DE2153651C3 - Hot gas defrosting device for refrigeration systems - Google Patents

Description

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Configurations of the subject matter of the invention characterizing the compressor 10 leads, and above that from the

draws. Evaporating refrigerants in vapor form

The invention will be seen in the following with reference to the compressor 10 is returned,
matic drawings of exemplary embodiments The refrigeration system described works in detail. It shows 5 known ways, that is, the evaporator of each cooling

Fig. 1 schematically a typical refrigeration system, the direction takes heat from the cooling device or

forms an embodiment of the invention, the refrigerated goods located therein, so that the

F i g. 2 schematically shows a second embodiment refrigerant is heated and evaporated, resulting in formation

of the invention and frost or ice on the evaporator tube snakes

Fig.3 schematically leads a third embodiment io. The numerous evaporators of the refrigeration system «

the invention. lead to a cumulative latent heat exposure

To illustrate the invention, the refrigeration returned to the compressor will be stung below refrigerant gas forming a closed circuit, and this heat load exceeds location, which is a high level of the amount of heat that is required for an odei stungseinrichtung for multiple operation acts, 15 defrost several of the evaporators 21 to 24; these how they z. B. is used in a supermarket to heat quantity is occasionally called "warm clean." larger number of separate cooling devices, marked "shot".

e.g. refrigerated storage and storage boxes, to It is desirable to periodically check each vaporizer operate. It is clear, however, that for a short period of time, but completely, Such a refrigeration system can also be defrosted for other commercial or industrial applications in order to remove the accumulated frost Purposes can serve. The expressions gen. To make this possible, a hot gas “High pressure side” and “low pressure side” are provided in fire line 30, by means of which gaseous following in the refrigerant total from the delivery line 13 of the Verübfichen in the field of refrigeration technology Sense used to select those parts of the poet 10 from the evaporator tube facility to designate that can be fed between the conveyor queues, and the one via Abseite of the compressor and the evaporator expansion branch lines 31 with the three-way valves 28 sion valves are arranged. or those parts, is connected; in Fig. 1 this is the two together allocated between the expansion valves and volume evaporators 23 and 24 the suction side of the compressor. Three-way valve 28 is shown in its defrosting position.

The in F i g. 1 illustrated refrigeration system comprises 30 The speed of defrosting does not depend on at least one compressor 10, instead of which a plurality of compressors could only be provided on the delivery side of the compressor. addable amount of heat, but also after that with a suction or low pressure side 11, which works with a predetermined suction pressure present along the evaporator to be defrosted, and the pressure difference through which the refrigerant is released from the delivery or high pressure side 12, the evaporator to flow through. The line 13 is connected through which the hot. Arrangement for generating this required compressed gaseous refrigerant a condensate pressure difference comprises a normally offetor 14 is supplied. In the condenser 14 is nes solenoid valve 32, which is in the delivery line 13 de; the refrigerant is brought to its condensation temperature and its condensation pressure in the direction of flow behind the compressor. The condensate collector 17 is connected to a condensate collector 17, which is connected to a bypass line 33 which feeds the refrigeration system and supplies the liquid source for the liquid solenoid valve 32 bridged. In this reverse refrigerant forms. The outlet 18 of the condensate line is a differential check valve 34 collector 17 is connected to a liquid judgment line 45, which is connected to a pressure in the area in front of 19, which is used to set the liquid refrigerant to about 1.05 to 2.8 atmospheres , so that the pressure tel branch lines 20 and 20 a, are connected to the hot gas distributor line 30 during the deviation, the evaporator coils 21, 22, 23 and thaw the pressure on the high pressure side of the con 24, which are connected to the various non-capacitor 14, the condensate collector 17 and you are assigned cooling devices shown. 50 distribution line 19 by a predetermined amount Although FIG. 1 only exceeds four evaporator coils. The condensate that arises from the refrigerant during defrosting, however, can be connected to the high-pressure side by additional evaporators. A magnet 35 and a check valve 36 are fed back into the cooling system via a further bypass line branch line 20 for each evaporator. The branch lines 20 a 55 that bridge the relevant evaporator are shown in FIG. 1 represents the associated expansion valve 26 as interrupted lines to indicate that the length of this line connects the return line 37 between the machine room and the condensate in question, which according to FIG. 1 is indeterminate with the Forfenden cooling device. Furthermore, the line 13 is provided on the high pressure side between the expansion valves 26, through which the quay 60 condenser 14 and the differential pressure valve 34 are connected to the evaporators in a known manner.

will measure. The evaporator outlets are during normal cooling operation at dei

by suction branch lines 27, which are also sub-embodiment according to FIG. 1 of the compressor 10 and

fallows are shown standing at their indefinite length under high pressure and at a high

to indicate, with three-way valves 28 and refrigerant vapor at 65 temperature at the

normal cooling operation via these valves and condenser 14 via line 13 and the nor

further branch lines 27 ″ with a common, sometimes open, solenoid valve 32. The refrigerant

Suction line 29 connected, the steam to Saiigseile 11 is in the condenser on the condens

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Cooled sation temperature and brought to the condensate usually components of the line arrangement in the system pressure, in order to then get to the condensate machine room, while the branch lines collector 17, which forms a source for the liquid 120 a over an indefinite length to the various refrigerants , with which the evaporator 21 to the cooling devices in the supermarket erbis 24 via the distribution line 19, the branch lines 5 stretch. In view of this, the bypasses 20, 20e and the expansion valves 26 are fed lines 135 and the check valve 136, which are. In the evaporator, the refrigerant takes the expansion valve 126 bypassed, in the heat concerned, so that it evaporates and provided via the fenden cooling device, and the condensate arising in the branch line 27, 27 a, the three-way valves 28 and defrosting flows through the suction line 29 again flows to the suction side of the compression bypass line and the branch line 120 α to the ters 10. Engine room back. Since the solenoid valve 125

If a defrosting process is to be carried out while the defrosting process is closed, a

the solenoid valve 32 is closed, and the upper bypass line 140 is provided, which the

Matching three-way valve 28 is switched to branch line 120 a via a check valve 141

Hot gas manifold 30 and the relevant 15 mil of manifold 137 for defrosting Branch line 31 connects to the resulting condensate via the three-way valve,

chose to connect vaporizer. If the Ma- F i g. 2 also shows that in this embodiment

solenoid valve 32 closed, the delivery pressure takes the form of a device 143 for separating fluid

of the compressor 10 compared to the pressure in fluid and steam is provided that a T-piece

the direction of flow behind the differential pressure 20, which between the manifold 137

valve 34 to until the pressure is exceeded, and a compensation line 144 is arranged, the

the valve 34 is set so that the valve from the condensate collector 117 to the top of the

til 34 opens long enough so that a sufficient capacitor 114 leads, and in the usual

Can flow through the amount of refrigerant in the manner of a check valve 145 is switched on. That

maintain a predetermined pressure difference. »5 T-piece 143 comprises an expanding pipe

When the hot gas enters the cold section 146 to be defrosted, which enters the equalization line 144 Evaporator enters, it is condensed, and the switch is, and one is at right angles to it Pressure in the evaporator increases until it reaches the un- extending pipe socket 147 into which the associated

lower differential pressure in the condenser 14, the other end of the manifold 137 with sealing

proceeds, whereupon the condensed refrigerant 30 is built into action; in the tee is a self

Arranged via the bypass line 35 and the non-return pipe bend 148 opening downwards,

valve 36 and the condensate collecting line 37 through which the condensate formed during defrosting

the condenser 14 flows back, in which all is fed approximately directly to the condensate collector 117

remaining vapor is condensed, so that is.

the condensed refrigerant to the condensate target in the embodiment according to FIG. 2 a collector 17 flows, from which the evaporation thawing process can be carried out, the magnet is remotely supplied to the other cooling devices. valve 132 closed to maintain a constant pressure

F i g. 2 shows a second embodiment of the difference at valve 134 between hot detection, in which the parts of the refrigeration system each with gas distribution line 130 and the point of cold anum 100 cause increased reference numbers corresponding to the position in 40, which is in the direction of flow The reference numerals used in Fig. 1 are denoted; is behind the valve 134. The vaporous refrigeration, the actual refrigeration system, can also be formed by means of the evaporator 122, for example be like the one on the basis of FIG. 1 and is directed to defrost it, ir it normally works just like the latter to remove a mixture of condensate and steam passing over the Generate cold eg. To illustrate the erfln- 45 bypass line 135 and the check valve However, instead of each other in pairs 136. the branch line 120 a, the bypass line associated evaporator 21, 22 and 23, 24 three ge 140 and the check valve 141 to the condensate-separated cooling device * evaporator 121, 122, 123 collecting line 137 flows, which is shown in the machine, and the evaporator 122 forms the space to the T- Piece 143 leads. The condensate will Defrost selected evaporator. 50 introduced directly into the condensate collector 117.

The hot gas defrosting device shown in FIG. 2 during the steam phase in the usual way also includes an arrangement for generating through the equalization valve 144 and allowing a pressure differential to flow to the condenser 114 with a solenoid valve 145 132, which are condensed again in the delivery line 113 of the compressor nm. 110 is switched on, as well as with a bypass line. 55 FIG. 3 shows a further embodiment tang 133 and a Differentialventfl 134 zmn Er refrigeration system, the parts of which, each with ran 288, generate a predetermined pressure difference between reference symbols corresponding to the ones shown in FIG. 1 provided of hot gas distribution 130 and the upside-down numbers are designated; the actual pressure side of the condenser 114, which in turn corresponds to the Ex- borrowing refrigeration system, of the valves 126 of the evaporators 121 to 123 shown in FIG. 1, and she usually works in the SB-associated. According to Figure 2, however, the arrangement is borrowed to generate cold. Corresponding tion to return the defrosting caused by defrosting. 2, the evaporator 222 is designed differently in FIG. 3 than that from the condensate. The liquid thawing evaporator selected. Supply branch lines 120 to the magnetron with the hot gas defrosting device according to FIG do 125 to shut off the 63 selected for defrosting, the arrangement for starting a diur vaporizer, in which it is skn according to FIG. 2 on the difference in the üuiigig behind the Kon evaporator 122 acts, from the normal supply capacitor 214 or between the Kondenor and of the refrigerant arranged above the distribution line 119 form the condensate collector 217, and the

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Hot gas distribution line 230 is established and maintained on the delivery line without the 213 of compressor 210 being connected. The delivery pressure of the compressor on undesired fire line 230 can, however, also increase in the streamling manner, whereby the suction load of the device arranged behind the condenser 214 is stabilized more densely and with additional lasein, but it must be transported on the high pressure side in the 5 tentative heat which can be used for defrosting the flow direction upstream of the valve 234 for generating.

be provided gene a pressure difference. From the above description it can be seen

the embodiment according to Fi g. 3 is the manifold that the delivery pressure on the compressor 10 and the

device 237 for the resulting condensation pressure on the condensate collector 17 during defrosting

sat also connected to line 215, and essentially the same in normal cooling operation

although between the capacitor 214 and the Kon- is. Initially, due to the low temperature

Densatammler 217, ie in the direction of flow door and the low pressure steam over the hot

downstream of the differential pressure valve 234 so that the gas distribution line 30 leads to the selected evaporators

Condensate generated during defrosting goes directly to the 23 and 24, but flows out of the evaporators

Condensate collector 217 is returned, in which 15 only steam to the high pressure side if a

the liquid phase separated from the vapor phase pressure difference between the delivery pressure of the

will. Another improvement compressor shown in Fig.3 and the pressure on the high pressure side

tion consists in the use of steam extraction on the condensate return line,

line 250, in which a normally closed- When the solenoid valve 32 is in the delivery line

Nes solenoid valve 251 and a withdrawal regulator 252 ao 13 when initiating a defrosting process closes, goes

are switched on; the line 250 extends between the pressure in the condenser 14, in which

in the condensate collector 217 and the condensate collector 17 and in the collecting line 19

denser 21 · leading suction or collecting line 229. back immediately, while the delivery pressure of the

The operation of the hot gas defrosting device 10 begins to increase as soon as the

according to FIG. 3 is similar to that of the previously mentioned pressure difference between both sides of the

Written embodiments, apart from that, differential valve 34 reaches the value to which this

that the separation of the liquid and the vapor valve is set, the refrigerant flows through

takes place in the condensate collector 217 , so that a the differential valve on the high pressure side to the

Supply of liquid refrigerant is present, the condenser and the condensate collector as well

is immediately available and in the usual 30 through the hot gas distributor line 30 to the

Let the remaining evaporators 221 and 223 be thawing evaporators, and this pressure difference

can not be defrosted. is kept during the entire defrosting period

To prevent the pressure from being maintained in the condenser.

satammler 217 rises during defrosting, which is what occurs during a defrosting process.

condensate leading to an increase in the delivery pressure of the compressor 35 is returned directly to the high-thickness

would lead, which is possibly undesirable, are passed back to the supply of liquid cold

a balanced weight is produced by adding tempants so that the returned calf

Steam from the condensate collector 217 of the suction means directly to the cooling devices again

page 211 of the compressor 210 is metered. At can be supplied without a steam of the embodiment according to FIG. 3 cause the 40 phase to go through; this makes a strong one

Vapor extraction regulator 252 and the solenoid valve maintain refrigerant flow so that the

251 that the predetermined pressure difference quickly increases the efficiency of the refrigeration system

1 sheet of drawings

Claims (5)

can optionally be connected to a hot gas line 1. Hot gas defrosting device for refrigeration systems, pressure line of the compressor arranged valve at least one unit branches off on the high pressure side, which the pressure line for the time Compressor, a condenser and a condenser 5 of the defrosting to a higher pressure than inj Nordensatammler as well as malbetrieb on the low pressure side and thus have a pressure difference between several evaporators, which can be optionally connected between the compressor outlet and the condenser Hot gas line can be connected, which is generated in satsammler, with the defrosting one Direction of flow in front of one in the pressure line of the evaporator opposite to the north Compressor arranged valve unit io paint direction flowing refrigerant in the branches off that the pressure line for the time of the cycle of the other evaporators flowing through-defrosting can be traced back to a higher pressure than in the north of the refrigerant. Malbetrieb and thereby a pressure difference in a known refrigeration system of this type between the compressor outlet and the con (USA. Patent Specification 3 464 226) that is generated at the Abdensatsammler, whereby the condensate of one of the evaporators that occurs when defrosting one of the evaporators is opposite to this or the condensate-gas mixture directly into the unfortunately normal Direction flowing through cooling for liquid refrigerant initiated, from which the medium in the circuit of the other evaporator remaining in the normal refrigerant circuit remaining refrigerant flowing through the refrigerant are supplied dampers. However, since defrosting is characterized in that the 20 of an evaporator not only accumulates condensate, but also when defrosting an evaporator (21, 22, 23; the not 121, 122, 123; 221, 222, 223) that accumulates, especially at the end of the defrosting period con- konaensiertes refrigerant gas in under a gedensat or condensate and gas mixture through a ringeren pressure than the hot gas line standing Kälbesondere line (37; 137; 237) downstream reaches temittelieitung, it can cause interference in the by the valve unit (32, 33, 34 ; 132, 133, 134; 25 refrigerant supply line to the evaporators involved in defrosting not 232, 233, 234) and upstream of the condenser,
satsammler (17; 117; 217) in the refrigerant The invention is therefore based on the object cycle is recyclable. the refrigerant supply to the 2. Hot gas defrosting device according to claim 1. Vaporizers also during defrosting a «; the characterized in that the valve assembly 30 ensure evaporator. (32, 33, 34; 132, 133, 134; 232, 233, 234) from For this purpose, the invention provides that the a normally open solenoid condensate or condensate-gas mixture, which occurs during defrosting of an evaporator during defrosting, which can be closed by a valve (32; 132; 232) , to which a "special line downstream of the valve assembly pressure difference between the compressor outlet 35 and upstream of the condensate collector in and the condensate collector (17; 117; 217) he refrigerant circuit can be returned.
convincing check valve (34; 134; 234) par- This line routing ensures that Everyone! is switched. that does not condense when defrosting an evaporator 3. Hot gas defrosting device according to the claims refrigerant passed through the condenser Chen 1 and 2, characterized in that liquefied in the 40 and there, so that the evaporators not involved in defrosting an evaporator (121, 122, thawing process) are only liquid 123) accumulating condensate or condensate refrigerant is fed. Gas mixture receiving special line In another known refrigeration system (USA.- (137) a device (143) for separating patent specification 3 150 498) is a sub-cooling of the liquid and gas is provided, from which the condensate is vorgese-liquid behind the condensate collector in the condensate collector (117) and hen, so that the Defrosting an evaporator into the gas in the refrigerant supply line to the condenser, which reaches the Versator (114) that is not involved in the defrosting process. Refrigerant fed in line carrying steam. 4. Hot gas defrosting device according to the claims, as long as it is vaporous, is condensed. In those 1 to 3, characterized in that the 50 ser known system is a special cooler for valve assembly (232, 233, 234) between which the condensate is required, but without the Si condenser (214) and the condensate collector is given security that no vaporous cold (217) is arranged. medium enters one of the evaporators. This is too 5. Hot gas defrosting device according to claims then the case when, as is also known, the calves 1 to 4, characterized in that the 55 temitteldampf flows through a longer line together suction side (211) of the compressor (210) with the liquid coolant , because depending on the condensate collector (217) via a line (250) which can be switched off when the line is cut and the temperature of the condensation of an evaporator (221, 222, 223) is used, the condensation of the coolant is connected into which a be different. In practice, however, it is impossible for steam extraction regulator (252) to be built in. 60 compliance with a satisfactory operating condition, e.g. B. at a modern supermarket, too ensure where the from the engine room to the Cooling devices leading both lines The invention relates to a hot gas defrosting short as well as long lines, their device for refrigeration systems, which on the high pressure length 65 depending on the installation site of the side at least one compressor, a condensate various cooling devices in the supermarket gate and a condensate collector as well as directed towards the opposite of the engine room.
Low-pressure side have several evaporators, which are advantageous features in the subclaims