CN103649653A

CN103649653A - Refrigeration circuit with oil compensation

Info

Publication number: CN103649653A
Application number: CN201180072300.5A
Authority: CN
Inventors: S.黑尔曼; C.克伦
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2011-07-14
Filing date: 2011-07-14
Publication date: 2014-03-19
Anticipated expiration: 2031-07-14
Also published as: EP2732222B1; WO2013007310A1; CN103649653B; EP2732222A1

Abstract

A refrigeration circuit (2) comprises a circulating refrigerant and in the direction of the flow of the refrigerant: at least one compressor (4a, 4b, 4c) of a first type; a heat rejecting heat exchanger (6); an expansion device (8); and an evaporator (10). The refrigeration circuit (2) further comprises at least one compressor (12) of a second type; an oil collector (26), which is selectively connectable to the compressors (4a, 4b, 4c) of the first type and/or to the compressors (12) of the second type for providing a fluid connection between the oil collector (26) and the respective compressors. The oil collector (26) is selectively connectable to a high-pressure line (36) for increasing the pressure within the oil collector (26) in order to transfer oil from the oil collector (26) to the least one compressor (12) of the second type.

Description

There is the refrigerating circuit that oil subsidy is repaid

Technical field

On the flow direction of circulating refrigerant, refrigerating circuit comprises at least one compressor, heat rejection heat exchanger, bloating plant and evaporimeter, and this refrigerating circuit is known in the statement of this area.It is also known that, additional economizer is set with further cooling to leaving the cold-producing medium of heat rejection heat exchanger before being inflated at cold-producing medium, thereby improves the efficiency of refrigerating circuit.

Background technology

This economizer comprises the compressor that at least one is additional, and this additional compressor is with the suction pressure operation higher than the compressor of refrigerating circuit.

Due to higher suction pressure, the oil (it is for lubricate compressors) that the compressor of economizer is lost to (circulating in refrigerating circuit) cold-producing medium is more than the compressor of refrigerating circuit.Along with the passage of running time, this effect causes gathering oil in the compressor of refrigerating circuit, and causes the oil in the compressor of economizer to run off.Oil level in the compressor of economizer drops to lowest order when following, and compressor may seriously be damaged.

Therefore, there is the demand of the compressor of economizer that oil is got back to from the compressor transmission of refrigerating circuit.

Summary of the invention

Therefore, will be advantageously, a kind of refrigerating circuit and a kind of method of moving this refrigerating circuit are provided, this refrigerating circuit and method allow compensation oil between the compressor that sucks level run with difference, and allow especially oil to be passed to second group of compressor with the work of higher suction (entrance) pressure from first group of compressor with the work of low suction (entrance) pressure.

Exemplary embodiment of the present invention comprises a kind of refrigerating circuit, and it makes refrigerant circulation and on the flow direction of described cold-producing medium, comprises at least one compressor, heat rejection heat exchanger, bloating plant and the evaporimeter of the first compressor bank.Described refrigerating circuit also comprises at least one compressor and the oil interceptor of the second compressor bank, described oil interceptor is optionally connected in the described compressor of described the first compressor bank and collects excessive oil with described at least one compressor from described the first compressor bank, and/or is connected in the described compressor of described the second compressor bank.Described oil interceptor is optionally connected in high-tension line to increase the pressure in described oil interceptor, thereby oil is delivered to described at least one compressor of described the second compressor bank from described oil interceptor.

The other exemplary embodiment of the present invention comprises a kind of method of at least one compressor of the second compressor bank that oil is delivered to from least one compressor of the first compressor bank by oil interceptor, described oil interceptor is optionally connected in described compressor, and described method comprises step: the oil groove that described oil interceptor fluid is connected in to the described compressor of described the first compressor bank; Pressure in described oil interceptor is reduced to below the suction pressure of described compressor of described the first compressor bank, to oil is drawn into described oil interceptor from the described oil groove of the described compressor of described the first compressor bank; Described oil interceptor fluid is connected in to the described compressor of described the second compressor bank; Pressure in described oil interceptor is increased on the suction pressure of described compressor of described the second compressor bank, to oil is supplied to the described compressor of described the second compressor bank from described oil interceptor.

The other exemplary embodiment of the present invention comprises and a kind ofly between at least two compressors of two different compressors groups, compensates oily method, and it comprises step: the oil level at least one compressor of monitoring the second compressor bank; And if the oil level in the described compressor of the second compressor bank drops to below predetermined minimum of a value, use is passed to oil the method for at least one compressor of the second compressor bank from least one compressor of the first compressor bank by oil interceptor, oil is passed to the described compressor of the second compressor bank from least one compressor of the first compressor bank.

The other exemplary embodiment of the present invention is included between at least two compressors of two different compressors groups and compensates oily method, and it comprises step: the oil level at least one compressor of monitoring the first compressor bank; And more than if the oil level at least one compressor of described the first compressor bank rises to predetermined maximum, use is passed to oil the method for at least one compressor of the second compressor bank from least one compressor of the first compressor bank by oil interceptor, oil is passed to the compressor of the second compressor bank from least one compressor of described the first compressor bank.

Accompanying drawing explanation

Exemplary embodiment of the present invention is described with reference to the accompanying drawings in more detail, wherein:

Fig. 1 shows the schematic diagram of the refrigerating circuit that comprises economizer;

Fig. 2 shows according to the oil subsidy of first embodiment of the invention and repays with the schematic diagram arranging;

Fig. 3 shows the schematic diagram of the refrigerating circuit that comprises economizer and refrigerating circuit; And

Fig. 4 shows according to the oil subsidy of second embodiment of the invention and repays with the schematic diagram arranging.

Specific embodiment

Fig. 1 shows the schematic diagram of the exemplary embodiment of refrigerating circuit 2, on the represented flow direction of the arrow in refrigerating circuit 2 by refrigerant circulation, described refrigerating circuit 2 comprises a set of compressor 4a of the first compressor bank of parallel join, 4b, 4c, heat rejection heat exchanger 6, economizer heat exchanger 14, high pressure valve or high-tension apparatus 17, coolant collector 18, bloating plant 8 and be connected in compressor 4a, 4b, the evaporimeter 10 of the suction of 4c (entrance) side.

On flow direction indicated by the arrow, refrigerating circuit 2 also comprises economizer, and described economizer has energy-conservation bloating plant 16, economizer heat exchanger 14 and energy-saving compressor 12.

For energy saving in running loop, from the part cold-producing medium stream of heat rejection heat exchanger 6 from the main flow bifurcated of cold-producing medium and expand by energy-conservation bloating plant 16.From the cold-producing medium being inflated of energy-conservation bloating plant 16, flow through the 14a of first of economizer heat exchanger 14, economizer heat exchanger 14 is for cooling from heat rejection heat exchanger 6 and flow to the main flow of refrigerant of high pressure valve or high-tension apparatus 17 by the second portion 14b of economizer heat exchanger 14, and the second portion 14b of described economizer heat exchanger 14 is against the part stream of the cold-producing medium being inflated.After leaving the 14a of first of economizer heat exchanger 14, the part of cold-producing medium stream by energy-saving compressor 12, compressed and with the pressure of compressor 4a, 4b with by the first compressor bank, 4c the supply system cryogen same (height) by the entrance for being back to heat rejection heat exchanger 6.

The cold-producing medium that flows through economizer is followed the cold-producing medium of the major part that flows through refrigerating circuit 2 different with the degree that bloating plant 8 expands by high pressure valve 17 by the degree of energy-conservation bloating plant 16 expansions.Energy-conservation evaporating temperature and compressor 4a, the 4b of pressure ratio the first compressor bank are therefore, evaporating temperature and the pressure of 4c are high.Therefore, the suction density in energy-conservation suction inlet is higher.

As previously discussed, this pressure reduction has caused compressor 4a, 4b, the 4c of oil from energy-saving compressor 12 to refrigerating circuit 2 only to transmit.

Fig. 2 shows the exemplary embodiment according to oily transmission mechanism of the present invention, and this oil transmission mechanism is configured to oil to be passed at least one compressor 12 with the second compressor bank of the suction pressure level run higher than the first compressor bank from compressor 4a, 4b, the 4c of the first compressor bank with low suction pressure level run.

Can be corresponding to compressor 4a, 4b, the 4c of refrigerating circuit 2 with compressor 4a, the 4b of first group of low suction pressure level run, 4c, and the compressor 12 of the second compressor bank can be corresponding to the energy-saving compressor 12 of the economizer shown in Fig. 1.

By cold-producing medium, suck circuit 3 and cold-producing medium is supplied to compressor 4a, 4b, the 4c of first group with low-pressure, and by high-pressure discharge circuit 5, compressed cold-producing medium is supplied to be back to refrigerating circuit 2 with high pressure.

Compressor 4a, the 4b of first group, each in 4c comprise oil groove 7a, 7b, 7c, and each oil groove 7a, 7b, 7c are defined to minimum oil level 9a, 9b, 9c.

Excessive oil circuit 22 leads to oil groove 7a, 7b, 7c above corresponding minimum oil level 9a, 9b, 9c, oil groove 7a, 7b, the 7c that makes compressor 4a, 4b, 4c each other fluid connects and makes oil groove 7a, 7b, 7c fluid be connected to oil interceptor 26, and described oil interceptor 26 is configured in described first kind hydraulic shrinking machine 4a, 4b, the level below 4c.

If the oil level at least one of described first kind compressor 4a, 4b, 4c is on corresponding minimum oil level 9a, 9b, 9c, excessive oil circuit 22 allows oil to flow into oil interceptor 26 from each oil groove 7a, 7b, 7c.

In the embodiment shown in Figure 2, oil interceptor 26 form that basic horizontal is arranged but with respect to level and the pipeline tilting a little, so that oil interceptor 26 has the upper end 26a being arranged in than on the high horizontal plane of bottom 26b.The fuel feeding circuit 30 that is connected in the bottom 26b of oil interceptor 26 is connected in oil interceptor 26 fluids on the compressor 12 of the second compressor bank, allows by oil groove 13 fuel feeding of the compressor 12 of fuel feeding circuit 30 from oil interceptor 26 to described the second compressor bank.Delivery valve 32 is arranged in fuel feeding circuit 30.If refrigerating circuit 2 only comprises the compressor 12 of second compressor bank, delivery valve 32 can be unidirectional check (non-return) valve, and but this unidirectional check (non-return) valve allows oil to flow to the compressor 12 of the second compressor bank from oil interceptor 26 do not allow oil from the compressor 12 of the second compressor bank, to flow into oil interceptor 26 in the opposite direction.If refrigerating circuit 2 comprises the compressor 12 of more than second compressor bank, switchable delivery valve 32(is magnetic valve for example) can be associated with each compressor 12 of the second compressor bank respectively, to selectively allow and do not allow oil to flow to the oil groove 13 of each compressor 12 of the second compressor bank from oil interceptor 26.

The upper end 26b of oil interceptor 26 is connected in compressor 4a, the 4b of the first compressor bank, the high-pressure discharge circuit 5 of 4c by high-tension line 36.Switchable high pressure valve 38 is arranged in described high-tension line 36, and this allows selectively by opening high pressure valve 38 to increase the pressure in oil interceptor 26 and oil interceptor 26 fluids are connected in to high-pressure discharge circuit 5.

Oil interceptor 26 also by low-voltage circuit 40, is connected in compressor 4a, the 4b of the first compressor bank, the cold-producing medium of 4c sucks circuit 3.Low-voltage circuit 40 leads to cold-producing medium by escaper 44 and sucks circuit 3, and this escaper 44 makes the pressure drop in low-voltage circuit 40 suck below the pressure in circuit 3 to cold-producing medium when operation.

Switchable low pressure valve 42 is arranged in low-voltage circuit 40, this allows, and selectively by opening, low pressure valve 42 is reduced to compressor 4a, the 4b of the first compressor bank by the pressure in oil interceptor 26, the value below the suction pressure of 4c, and oil interceptor 26 fluids is connected to the escaper 44 that is arranged in low-voltage circuit 3 places.

The end wall of oil interceptor 26 is respectively arranged with transparent detection glass 28a, 28b, with the oil that allows to collect in vision-based detection oil interceptor 26.

As discussed above, when refrigerating circuit 2 moves in the situation that economizer is actuated, due to the pressure reduction between the compressor 12 of compressor 4a, 4b, 4c and second compressor bank of the first compressor bank, oil is passed to compressor 4a, the 4b of the first compressor bank, the oil groove of 4c from the oil groove 13 of the compressor 12 of the second compressor bank.

The excessive oil gathering in order to be collected in compressor 4a, the 4b of the first compressor bank, in oil groove 7a, the 7b of 4c, 7c, switchable low pressure valve 42 is opened, and this makes oil interceptor 26 be connected to and be arranged in compressor 4a, the 4b of the first compressor bank, the cold-producing medium of 4c sucks the escaper 44 in circuit 3 by low-voltage circuit 40 fluids.

Escaper 44 is decreased to compressor 4a, the 4b of the first compressor bank, the value below the suction pressure of 4c by the pressure in low-voltage circuit 40 and oil interceptor 26.Due to this pressure reduction between oil interceptor 26 and compressor 4a, 4b, 4c, from compressor 4a, the 4b of the first compressor bank, the oil in the region of the minimum oil level 9a of oil groove 7a, the 7b of 4c, 7c, 9b, 9c top is inhaled into oil interceptor 26 by excessive oil circuit 22.Under this operational mode (receiving oily pattern), when oil is inhaled into oil interceptor 26 from compressor 4a, 4b, oil groove 7a, the 7b of 4c, the 7c of the first compressor bank, high pressure valve 38 and delivery valve 32 are closed.

If oil interceptor 26 is arranged in compressor 4a, the 4b of the first compressor bank, the horizontal plane of 4c below, difference in height can be enough large, thereby even can oil be passed to oil interceptor 26 from compressor 4a, 4b, the 4c of the first compressor bank with low-voltage circuit 40.In this case, the hydrostatic pressure difference between compressor 4a, 4b, 4c and oil interceptor 26 may cause that excessive oil flows into oil interceptor 26 from oil groove 7a, 7b, 7c.

For the compressor 12 from oil interceptor 26 to the second compressor bank transmits oil (it has been collected in oil interceptor 26 as previously described), when opening high pressure valve 38 and delivery valve 32, close low pressure valve 42(fuel feeding pattern).

Opening of high pressure valve 38 is connected in compressor 4a, the 4b of the first compressor bank, the high-pressure discharge circuit 5 of 4c by collector 26 fluids, and this has increased the pressure in oil interceptor 26.Be arranged in pressure that hole in excessive oil circuit 22 or check valve 24 avoided increasing in oil interceptor 26 is compensated to the first compressor bank immediately compressor 4a, 4b via

excessive oil circuit

22,4c.

Alternatively, the pressure that the oil of having collected in the 26b of the bottom of oil interceptor 26 under receiving oily pattern increases in by oil interceptor 26 by fuel feeding circuit 30 and the delivery valve 32 opened is pressed into the oil groove 13 of the compressor 12 of the second compressor bank, to improve the oil level 15 in the compressor 12 of described the second compressor bank.

Between the compressor 12 that is delivered in the second compressor bank that compressor 4a, 4b with the first compressor bank of relatively low suction pressure operation, 4c and the suction pressure with higher move of the compressor 12 of this oil from oil interceptor 26 to the second compressor bank, provide effective oil subsidy to repay.

After oil is passed to the compressor 12 of the second compressor bank from oil interceptor 26, close high pressure valve 38 to make oil stop flowing to from oil interceptor 26 compressor 12 of the second compressor bank.

Can be by reopening low pressure valve 42 and the pressure in oil interceptor 26 is decreased to compressor 4a, the 4b of the first compressor bank again, the value below the suction pressure of 4c, and use compressor 4a, the 4b from the first compressor bank, the oil in 4c that oil interceptor 26 is filled with again.

For technical staff, self-evidently, the embodiment shown in Fig. 2 can be similarly as a plurality of compressors 12 fuel feeding to the second compressor bank.The oil groove 13 of the compressor 12 of the second compressor bank can be connected to each other by oily compensated line.Alternatively, a plurality of fuel feeding circuits 30 can be connected to respectively oil interceptor 26 by each compressor 12.In this case, each compressor 12 of the second compressor bank can be independent of other compressors 12 of the second compressor bank and be supplied to from the oil in oil interceptor.

Can by means of be arranged in

oil groove

7a, 7b, 7c, 13 at least one in and/or be arranged in the oil sensor 34 in oil interceptor 26 and control described oily transmission method.When oil level that particularly oil level in one of them compressor of the second compressor bank drops to minimum oil level below 15 and/or in compressor 4a, the 4b of the first compressor bank, 4c or oil interceptor 26 has surpassed predetermined the highest oil level, can start oil transmission.

Fig. 3 shows the second embodiment of the refrigerating circuit 2 that comprises additional refrigerating circuit 54.

The feature of second embodiment identical with the feature of the first embodiment shown in Fig. 1 represents with identical Reference numeral, and no longer discusses in detail.

The cryogenic temperature producing outside the cryogenic temperature being provided by refrigerating circuit 2 is provided refrigerating circuit 54.Typical cryogenic temperature is at 0 ℃ within the scope of 10 ℃, and cryogenic temperature is typically in the scope of-20 ℃ to-5 ℃.

Refrigerating circuit 54 comprises the freezing bloating plant 52 that is connected in refrigerating circuit 2.Freezing bloating plant 52 is supplied to the part of refrigerant of circulation in refrigerating circuit 2.Described part of refrigerant is frozen bloating plant 52 and is expanded to even lower than the cold-producing medium being expanded by bloating plant 8 pressure, and by refrigerating evaporator 50 evaporation that is arranged in freezing bloating plant 52 downstreams, to be created in the cryogenic temperature below the temperature that the evaporimeter 10 by refrigerating circuit 2 produces.

After leaving refrigerating evaporator 50, the cold-producing medium of refrigerating circuit 54 is frozen compressor 4a, the 4b that compressor 48 is compressed to refrigerating circuit 2, suction (entrance) pressure of 4c, is compressed into the pressure identical with the cold-producing medium of evaporimeter 10 that leaves refrigerating circuit 2.Refrigerant condenser 48 is compressors of the 3rd compressor bank, it sucks (entrance) stress level and is less than compressor 4a, the 4b of refrigerating circuit 2, the inlet pressure of 4c, and outlet pressure level equals compressor 4a, the 4b of refrigerating circuit 2, suction (entrance) pressure of 4c.In this non-limiting example, freezing bloating plant 52, refrigerating evaporator 50 and refrigerant condenser 48 parallel joins are in bloating plant 8 and evaporimeter 10.

Fig. 4 shows the second exemplary embodiment according to oily bucking-out system of the present invention, and this oil bucking-out system can be in conjunction with the refrigerating circuit that comprises refrigerating circuit 54 2 as shown in Figure 3 and moved.

The feature corresponding with the feature of the first embodiment shown in Fig. 2 represents with identical Reference numeral, and no longer discusses in detail.

In the second embodiment shown in Fig. 4, the pressure reducing in oil interceptor 26 (it is provided to oil from compressor 4a, the 4b of the first compressor bank, oil groove 7a, the 7b of 4c, 7c suck oil interceptor 26) unlike in the first embodiment shown in Fig. 1 by utilizing escaper 44 that low-voltage circuit 40 is connected in to compressor 4a, the 4b of the first compressor bank, the cold-producing medium of 4c suction circuit 3 produce.

Alternatively, low-voltage circuit 40 fluids are connected in the entrance circuit 46 of the compressor 48 of the 3rd compressor bank, and the compressor 48 of described the 3rd compressor bank is the operation of suction (entrance) pressure below pressure with the suction (entrance) of compressor 4a, 4b in the first compressor bank, 4c.Pressure in oil interceptor 26 is decreased to compressor 4a, the 4b of the first compressor bank for this, the suction (entrance) of 4c below pressure, and makes oil flow to oil interceptor 26 from compressor 4a, 4b, oil groove 7a, the 7b of 4c, the 7c of the first compressor bank.

The compressor 48 of the 3rd compressor bank can be the refrigerating circuit 2(that is contained in as shown in Figure 3) in the refrigerant condenser 48 of refrigerating circuit 54.

Use its operation of suction pressure with compressor 4a, 4b lower than the first compressor bank, 4c of refrigerant condenser 48(of refrigerating circuit 54) reduce the pressure in oil interceptor 26, avoided compressor 4a, the 4b in the first compressor bank, the cold-producing medium of 4c to suck the demand that escaper 44 is set on circuit 3.Therefore, can save the cost that arranges and keep in repair escaper 44.

According to the refrigerating circuit of exemplary embodiment as described herein, allow to carry out compressor oil distribution in thering is the system of different crankcase pressures, and it is particularly suitable for HFC system and is suitable for sub level and the system of transcritical CO_2, although it is not limited to this.According to the refrigerating circuit of exemplary embodiment described herein, allow oil to be passed to second group of compressor with higher suction pressure operation from first group of compressor with low suction pressure operation, and because it has saved the oil eliminator of the on high-tension side costliness of compressor, so it is more cheap.In addition,, for transcritical CO_2 system, it has been eliminated the demand of Agglomerate Filter and maintenance.According to the refrigerating circuit of exemplary embodiment described herein, in the first compressor bank with the first suction level run and formation low pressure compressor, use excessive oil, in oil interceptor, collect excessive oil, and promote as required excessive oil in the second compressor bank with the second suction level run and formation high pressure compressor.

Should be appreciated that term " compressor bank " is the compressor that comprises any amount of only having a compressor.The number of the compressor of every compressor bank can be different.

Refrigerating circuit can comprise: economizer, and described economizer has energy-conservation bloating plant, and described energy-conservation bloating plant is for expanding from the part cold-producing medium stream of heat rejection heat exchanger; Economizer heat exchanger, the downstream that described economizer heat exchanger is arranged in heat rejection heat exchanger is partly flowed from heat rejection heat exchanger and is pointed to energy-conservation bloating plant and evaporimeter and a part for mobile cold-producing medium with the cooling cold-producing medium against expanding; And at least one compressor of the second compressor bank, it for being compressed to cold-producing medium part stream the outlet pressure of at least one compressor of first group before cold-producing medium part stream is supplied to pressure line.

Can magnetic valve or check (non-return) valve be set at least one compressor place of the second compressor bank.At least one compressor of the second compressor bank also can be called as energy-saving compressor.

Refrigerating circuit can comprise that the low-voltage circuit that is connected in oil interceptor is to reduce the pressure in oil interceptor.Reduce the pressure support ventilation in oil interceptor and strengthened oil to flow to oil interceptor from compressor.

Refrigerating circuit can comprise that at least one is connected in oil interceptor in the excessive oil circuit of at least one compressor of the first compressor bank.Excessive oil circuit allows oil to flow to oil interceptor from the compressor of the first compressor bank.

Excessive oil circuit can lead to the oil groove of the compressor of described the first compressor bank above the minimum oil level of the definition of described oil groove.The aperture arrangement of excessive oil circuit having been avoided above the minimum oil level of the hydraulic shrinking machine of the first compressor bank to by corresponding excessive oil circuit, from oil groove, extract oil causes oil level to be decreased to below minimum oil level.

High-tension line can be connected in the outlet side of at least one compressor of first group.At least one the outlet side that high-tension line is connected in to these compressors allows in the situation that do not need additional pressure generator/compressor to increase the pressure in high-tension line.

Refrigerating circuit can comprise choke valve or the check valve being arranged in excessive oil circuit.The choke valve or the check valve that are arranged in excessive oil circuit have avoided the pressure increasing in oil interceptor to pass through low-voltage circuit balance immediately.Otherwise it allows the pressure increasing in oil interceptor to be held a period of time, thereby oil is passed to the compressor of the second compressor bank from oil interceptor.

Refrigerating circuit can comprise the switchable valve being arranged in fuel feeding circuit, this switchable valve is connected in oil interceptor at least one compressor of the second compressor bank, to selectively allow and do not allow oil to flow between oil interceptor and at least one compressor of the second compressor bank.

Refrigerating circuit can comprise and is arranged in the switchable valve in low-voltage circuit and/or is arranged in the switchable valve in high-tension line, to selectively oil interceptor is connected in to high-tension line and low-voltage circuit, to allow selectively to increase and reduce the pressure in oil interceptor.The pressure that increases and reduce in oil interceptor allows to support oil to oil interceptor with from oil interceptor transmission.

Low-voltage circuit can be connected in the suction side of at least one compressor of the first compressor bank.Low-voltage circuit is connected in to the suction side of at least one in compressor and provides a kind of in the situation that do not need additional pressure regulating equipment to reduce the straightforward procedure of the pressure in oil interceptor.

Low-voltage circuit can be connected in escaper, and this escaper is arranged in the suction circuit of at least one compressor of the first compressor bank and is configured for the pressure reducing in low-voltage circuit.Low-voltage circuit is connected in to escaper allows pressure in low-voltage circuit and oil interceptor to be reduced to below the suction pressure of compressor of described the first compressor bank, to oil is sucked to oil interceptor from the compressor of the first compressor bank.

Refrigerating circuit also can comprise high pressure valve or high-tension apparatus and the refrigerant collecting container that is arranged in bloating plant upstream.This allows to provide the double expansion loop that comprises high-pressure section and intermediate pressure section.

Refrigerating circuit can comprise at least one compressor of the 3rd compressor bank that suction pressure is less than the compressor of the first compressor bank, and low-voltage circuit can be connected in the entrance side of at least one compressor of described the 3rd compressor bank.The suction pressure of the compressor of the 3rd compressor bank is less than the compressor of the first compressor bank, and this provides a kind of selection that low pressure is set in oil interceptor, to oil is sucked to oil interceptor from the compressor of the first compressor bank.

The compressor of the first compressor bank can be this compressor: it is configured to carry out normal refrigerating operaton being greater than at the temperature of 0 ℃, and the compressor of the 3rd compressor bank can be this compressor: it is configured for and carries out freezing operation being less than at the temperature of 0 ℃.This permission provides cryogenic temperature and cryogenic temperature with single refrigerating circuit.

Oil interceptor can have the form of the pipe of basic horizontal layout.Large quantity space easily be manufactured and do not occupied to the oil interceptor that forms pipe can with low cost, thereby it can easily be integrated in refrigerating circuit.The pipe that forms oil interceptor can arrange to allow the bottom at pipe to collect oil with respect to level a little obliquely.

High-tension line and/or low-voltage circuit can be to the open tops of oil interceptor.Because liquid oils will drop on the bottom of oil interceptor, this will make liquid oils and gas phase separation, and avoid in the cold-producing medium of gaseous state is imported into oil interceptor by high-tension line forming when increasing the pressure in oil interceptor foam.

Oil interceptor can be arranged in the horizontal plane of the compressor below of the first compressor bank.The horizontal plane that oil interceptor is arranged in to the compressor below of the first compressor bank, this allows oil from the compressor of the first compressor bank, to flow to oil interceptor by weight-driven.If the vertical distance between the horizontal plane of the compressor of the first compressor bank and the horizontal plane of oil interceptor is enough large, can not need the pressure in oil interceptor to be decreased to below the suction pressure of compressor of the first compressor bank, because oil is only passed to oil interceptor by gravity from the compressor of the first compressor bank.

Refrigerating circuit can comprise that at least one oil sensor is to determine the oil level at least one compressor and/or oil interceptor.Oil sensor allows the actual oil level based in hydraulic shrinking machine and/or oil interceptor and starts respectively and stop oily transmission, and this allows very efficient between compressor and accurately compensation is oily.

For the method that oil is passed to at least one compressor of the second compressor bank from least one compressor of the first compressor bank by oil interceptor, comprise step: the oil groove that oil interceptor fluid is connected to the compressor of the first compressor bank; The suction pressure of compressor that pressure in oil interceptor is reduced to the first compressor bank is following to oil is sucked to oil interceptor from the oil groove of the compressor of the first compressor bank; Oil interceptor fluid is connected in to the compressor of the second compressor bank; Pressure in oil interceptor is increased on the suction pressure of the compressor of the second compressor bank to oil is supplied to the compressor of the second compressor bank from oil interceptor.

The step that increases the pressure in oil interceptor can comprise the step that oil interceptor fluid is connected in to the outlet side of at least one in compressor.This is not in the situation that need additional supercharging equipment to increase the pressure in oil interceptor.

The step that reduces pressure can comprise the step that oil interceptor fluid is connected in to the entrance side of at least one in compressor.This is not in the situation that need additional pressure regulating equipment to reduce the pressure in oil interceptor.

The step that reduces pressure can comprise the step that oil interceptor fluid is connected in to the escaper in the suction circuit that is arranged in compressor at least one.This permission is reduced to the pressure in oil interceptor even below the suction pressure of described compressor.

Oil subsidy compensation method between at least two compressors can comprise that at least one compressor starting when the step of the oil level at least one compressor of monitoring the first compressor bank and the oil level in the compressor of the first compressor bank increase on predetermined value from least one compressor of the first compressor bank to the second compressor bank transmits oily step.

Oil subsidy compensation method between at least two compressors can comprise that the step of the oil level at least one compressor of monitoring the second compressor bank and the oil level in the compressor of the second compressor bank drop to the compressor that predetermined value starts when following from least one compressor of the first compressor bank to the second compressor bank and transmit oily step.This has been avoided reliably because oil consumption mistake causes the compressor of the second compressor bank to block or damage.

Although described the present invention with reference to exemplary embodiment, it will be appreciated by those skilled in the art that in the situation that not departing from the scope of the invention, can make various changes and can utilize equivalent to replace its element.In addition,, in the situation that not departing from essential scope of the present invention, can instruction according to the present invention make modification to adapt to special situation or material.Therefore, this means and the invention is not restricted to disclosed specific embodiment, but the present invention is by all embodiment that comprise in the scope that falls into claims.

Reference numeral

2: refrigerating circuit

3: suck circuit

4a, 4b, 4c: first kind compressor

5: high-pressure discharge circuit

6: heat rejection heat exchanger

7a, 7b, 7c: the oil groove of first kind compressor

8: bloating plant

9a, 9b, 9c: the minimum oil level of first kind compressor

10: evaporimeter

12: Second Type compressor

13: the oil groove of Second Type compressor

14: economizer heat exchanger

14a: the first of economizer heat exchanger

14b: the second portion of economizer heat exchanger

15: the oil level of Second Type compressor

16: energy-conservation bloating plant

17: high pressure valve

18: refrigerant collecting container

22: excessive oil circuit

24: check valve

26: oil interceptor

26a: the upper end of oil interceptor

26b: the bottom of oil interceptor

28a, 28b: detect glass

30: fuel feeding circuit

32: delivery valve

34: oil sensor

36: high-tension line

38: high pressure valve

40: low-voltage circuit

42: switchable valve

44: escaper

The entrance circuit of 46: the three groups of compressors

48: the three groups of compressors

50: refrigerating evaporator

52: freezing bloating plant

54: refrigerating circuit

Claims

1. a refrigerating circuit (2), it makes refrigerant circulation and comprises on flow direction:

At least one compressor of the first compressor bank (4a, 4b, 4c);

Heat rejection heat exchanger (6);

Bloating plant (8); With

Evaporimeter (10);

Described refrigerating circuit (2) also comprises:

At least one compressor (12) of the second compressor bank;

Oil interceptor (26), the described compressor (12) that described oil interceptor (26) can optionally be connected in the described compressor (4a, 4b, 4c) of described the first compressor bank and/or be connected in described the second compressor bank is collected excessive oil with described at least one compressor (4a, 4b, 4c) from described the first compressor bank;

Wherein, described oil interceptor (26) can optionally be connected in high-tension line (36) to increase the pressure in described oil interceptor (26), thereby oil is delivered to described at least one compressor (12) of described the second compressor bank from described oil interceptor (26).

2. refrigerating circuit according to claim 1 (2), wherein, the suction pressure of the described compressor (12) of described the second compressor bank is greater than the suction pressure of the described compressor (4a, 4b, 4c) of described the first compressor bank.

3. refrigerating circuit according to claim 1 and 2 (2), it comprises economizer, described economizer has:

Energy-conservation bloating plant (16), it expands from the part cold-producing medium stream of described heat rejection heat exchanger (6) for making;

Economizer heat exchanger (14), its downstream that is arranged in described heat rejection heat exchanger (6) is partly flowed from described heat rejection heat exchanger (6) and is pointed to described bloating plant (8) and point to described evaporimeter (10) and mobile cold-producing medium with the cooling cold-producing medium against expanding; And

Wherein, described at least one compressor (12) of described the second compressor bank was compressed to described cold-producing medium part stream the outlet pressure of described at least one compressor (4a, 4b, 4c) of the first compressor bank before described cold-producing medium part stream is supplied to pressure line.

4. according to the refrigerating circuit (2) described in above-mentioned any one claim, also comprise that the low-voltage circuit (40) that is connected in described oil interceptor (26) is to reduce the pressure in described oil interceptor (26).

5. according to the refrigerating circuit (2) described in above-mentioned any one claim, also comprise at least one excessive oil circuit (22), described at least one excessive oil circuit (22) is connected in described oil interceptor (26) by least one in the compressor of described the first compressor bank (4a, 4b, 4c), wherein, described excessive oil circuit (22) leads to the oil groove (7a, 7b, 7c) of described compressor (4a, 4b, 4c) on minimum oil level (9a, 9b, 9c).

6. according to the refrigerating circuit (2) described in above-mentioned any one claim, wherein, high-pressure discharge circuit (36) can be connected in the compressor (4a, 4b, 4c) of described the first compressor bank the pressure line (5) of at least one.

7. according to the refrigerating circuit (2) described in above-mentioned any one claim, also comprise the throttling or the check valve (24) that are arranged in described excessive oil circuit (22).

8. according to the refrigerating circuit (2) described in above-mentioned any one claim, also comprise the delivery valve (32) being arranged in fuel feeding circuit (30), described fuel feeding circuit (30) is connected in described oil interceptor (26) at least one compressor (12) of described the second compressor bank.

9. according to the refrigerating circuit (2) described in above-mentioned any one claim, also comprise the switchable valve (42) being arranged in described low-voltage circuit (40) and/or be arranged in the switchable valve (38) in described high-tension line (36).

10. according to the refrigerating circuit (2) described in above-mentioned any one claim, wherein, described low-voltage circuit (40) can be connected in the suction circuit (3) of at least one compressor (4a, 4b, 4c) of described the first compressor bank.

11. refrigerating circuits according to claim 10 (2), wherein, described low-voltage circuit (40) can be connected in escaper (44), and described escaper (44) is arranged in the suction circuit (3) of at least one compressor (4a, 4b, 4c) of described the first compressor bank and is arranged to the pressure reducing in described low-voltage circuit (40).

12. according to the refrigerating circuit (2) described in above-mentioned any one claim, also comprise high pressure valve (17) and refrigerant collecting container (18), described high pressure valve (17) and described refrigerant collecting container (18) are disposed between described heat rejection heat exchanger (6) and described bloating plant (8) on the flow direction of described cold-producing medium.

13. according to the refrigerating circuit (2) described in above-mentioned any one claim, at least one compressor (48) that also comprises the 3rd compressor bank, it has with the described compressor (4a, 4b, 4c) of described the first compressor bank compares lower suction pressure, wherein, described low-voltage circuit (40) can be connected in the entrance of at least one compressor (48) of described the 3rd compressor bank.

14. refrigerating circuits according to claim 13 (2), wherein, the described compressor of described the first compressor bank (4a, 4b, 4c) is the compressor (4a, 4b, 4c) that is arranged to normal refrigerating operaton, and the compressor of described the 3rd compressor bank (48) is the compressor that is configured for freezing operation.

15. according to the refrigerating circuit (2) described in above-mentioned any one claim, and wherein, described oil interceptor (26) has the form of the pipe of basic horizontal layout.

16. according to the refrigerating circuit (2) described in above-mentioned any one claim, and wherein, high-tension line (36) and/or described low-voltage circuit (40) are connected in the top of described oil interceptor (26).

17. according to the refrigerating circuit (2) described in above-mentioned any one claim, and wherein, described oil interceptor (26) is arranged in the level below the described compressor (4a, 4b, 4c) in described the first compressor bank.

18. according to the refrigerating circuit (2) described in above-mentioned any one claim, comprises that at least one oil sensor (34) is to detect in described compressor (4a, 4b, 4c, 12,48) oil level of at least one and/or the oil level in described oil interceptor (26).

19. are delivered to oil the method for at least one compressor (12) of the second compressor bank from least one compressor (4a, 4b, 4c) of the first compressor bank by oil interceptor (26), described oil interceptor (26) can optionally be connected in described compressor (4a, 4b, 4c, 12), and described method comprises step:

Described oil interceptor (26) fluid is connected in to the oil groove (7a, 7b, 7c) of the described compressor (4a, 4b, 4c) of described the first compressor bank;

Pressure in described oil interceptor (26) is reduced to below the suction pressure of described compressor (4a, 4b, 4c) of described the first compressor bank, to oil is drawn into described oil interceptor (26) from the described oil groove (7a, 7b, 7c) of the described compressor (4a, 4b, 4c) of described the first compressor bank;

Described oil interceptor (26) fluid is connected in to the described compressor (12) of described the second compressor bank;

Increase the pressure in described oil interceptor (26) and/or reduce the suction pressure of the described compressor (12) of described the second compressor bank, so that the pressure in described oil interceptor (26) becomes larger than the suction pressure of the described compressor (12) of described the second compressor bank, to oil is supplied to the described compressor (12) of described the second compressor bank from described oil interceptor (26).

20. methods according to claim 19, wherein, increase the step of pressure in described oil interceptor (26) and comprise and described oil interceptor (26) fluid is connected in described compressor (4a, 4b, 4c, 12,48) to the pressure line of at least one.

21. according to the method described in claim 19 or 20, wherein, reducing the step of pressure in described oil interceptor (26) comprises and described oil interceptor (26) fluid is connected in described compressor (4a, 4b, 4c, 12,48) to the suction circuit of at least one.

22. according to the method described in claim 19 or 20, wherein, reducing the step of pressure in described oil interceptor (26) comprises described oil interceptor (26) fluid is connected in to the escaper (44) in the suction circuit that is arranged in described compressor (4a, 4b, 4c, 12,48) at least one.

Between 23. at least two compressors two different compressors groups (4a, 4b, 4c, 12), compensate oily method, comprise step:

Monitor the oil level at least one compressor (12) of the second compressor bank; And

If the oil level in the described compressor (12) of the second compressor bank drops to below predetermined minimum of a value, right to use requires the method described in 19 to 22 any one, oil is passed to the described compressor (12) of described the second compressor bank from least one compressor (4a, 4b, 4c) of the first compressor bank.

Between 24. at least two compressors two different compressors groups (4a, 4b, 4c, 12), compensate oily method, comprise step:

Monitor the oil level at least one compressor (4a, 4b, 4c) of the first compressor bank; And

If the oil level at least one compressor of described the first compressor bank (4a, 4b, 4c) rises on predetermined maximum, right to use requires the method described in 19 to 22 any one, oil is passed to the compressor (12) of the second compressor bank from least one compressor (4a, 4b, 4c) of described the first compressor bank.