SU1134856A1 - Working medium for low-temperature compressor refrigerating machine - Google Patents

Abstract

WORKING BODY FOR A LOW-TEMPERATURE COMPRESSION REFRIGERATING MACHINE containing freon-23 and normal butane, characterized in that, in order to increase the specific cooling capacity and increase the suction pressure, it additionally contains freon-14 in the following ratio of components, mol. %: Freon-145-15 Freon-2320-45 Normal butane Rest

Description

The invention relates to compositions of low-temperature compression refrigeration machines created on the basis of volumetric compression compressors (e.g. rotary piston, screw, membrane) both with lubricant and without lubrication of parts of compression cavities, piston-cylinder pairs), and can be used for cooling at the level of 177 - 207 K receivers of infrared radiation, in electronics, cryomedicine. Working fluids can also be used in large-scale refrigeration units, for example, in the food and chemical industries.

It is known to use in low-temperature compression chillers to obtain the cooling temperatures of 177-207 K for freon-503 (R 503), which is an azeotropic mixture of freon-23 (R23) and freon-13 (R13) (a mixture of trfluoromethane with trifluorochloromethane). This mixture, which is widely used in the low-temperature technique, has a high latent heat of vaporization, a lowered normal boiling temperature, and a low cooling capacity of 11.

A disadvantage of the known mixture (R503) is the need to use FM 5.5 AP oil with low anti-wear properties.

In addition, the compressor on the R503 has a high tem. Literary strength of the windings in the built-in motor.

Closest to the invention is a working fluid containing freon-23 (R23) and normal butane (RGOO). The use of this mixture allows an 8-fold increase in the cooling capacity of the low-temperature compression refrigeration mailina compared to R503 2.

The disadvantages of this mixture (R23-R600) are the relative large costs of specific power and the need to maintain a low suction pressure to ensure the desired cryostat temperature, which can lead to a vacuum in the evaporator and air entering the system .

The aim of the invention is to develop such a working temperature, which at higher suction pressure has an increased value of specific cooling capacity and low power consumption for compression.

This goal is achieved by the fact that the working fluid containing freon-23 and normal butane additionally contains freon-14 (R14) at the following ratio O / F of the components, mol.

freon-14 5-15.

Freon-3320-45

Normal Butane Else

 The drawing shows the phase equilibrium diagram.

As follows from the diagram, at a constant temperature, for example, T 192 K (average temperature of the cooling temperature range 177-207 K of the working fluid) and there is an AVSD region of immiscibility R14, R23 and R600, which characterizes the change in the composition of the liquid phase of the mixture depending on from the content in it of a light-grade unit component, i.e., R14. Constant pressure lines (three dot-dashed segments), which correspond to suction pressure, are drawn inside the AVSD region. The presence of a wide area of immeasurability of the worker

the body causes its boiling point in the evaporator of the refrigerating machine when the suction pressure of the compositions changes, if they are taken from the AVSD area where R14, R23 and R600 are not mixed in the liquid phase, is constant. To ensure maximum cooling performance at temperatures of 1 to 5 x levels of 177-207 K and at pressures exceeding atmospheric, in the field of possible compositions of AVSD it can be distinguished

optimal compositions avsde (shaded

The presence in the working body of the R600 allows

for the lubrication of the hermetic compressor

work on a mixture of R14 - R23-R600, as with

work on a mixture of R23-R600, use refrigeration oil HF 22c-16, the antiwear qualities of which are 3 times better than the corresponding qualities of low-temperature oil FM-5.6 AN.

R-working body for chiller

prepared by the weight method.

In clean, vacuumed and pre-weighted cylinders recruit a specified number of pre-cleaned R14, R12 and R600. After that, each of the cylinders is attached to the stand and by means of cooling in liquid nitrogen, the components are recondensed into the receiver of the cooling machine. Then cylinders with insignificant residues of pure R14; R23 and R600 are weighed to clarify the concentration of the prepared working fluid.

As a result of the research, it was established that the described working body with a higher suction pressure, but a slightly lower degree of compression than that of R23-R600, allows to reach the same cooling temperature, ensuring a cooling capacity of 1.54 times greater. This is due to the fact that the magnitude of the isothermal choke effect increases due to a shift in operating pressures.

chiller to higher values and use in large quantities a substance such as P600, which has a high eigenvalue

, 1134856.

34

Throttle Effect. When using the pre-consumed power 1.4 times, the cost of the working fluid is about 1.45 times the cooling capacity compared to

does not work with suction pressure with a system on R23-R600 with the same chla0, 22 MPa; significantly higher than at-productivity. With an annual obsospheric and, thus, exclusive production of 1000 products, the air is released into the system. The effect of harming this mixture

On the proposed refrigeration mixture for low-temperature compression

the machine has a lower mass by 1.3 times; the cooling mash is 218,000 rubles.

Claims (1)

WORKING BODY FOR A LOW TEMPERATURE COMPRESSION REFRIGERATING MACHINE, containing Freon-23 and normal butane, characterized in that, in order to increase the specific cooling capacity and increase the suction pressure, it additionally contains Freon-14 in the following ratio of components, mol. %: Freon-14 5-15 Freon-23 20-45 Normal Butane Else 134856