RU2151972C1 - Combined system with nitrogen cooling - Google Patents

Abstract

FIELD: cooling equipment. SUBSTANCE: cooling machine of combined system with nitrogen cooling comes in the form of Stirling machine. Closed circuit of re-condensation of vapors of liquid nitrogen houses nitrogen vessel, evaporator, intermediate heat exchanger, expansion turbine, expansion vessel, refrigerating machine, Dewar flask, high-pressure pump and check valve placed in series. Tap connects gas part of nitrogen vessel with intermediate heat exchanger and evaporator. Closed working circuit of gaseous nitrogen incorporates cooled heat-insulated space housing nitrogen distribution and collection system and compressor. Compressor is coupled to expansion turbine via clutch. Refrigerating machine can be driven by electric motor, separate thermal engine or engine of vehicle. EFFECT: provision for thermostating of various objects with high level of explosion and fire risk, for fast cooling and long-term storage of food products and other materials in nitrogen atmosphere.

Description

 The invention relates to the field of cryogenic technology and cryogenic refrigeration machines operating on the reverse Stirling cycle, can be used for thermostating of various objects and long-term storage of food and other materials.

 There are known technical solutions of gas turbines in which the energy of compressed gas is converted into work at the same time as the gas temperature decreases (Chechetkin A.V., Zanemonets N.A. Heat engineering: Textbook for chemical and technical special universities. - M. : “Higher School.” 1986. - p. 307).

 Known technical solutions for the gasification of liquefied gases before distributing them to consumers using high pressure pumps (Questions of deep cooling / Sat. Articles edited by prof. MP Malkov /. Ed .: "Foreign literature", M., 1961, pg. 287 - 288).

 Known technical solutions for emptying cryogenic containers by the self-pressurization method, in which part of the liquid is supplied to the evaporator, for heat exchange with atmospheric air and the transition to a gaseous state with increased pressure, and returns to the tank in the free space above the liquid (R. F. Barron. Cryogenic systems 2nd ed., Edited by AK Gorodov, Moscow: Energoatomizdat. 1989. - p. 323).

 A device of the Dewar vessel for liquid nitrogen with vacuum-powder insulation is known (Sokolov E.Ya., Brodyansky V.M. Energy fundamentals of heat transformation and cooling processes: Textbook for universities. - 2nd ed., - M.: Energoizdat 1981, p. 202).

 It is known that in the range of cryogenic temperatures (60 - 160 K), the reverse Stirling cycle is the most highly efficient cycle. The efficiency of cryogenic Stirling machines is almost 2 times higher compared to other plants used for gas liquefaction (Usyukin IP Plants, machines and apparatuses of cryogenic technology. M: Light and food industry, 1982., pp. 185 - 186) .

 A device of the gas refrigerating machine "Philips", operating on the reverse Stirling cycle, designed to liquefy the air and includes a block of heat exchangers: a condenser, a regenerator and a refrigerator. Helium is used as a working fluid in the refrigeration machine (Questions of deep cooling / Collected papers, edited by prof. MP Malkov /. Ed .: "Foreign Literature", Moscow, 1961, p. 35). However, liquid air has an increased fire hazard.

 It is known that nitrogen is a chemically inactive substance, it is not toxic and can be used to create an inert environment due to its explosion and fire safety (Glinka N.L. General chemistry: Textbook for universities. - 22nd ed., Rev. L .: " Chemistry ", 1982. - pp. 398 - 399). However, nitrogen production is an expensive process.

 A known system of nitrogen cooling in a heat-insulated car body, designed to transport products and allows you to quickly cool the internal volume of the body. The system includes a container with liquid nitrogen and a submersible centrifugal pump for feeding liquid nitrogen into the cooled chamber, while the nitrogen medium has a beneficial effect on the stored products (Akulov L.A., Borzenko E.I., Soloviev V.A. Nitrogen system cooling in a heat-insulated car body. // Abstracts of the international scientific and technical conference "Refrigeration in Russia. Status and Prospects on the Eve of the XXXI Century" //, St. Petersburg, 1998. - p. 32.) However, this system involves emission used nitrogen into the atmosphere that bring t to irretrievable loss of expensive gas - nitrogen.

 A device for cooling products is known that contains a closed loop for condensing liquid nitrogen vapor, including a nitrogen tank with gas and liquid parts, a control valve for supplying nitrogen from the tank to the evaporator, and a refrigeration machine (Patent GB N 1179796, F 25 D 3/10, 1970 ) However, this technical solution does not use the highly efficient Stirling refrigeration cycle.

 The technical result that can be obtained by carrying out the invention is to exclude irretrievable loss of nitrogen, the possibility of using the system for thermostating of various objects with a high level of explosion and fire safety, quick freezing and long-term storage of food and other materials in a nitrogen atmosphere.

 To achieve this technical result, a combined system with nitrogen cooling containing a closed loop for condensing liquid nitrogen vapor, including a nitrogen tank with gas and liquid parts, a control valve for supplying nitrogen from the liquid part of the tank to the evaporator, as well as a refrigerating machine, is equipped with a liquid vapor condensation loop nitrogen sequentially placed by an intermediate heat exchanger installed after the evaporator, an outlet connecting the gas part of the nitrogen tank to the intermediate a heat exchanger and with an evaporator, an expansion turbine, an expansion tank connected to the Dewar vessel through a refrigeration machine made in the form of a Stirling machine, a high pressure pump and a non-return valve, and the system is equipped with a closed working loop of gaseous nitrogen passing through the intermediate heat exchanger and the evaporator, and containing a cooled thermally insulated volume with a nitrogen distribution and collection system located therein, and a compressor connected to an expansion turbine through a coupling cl captured, wherein the drive of Stirling refrigerating machine may be carried out by a motor, separate from the heat engine or a vehicle engine.

 Introduction into the combined nitrogen cooling system of a closed working loop of gaseous nitrogen with a compressor and a nitrogen distribution and collection system in the refrigerated volume and, in the liquid nitrogen vapor condensation circuit, of an intermediate heat exchanger installed after the evaporator, a vent connecting the gas part of the nitrogen tank to the intermediate heat exchanger and with an evaporator, an expansion turbine, an expansion tank connected to the Dewar vessel through a refrigeration machine made in the form of a Stirling machine, on a high pressure wasp and a non-return valve, it is possible to obtain a new property consisting in eliminating the release of nitrogen into the environment and compensating for heat influx from the cooled products by transferring heat from the closed working loop of gaseous nitrogen to the closed loop of condensation of liquid nitrogen vapors, and nitrogen vapor is condensed in condenser stirling chiller.

 The drawing shows a combined system with nitrogen cooling.

 The combined system consists of a closed loop for condensing liquid nitrogen vapor, which includes a nitrogen tank 1, a control valve for supplying liquid nitrogen 2, an evaporator of liquid nitrogen 3, a branch 4 connecting the gas part of the tank 1 with an intermediate heat exchanger 5 and an evaporator 3, an expansion turbine 6, expansion tank 7, Stirling refrigeration machine 8, including a condenser 9, a dewar vessel 10, a high pressure pump 11, a check valve 12, and a closed working loop of gaseous nitrogen passing through the intermediate a weft heat exchanger 5 and an evaporator 3, and consisting of a compressor 13 connected to an expansion turbine 6 through a clutch 14, and a nitrogen distribution and collection system 15 located in a thermally insulated cooled volume 16. A vehicle engine can be used to drive the Stirling refrigeration machine 8, an electric motor or a separate heat engine (not shown in the figure).

 Combined system with nitrogen cooling works as follows.

 Due to external heat inflows and heat inflows from the cooled products to the gaseous nitrogen of the closed working circuit, it is heated in the cooled volume 16, cooling its internal environment. From the volume 16, warm nitrogen is supplied by means of a compressor 13 to an intermediate heat exchanger 5, where it is partially cooled, and then enters the evaporator 3, where it is further cooled to low temperatures due to heat exchange with liquid nitrogen, and enters the nitrogen distribution and collection system 15 located in volume 16. In addition to the quick freezing of products and thermostating of volume 16, the nitrogen environment has a beneficial effect on long-term storage of food products. Due to heat exchange with gaseous nitrogen from the closed working circuit to the evaporator 3, the liquid nitrogen of the closed condensation circuit is heated and evaporates, which leads to the formation of high-pressure vapors. From the evaporator 3, gaseous nitrogen of high pressure simultaneously enters through the outlet 4 into the gas part of the tank nitrogen 1, to supply liquid nitrogen from the liquid part of the tank 1 to the evaporator 3, the flow is regulated by valve 2, and into the intermediate heat exchanger 5, where it overheats, due to heat exchange with nitrogen in a closed working circuit, with increasing pressure. Then the heated nitrogen enters the expansion turbine 6, where it expands with decreasing temperature, while the useful work generated is spent on the drive of the compressor 13 connected to the turbine 6 through the clutch 14. From the turbine 6, nitrogen enters the expansion tank 7, from which gaseous nitrogen is sucked into the condenser 9 of the Stirling refrigeration machine 8, where it condenses, passing into the liquid phase, and merges by gravity into the Dewar vessel 10, from where it is fed back to the nitrogen through the check valve 12 1 container.

Sources of information taken into account when preparing the application:
1. Chechetkin A.V., Zanemonets N.A. Heat engineering: Textbook. for chem. - technol. specialist. universities. - M .: "Higher School", 1986. - p. 307.

 2. Issues of deep cooling. / Sat articles edited by prof. M.P. Malkova. Publisher: "Foreign Literature". M., 1961, p. 287 - 288.

 3. R.F. Barron. Cryogenic systems. 2nd ed. under the editorship of A.K. Gorodova. M .: "Energoatomizdat", 1989. - p. 323.

 4. Sokolov E. Ya., Brodyansky V.M. Energy fundamentals of heat transformation and cooling processes: Textbook. manual for universities. - 2nd ed., - M.: Energoizdat. 1981, p. 202.

 5. Usyukin I.P. Installations, machines and apparatuses of cryogenic equipment. M .: Light and food industry, 1982, pp. 185 - 186.

 6. Issues of deep cooling. / Sat articles edited by prof. M.P. Malkova. Publisher: "Foreign Literature", M., 1961, p. 35.

 7. Glinka N. L. General chemistry: Textbook for universities. - 22nd ed., Rev. L .: "Chemistry", 1982. - pp. 398 - 399.

 8. Akulova L.A., Borzenko E.I., Soloviev V.A. Nitrogen cooling system in a thermally insulated car body. // Abstract. reports of international scientific - tech. conf. "Refrigeration technology in Russia. Status and prospects on the eve of the XXXI century" //, St. Petersburg, 1998. - p. 32.

 9. Patent GB N 1179796, F 25 D 3/10, 1970. - prototype.

Claims (1)

 Combined system with nitrogen cooling, containing a closed loop for condensing liquid nitrogen vapor, including a nitrogen tank with gas and liquid parts, a control valve for supplying nitrogen from the liquid part of the tank to the evaporator, as well as a refrigerating machine, characterized in that the refrigerating machine is made in the form of a Stirling machine , the condensation circuit is equipped with a sequentially placed intermediate heat exchanger installed after the evaporator, an outlet connecting the gas part of the nitrogen tank to the intermediate a heat exchanger and with an evaporator, an expansion turbine, an expansion tank, a Dewar vessel connected through a Stirling machine to an expansion tank, a high pressure pump and a check valve, and the system is equipped with a closed working loop of gaseous nitrogen passing sequentially through an intermediate heat exchanger and evaporator and containing a cooled thermally insulated the volume with the nitrogen distribution and collection system located in it, and the compressor connected to the expansion turbine through the clutch, drive the Stirling refrigerating machine can be carried out by a motor, separate from the heat engine or a vehicle engine.