessary to constantly restore the oil level by, for example part of the liquid condensate is expelled by boiling with the aid of an additional heating device and the oil contained in the distillate in the mentioned oil pan is returned. This makes the device even more complicated.

In FR-OS 7 604 418 of February 10, 1976 the proposal was made to replace the bearings of rotating compressors, which are used in a closed circuit, for example a cooling circuit, in particular the Bearing of screw compressors, as described in FR-PS 1 331 998 and 1 586 832, with the help of a to lubricate oil mist.

The fundamentals of this solution are explained with reference to FIGS. 1 and 2.

FIG. 1 shows the circuit diagram of a typical cooling circuit as it is used for cooling purposes and for air conditioning is applied. A compressor 1 delivers

a condenser 24 pressurized gas, and the liquefied gas collects in a storage container 25, from where it via a line 104 to an expansion valve 26, an evaporator 27 and back again to the inlet of the compressor reaches via a line 107.

A portion of the condensed liquid is removed from the storage container 25 via an auxiliary line 20 and on Point 29 injected into the compressor so that it is cooled. Via one connected to the auxiliary line 20 Secondary line 10, some of the liquid reaches capillary tubes 11, 12 or 13, which are immersed in a housing 114 which contains a fluid, for example water, heated by means of a resistor 115. The liquid evaporated in the capillary tubes and the evaporation products illustrated by arrows 116, 117 and 118 are fed to the bearings that support various rotating parts of the compressor.

Fig. 2 shows an axial section through a typical arrangement of such a bearing.

The bearing sits inside the compressor housing 121 and is surrounded by the refrigerant gas. For example, one with the Screw or the gear wheel of a compressor according to one of the above-mentioned patent specifications integrally connected shaft 122 is rotatably supported by the bearing. The bearing is held in the housing by means of a nut 123, which has a central thread 124 surrounding the shaft 122 with a certain amount of play. For example, from the capillary tube 111 coming distillation products pass through the line 125 and the connection piece 126 at the rear of the bearing, lubricate the bearing, flow through the clearance between the shaft 122 and the nut 123 and reach the space 127, which is connected to the inlet of the compressor

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is in communication so that they are captured and recompressed.

The coolant generally contains 0.5 to 3% dissolved oil. During the evaporation in the capillary tubes appears this oil like a mist in suspension in the gas. It is centrifuged in the camps and used as a centrifugation lock acting central thread 124 partially retained. This central thread prevents this in the compressor circulating liquid refrigerants also prevent it from entering the bearing.

This known design is effective, but it has several Disadvantage.

First, it is undesirable to direct a lot of fluid into certain bearings that are lightly loaded. This leads to capillaries that have such a small diameter that they easily clog, which is a risk to the Storage involves and requires a filter device and as many safety devices as capillaries to be provided.

Second, it is not possible to check whether the gas fed into the bearings actually contains oil or whether there is oil in a zone of the circuit has been accumulated.

Third, the oil cannot be replaced if it is already has been used for a greater number of hours.

According to a first aspect of the invention, a method for lubricating the bearings is a compression or expansion machine used rotary machine in a closed circuit in which a fluid circulates, that from the liquid state to the vapor state and

the other way around, the bearings are supplied with a mixture of oil and the fluid in a gaseous state is, which is then fed back into the closed circuit, characterized in that in a lower area of a reservoir oil is attached that the reservoir from the closed circuit is charged with fluid that in the reservoir contained in the fluid oil at least is partially separated from the fluid and in that the mixture is prepared by removing gas from a upper area of the storage container is mixed with oil from the lower area of the storage container.

Instead of supplying a mixture with a medium proportion of oil to the bearings, there is the one according to the invention Process in which oil is separated from the mixture and a new mixture is produced from the oil and the gas, in which the Proportion of each of the two components can be adjusted at least approximately easily. The new mix can can be heavily enriched with oil without the need for the fluid in the closed circuit as well to be heavily enriched with oil.

The storage container can be fed via a common line, so that only one line is present in which can lead to constipation; in addition, this line is wider and less prone to clogging.

Oil that has already been used for a long period of time can be used in the reservoir, which contains the majority of the total amount in use.

According to a further aspect of the invention is an apparatus for lubricating the bearings of a rotary machine according to the above method, with feed lines for supplying fluid from the closed circuit to several lubrication lines that have an end that is in

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at least one of the bearings ends, characterized by a reservoir that holds oil to a certain level may contain and which is inserted between the feed lines and the plurality of lubrication lines, wherein the Lubrication lines on the one hand with the reservoir above the oil level and on the other hand below the oil level above at least communicate with a micro-opening.

According to a preferred embodiment, the micro-opening is below the oil level in the storage container.

This design has several advantages:

- It ensures an exact distribution of the oil on the various bearings; this distribution is made possible by the The diameter of the micro-opening and its depth below the oil level are determined; to ensure the desired Distribution, it is sufficient to change one or the other of these parameters or both parameters;

- It ensures controlled cooling of the warehouse; this cooling is done much more by the gas than caused by the oil, and the gas flow can be controlled by a suitable selection of the line cross-section be precisely controlled;

- When the oil level in the storage tank decreases, it also increases the flow through the micro-opening automatically decreases, while in the opposite case it increases, which leads to self-stabilization of the level guaranteed.

It also has an advantage that is useful when lubricating in a refrigerant compressor is important. As is known, a refrigerant compressor can use liquid refrigerant

top up when stopped, with the result that all of the oil is removed from the bearings, leaving them Bearings can be completely dry when operations resume.

According to the embodiment of the invention described above, oil trickles through the micro-opening when the machine is stopped is, the oil fills the entire cross-section of the pipe below the oil level. When starting the presses In the storage tank, the pressure prevailing the oil in the bearing, which immediately with a lot of fresh oil is supplied by correctly dimensioning the volume of the lubrication line attached below the oil level can be adjusted.

Instead of the at least one micro-opening, a very large number of micro-openings can be provided by building part of the partition between each lubrication line and the interior of the reservoir porous material, such as sintered metal, can be created. This enables easy adjustment of the passage cross-section offered to the oil, in which the area of the material is set, and it is possible to create a wide passage zone that is less prone to clogging by contaminants than one Micro-opening is.

According to a third aspect of the invention is a machine, for example a refrigeration machine or heat pump including one -Compressor with a closed circuit between an outlet and an inlet of the compressor, which may contain a circulating fluid that changes from a liquid state to a gaseous state State and vice versa can pass, the compressor rotatable parts and the rotatable parts in a housing contains bearing bearings, characterized in that one

Contains lubricating device according to the above.

In one embodiment of the machine, which on semi-hermetically sealed compressors, for example by an electric motor driven compressor, in which a refrigerant gas circulates, can be used, is the liquefiable, Oil-containing gas into the storage container leading line connected to a liquid line and surrounds the stator of the motor, while another part of the stator with the housing enclosing the stator is combined that passages arise in which the gas received by the compressor circulates.

Due to the large amount of heat made available by the engine, this embodiment ensures that excess gas is introduced into the reservoir and that the return of the oil is accelerated, while most of the engine cooling can be done by conventional means.

Another embodiment of the invention is characterized in that that a point in the reservoir above the oil level with a point in the housing of the compression machine is connected, which is subjected to a pressure between the inlet and outlet pressure, and that the line for feeding the storage container connected to the closed circuit at one point away from it which is subjected to a higher pressure than the intermediate pressure.

Embodiments of the invention will now be explained in more detail with reference to the drawing. Show in it:

Fig. 3 shows a further embodiment of a cooling

medium circuit with a compressor using a device according to the Invention,

FIG. 4 shows a section of the device from FIG. 3,

Fig. 5 is a perspective exploded view

development of a detail of Fig. 4,

Fig. 6 shows another embodiment of the inven

proper device,

7, 8 and 9 different embodiments of the

Sections of the middle plate of Fig. 5,

10 shows a further embodiment in comparison

to the embodiment of Fig. 5,

11 shows a partial section of an electric motor

a semi-hermetically sealed refrigerant compressor according to the invention,

12 shows a partial section along the line XII-XII

of Fig. 11,

13 is a schematic perspective view showing the

obtained by various grooves in the housing of the motor of Figs Management and

14 is a circuit diagram of a closed circuit

run in which the device is used with an expansion machine.

The embodiment shown in Figs. 3 to 5 is explained only in relation to their differences from the embodiment of FIG.

A reservoir 130 that holds oil 132 up to a level 33 contains, is provided with several lubrication lines 151, 152, 153, which take the place of the capillary tubes 116, 117, 118 of Figure 1; these lubrication lines are connected to individual Warehouse attached.

Fig. 4 shows a more detailed section of the storage container.

The storage container 130 is connected via a capillary tube 131 a line such as the line 20 of FIG. 1 is connected, in which, for example, the refrigerant coming from the condenser is present under pressure. In the storage container there is a supply of oil 132, which by means of a thermostatic Resistor 133 is heated. The side wall of the storage container has a zone penetrated by holes 135, to which three plates 136, 137 and 138 are tightened by means of bolts 139; these plates can be seen in the exploded view of FIG.

The intermediate plate 137 is provided with U-shaped cutouts 140, 141, 142, which when firmly held together between the Plates 136 and 138 form U-shaped tubes. One of the top The ends of each U-tube meet with a wide opening in the plate 136, for example the opening 143, 144 or 145 together, which in turn are connected to the interior of the storage container via perforations 135. It is to see that they are above the oil level indicated by the dashed lines 146, 147. The top end the other leg of each Ü-tube meets with holes, for example holes 148, 149, 150 in the plate together, at which the ends 151, 152, 153 of lines

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are attached, the other ends of which lead to the various bearings to be lubricated. There are three lines shown, however, the device can also be used for two or more lines depending on the number of lines to be lubricated Bearings are used, it can be seen that it is sometimes possible to have several bearings in a row on the same line to lubricate.

It can also be seen that the plate 136 is equipped with micro-holes 154, 155, 156, each opposite the lowest section of each U-tube and below the oil level lie. The device works as follows:

Liquid arrives via the capillary tube 131, which then falls into the oil 132, is heated by the resistor 133 and evaporates. Part of the oil that is contained in solution was is accumulated while the vaporized gas through the openings 143, 144, 145, the U-tubes and finally flows through the lubrication lines 151, 152, 153 to the bearings.

During its passage through the U-tube, the gas is charged with the oil dripping through each of the micro-openings.

If the oil level should decrease, there will be a reduction in the Flow proportionally larger for the microholes furthest above. At the lower positions Therefore, those micro-openings should be made that feed the most heavily loaded bearings.

The bearings are mainly cooled by the gaseous flow, although by providing different Cross-sections for the openings, for example the openings 143, 144, 145 generated different amounts of flow can be.

When the compressor is stopped, there is no longer any circulation through the lines and U-tubes. That Due to its own weight, oil continues to trickle into the U-tubes, and the level in each tube is approaching to the level in the storage tank. When the compressor starts again, the first one wears penetrating into each pipe Gas kick the oil into the bearings with it, which is extremely desirable if the compressor is on during the Stop phase has been filled with liquid refrigerant and the bearings have been washed dry.

In the example given above, the movement of the gas generated by a pressure difference between the condensed liquid and the suction pressure. Most of this Difference is usually lost in the capillary tube and the pressure drop between reservoir 130 and the compressor inlet is only a few tenths of a bar.

Without modifying the invention, the generation of these Pressure difference and the production of the mixture of oil and gas can be carried out in a different way. For example is It can be seen in FIG. 6 that the storage container 130 is attached in the suction circuit between the line 7 and the compressor 1 can be. A throttle point 160 is shown between the reservoir and the compressor, which has a slight Pressure drop generated. The gas arriving in the storage container, which after evaporation, for example in an evaporator, Carrying oil droplets separates from some of its oil. The pressure drop caused by the restriction 160 ensures the pressure difference necessary to bring about gas circulation through the U-tubes. It should be noted that the liquefiable gas in this case is in the gaseous state and not as in the previously described example in liquid enters the reservoir.

In a preferred embodiment of the invention, the plate 136 is made of a porous material, for example made of sintered metal; the single micro-opening is created in this way by a large number of micro-openings replaced. This has the advantage of simpler production compared to machine production the micro-openings where it is difficult to get an exact diameter; in this solution will also reduce the risk of clogging from contaminants avoided because it has a very large filter surface. Another advantage is that a better adjustment of the flow to the oil level is made possible. When the oil level drops, there may be an interest insist that the flow is disproportionately high in certain camps and underproportional in certain other camps to reduce.

In FIGS. 7, 8 and 9, various cutouts are shown which are used to produce the U-tubes in the plate 137 can be attached; the left side of each figure shows the downward leg of the tube.

If χ is the height of the oil level above the baseline of the pipe in the case of FIG. 7, the oil flow is approximately

3/2
proportional to χ ', in the case of FIG. 9 approximately proportional

5/2
χ 'and in the case of Fig. 8, ie when the flow is through

1/2 a single micro-opening occurs, roughly proportional to χ '. The sensitivity for the height of the oil level is therefore im Case of FIG. 9 and even in the case of FIG. 7 considerably higher than in the case of FIG. 8.

It is not necessary to use U-shaped tubes. In Fig. 10, an embodiment is shown in which only a single vertical leg is used for each tube; the outputs 151a, 152a, 153a are in the lower part Section. The plate 13 6a consists of a porous material,

for example made of sintered bronze, and its edge 161 is tin-plated, so that leakage at the edge is prevented.

This solution gives the same results as the solution shown in Fig. 5 with the exception of the accumulation of oil during a business interruption. If so desired, all that is necessary is to achieve the same result the pipes emanating from the outlets 151a, 152a or 153a are passed through a point above the level as indicated by dashed lines on tube 153a, or there must be a shut-off valve in each of these tubes be attached, which is closed in the event of a break in operation of the compressor, as on the pipe 152a with dashed lines Lines is indicated.

To separate the oil from the gas, it is necessary to evaporate the coolant. This is achieved by either the oil is removed from the already evaporated refrigerant entering the compressor, as shown in FIG. 6 or that the liquid is detected and heated to evaporate, as shown in FIG.

Without changing the invention, a mixture of gas and liquid could for example also on the delivery side of the Compressor generated and completely evaporated by heating.

In the same way, the distillation of the liquid could not be done by just using a resistor according to Fig. 4, but can also be achieved by using other heat sources, for example by the discharge released heat by the compressed gas that the Compressor escapes, is fed into pipes that are immersed in the oil of the storage container.

In a preferred embodiment, in the case of a hermetic or semi-hermetic compressor, the heat should be used of the electric motor can be used for this distillation.

Such an embodiment is shown in FIGS.

11 shows a section of a semi-hermetic electric motor, in which the invention is applied. With "hermetic electric motor" an electric motor is referred to, the runs inside a housing that is hermetically connected to the rest of the coolant circuit, with the interior of the housing is filled with the cooling gas circulating in this circuit. They are the ones driving the compressor, not shown Motor shaft, the rotor 63, the stator 64, and the housing surrounding the stator shown. The case, which is made up of three Elements 66, 67 and 68 is assembled with the aid of bolts 69 and 70.

The element 66 has a plurality of longitudinal projections 71, 72 (FIG. 12) which hold the stator and between which axial grooves 73, 74 are provided, in which the sucked in by the compressor and through the opening 75 of FIG. 11 in the direction of the Arrow 76 penetrating gas flows. The gas flowing through the engine cools it in a known manner.

In each elevation there is a groove 77 which reverses inward to form a U.

The various grooves in this elevation are connected to one another with the aid of grooves in element 67, which are shown in FIG. at 80 and in Fig. 12 are shown in phantom. Each groove 80 runs along only part of a circle, so that two axial grooves 77, which are mounted in two successive longitudinal elevations, are connected to one another.

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One of the grooves 77 is on an opening and on a feed line 81 is connected, and in the same way an outlet port and an outlet pipe are provided as they are shown schematically at 82 in FIG.

The feed line 81 is connected to the line 20 of FIG. 3, and the outlet conduit 82 is in communication with the reservoir 130.

This device makes it possible to bring liquid into contact with the stator and the stator by evaporation of the To cool liquid, while the conventional system of cooling the engine by passing the aspirated Gas is retained.

The advantage of using the engine heat to evaporate the liquid is that a large amount of it Heat is available, which allows the evaporation of an excess of liquid, so that the return line of the Oil in the reservoir is accelerated and the amount of unused oil remaining in the circuit is reduced will.

An improved alternative is to use an auxiliary line a point of the reservoir 130, which is above the oil level, with a point in the compressor housing connect, which is subjected to a pressure lying between the suction pressure and the discharge pressure. This causes a considerable Reduce the work of recompression of the vaporized gas to separate the oil and it becomes vaporization allows larger amounts of liquid without impairing the efficiency. This embodiment yields also a stabilization of the pressure in the reservoir and thus contributes to the stability of the flow rate through the lubrication lines.

The device can be used whether the oil is now complete is partially soluble in the refrigerant (for example R 22) or, in the case of ammonia, not soluble. Im last In this case, it is not necessary to carry out a careful distillation, since the oil is at the high pressure can be recovered directly, however some heating of the oil is still preferable to allow absorption a major part of the gas is eliminated by the oil.

The device remains effective even when more than a single gas flows in the circuit.

The device is not only suitable for ball bearings as described above, but also for other types of bearings, e.g. roller bearings, journal bearings, etc.

The device is for the case of application to a Compressor has been described, but it can also be used in an expansion machine without modification, such as it is used, for example, in a closed circuit to generate energy; the vaporizer is lying down then on the high pressure side, while the condenser is on the low pressure side. The liquid to be distilled is then on the high pressure side between the pump, which is used to raise the pressure from the condenser level to the Evaporator level is required and detected by the evaporator.

Such a circle is shown in Fig. 14, where an expansion machine 90 between an evaporator 91 on the high pressure side and a condenser 92 on the low pressure side lies. The condensed liquid in the condenser 92 falls into a receptacle 93 and is over a line 94 is detected by a pump 95 which pushes it into the evaporator where it is evaporated. Part of the liquid can be injected into the expansion machine via line 96 to cool and lubricate it.

- V5 -

A secondary line 131b enables the transfer of a
small portion of the liquid in a storage container 130b, which is similar to the storage container 130 of FIG. 4 and contains a device according to the invention, from where the lines 151b, 152b, 153b to the to be lubricated
Storage of the expansion machine 90 run out.

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Claims (1)

PRINCE, QUIET, BUNKE [ge! PARTfME-R Patent Attorneys European Paterii Attorneys' ο C Π / O C Munich Stuttgart J 0 U 4 J 0 b February 8, 1985 Bernard ROOMS Van-tage Point Condominium 6 New Street East Norwalk, Ct 06855 / V.St.A. Our reference: Z 486 Claims 1. Procedure for lubricating the bearings of a compression or expansion machine used rotary machine (1) in a closed circuit (24, 25, 104, 26, 27, 107), in which a fluid circulates that changes from the liquid state to the vapor state and vice versa can pass, the bearings (120) being a mixture of oil and is supplied to the fluid in a gaseous state, which is then fed back into the closed circuit is, characterized in that oil (132) is attached in a lower region of a storage container (130) is that the storage container (130) from the closed Circuit is charged with fluid that contained in the reservoir in the fluid oil is at least partially separated from the fluid and in that the mixture is prepared by that gas from an upper region of the reservoir is mixed with oil from the lower region of the reservoir will. ORIGINAL INSPECTED \ 2. The method according to claim 1, characterized in that that the reservoir (130) is heated for the purpose of separating the oil from the fluid. 3. Device for lubricating the bearings of a rotary machine according to the method of claim 1 or 2, with Feed lines (131) for supplying fluid from the closed circuit (24, 25, 104, 26, 27, 107) several lubrication lines (151, 152, 153; 151a, 152a, 153a; 151b, 152b, 153b) which have an end (126) which ends in at least one of the bearings (120), characterized by a reservoir (130) that holds oil (132) to a certain extent May contain level (33) and inserted between the feed lines (131) and the plurality of lubrication lines is, the lubrication lines on the one hand with the reservoir (130) above the oil level (33) and on the other hand communicate below the oil level (33) via at least one micro-opening (154, 155, 156). 4. Apparatus according to claim 3, characterized in that the storage container (130) can be heated. 5. Apparatus according to claim 3, characterized in that the micro-opening (154, 155, 156) is below during operation the oil level (33) is. 6. Apparatus according to claim 5, characterized in that each lubrication line (151, 152, 153) near the reservoir (130) is U-shaped and that the micro-opening (154, 155, 156) is made in a lower region of the U-shape. 7. Apparatus according to claim 5, characterized in that each lubrication line (151a, 152a, 153a) is adjacent to the storage container (130) is directed upwards towards the other end from a position opposite the micro-opening Has section. 8. Apparatus according to claim 7, characterized in that the lubrication line (152a) is provided with a shut-off valve is. 9. The device according to claim 3, characterized in that each lubrication line (151a, 152a, 153a) with the aid of a Wall (136a) of porous material, which forms the at least one micro-opening, from the interior of the reservoir (130) below the oil level (33) is separated. 10. Machine, for example a refrigeration machine or heat pump, including a compression machine (1) or an expansion machine (90), with a closed circuit (24, 25, 104, 26, 27, 107; 92, 93, 94, 95, 91) between an outlet and an inlet of the compression or expansion machine in which a circulating fluid may be contained that can change from a liquid state to a gaseous state and vice versa, wherein the compression or expansion machine rotatable parts (122) and the rotatable parts in a housing (121) bearing bearing (120), characterized in that the machine includes a device according to any one of the claims 3 to 9 for lubricating the bearings of the compression or expansion machine. 11. Machine according to claim 10, characterized in that the lines for feeding the storage container from grooves (77, 78, 80) exist, which are formed between a housing (66) and a stator (64) of an electrical machine which is in a driving connection with the compression or expansion machine. 12. Machine according to claim 11, characterized in that an interior of the housing of the electrical machine is connected in series with the closed circuit adjacent to the compression or expansion machine and that the grooves (77, 78, 80) from the interior of the housing are separated. 13. Machine according to one of claims 10 to 12, characterized in that a point in the storage container above the oil level with a point in the housing of the compression machine is connected, which is subjected to a pressure between the inlet and outlet pressure, and that the line for feeding the storage container connected to the closed circuit at one point away from it which is subjected to a higher pressure than the intermediate pressure.