FR2626657A1 - DEVICE FOR PERMANENT MONITORING OF REFRIGERATING MACHINES AND REFRIGERATING FACILITIES - Google Patents

Abstract

Device allowing the permanent monitoring of a refrigerating machine or installation with a compressor operating by evaporation and liquefaction of an evolving fluid which takes its heat of vaporization from the cold utilization liquid. A temperature sensor is permanently placed in the oil sump of compressor S1, on the latter's discharge pipe S2 and on its suction pipe S3. Application to the prediction of the risk of breakdowns.

Description

As is known, the frequency and compressor machines comprise a

  evolution circuit of a suitably selected fluid, which comprises an evaporator and the fluid, introduced into the liquid state, passes to the gaseous state by absorbing the state-changing calories, - a compressor raising the pressure of the gas , a bonded factor where the compressed and suitably cooled gas is liquefied, and a pressure regulator preceding the return of the fluid into the evaporator.

  The calories absorbed by the fluid in the evapo-

  are taken on a liquid, brine or water-

  glycol, which circulates in the premises & cool and that one

  will call hereinafter use liquid.

  It happens that abnormalities of operation, initially insidious and undetected & time, lead to sudden breakdowns requiring the replacement of parts and subassemblies and immobilizing the machine. full

work time.

  The plaintiff has posed the problem of being able to detect anomalies in a simple way, whereas they are still at their beginning, so that the big ones

  repairs can be scheduled in advance.

  He found - which was not obvious - that this problem could be solved by the observation of thermometric probes, mounted permanently at points

  suitably chosen machine or installation.

  The indications of these probes, constituted for example by thermistors, can be transmitted to a central point where it will be easy to monitor and compare them. They can also be transformed

in alarm signals.

  The main probes are associated with cockroach

  which causes the most frequent failures, one sensor being placed in the oil sump, another on the compressor discharge and a third on the compressor.

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  aspiration. For a given machine, it has been observed that the temperatures at the three designated points stabilize during operation at a determined value, which depends on the type of the installation, whereas an anomaly, either mechanical or in the physical state of the fluid evolutionary aspire, results in an increase in the temperature of the repressed gas or the temperature of the oil. crankcase,

  or by a decrease in the suction temperature.

  In these three probes, it is advantageous to add a fourth probe placed on the outlet of the liquid.

  of use cooled in the evaporator.

  It is still advantageous to add two other probes placed respectively at the outlet of the liquefier on the path of the fluid and at the entrance of the water.

  cooling the liquefier.

  The description that follows, next to the drawings

  annexes, given as an example, permpttra of good com-

  take how the invention can be realized.

  Figure 1 shows a diagram of an installation

  refrigerant equipped according to the invention.

  Figure 2 shows schematically the grouping

  indications from the probes.

  In Figure 1, we see in 1 the evaporator o

  the evolutionary fluid chosen, for example the monochlorodi

  fluoromethane (Freon 22), passes to the gaseous state by absorbing

  the calories of change of state, in 2 the compres-

  the aspirator which sucks in the gas formed in the evaporator, in 4 the liquefier which receives by the gas discharged by the compressor and returns it in the liquid state, finally, at 7, the regulator which lowers the pressure of the fluid before

his return to the evaporator 1.

  The circuit for using the frigories produced in the evaporator starts at 8 and returns to 9. The incongruable liquid of this circuit is generally constituted by a mixture of water and glycol. According to the invention, three thermometric probes

  S1, S2, S3 are associated with the compressor 2.

  One of these probes S1, placed in the compressor housing, indicates the temperature. lubricating oil. The probe S2, placed on the discharge 5 of the

  compressor, gives the temperature of the gas discharged.

  Elevation of either or both of these temperatures, above the temperature generally observed in steady state operation, detects a compressor malfunction, such as a malfunction of a valve or poor circulation of the compressor. oil -10 greasing. For example, it has been observed that

  installation o the temperature of the gas exiting the compres-

  It is normally between 87 and 90 ° C, a temperature rise of 95oC indicates the need for the visit of the valves.

of the compressor and change them.

  The third probe S3, placed on the suction - of the compressor, must normally indicate a rather low temperature, since it is that of evolving gaseous fluid leaving the evaporator. But it may happen that the flow rate in the use circuit connected to 8 and 9, is insufficient, for example as a result of fouling, to bring into the evaporator -calories required & the complete vaporization of the fluid evolution * In this case, the compressor sucks by 3 a mixture

  gas and liquid, which is harmful to its function.

  ment. The lowering of the temperature indicated by the

  S3 probe will detect this risk of failure.

  For example, in the case of freon, the temperature at S3 is normally 4 ° C. and a lowering exceeding 20 ° C.

  must alert the supervisor of the installation.

  This probe 83 may advantageously be completed

  by a probe S.4 placed on the outlet 8 of the use liquid leaving the vaporizer. The aforementioned anomaly will be even better detected by the differential comparison of the indications provided by the probes 83, 84. This anomaly will indeed have the effect of

  result of decreasing the difference in the temperatures

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  these probes, which is normally 3 & 50C.

  It is furthermore possible to have two other probes $ 5 and S6 respectively on the path of the evolutive fluid exiting the liquefier 4 and on the inlet 10 of the cooling water of said liquefier, which is in general of the water at the temperature ambient drawn on

the distribution network.

  An anomaly in the functioning of the

  In the case of the use of "freon 22" the difference between the temperatures indicated by the probes $ 5 and S6 and re is, for example, that of the liquefier 4, the normal difference being 20C, so that

  that a difference greater than 40C must be considered abnormal

the

  The thermometric probes used being generally

  thermistors & platinum wire, fed by a constant potential, give an electric current

  intensity is a measure of temperature.

  It is therefore easy to group the galvanometers, giving the temperatures to the different points, on the same board installed at a central point as shown in Figure 2. The mobile crews of these galvanometers may even raise an alarm when their position will correspond to an anomaly considered dangerous. For the

  probes such as S3 and S2 as well as S5 and S6, which require

  a differential observation, it will be easy to foresee an electronic assembly reflecting the difference

  indications and providing an alarm when the vari-

  this difference crossed a threshold.

  -5- 1 CVN1ATl01qS 1. Device for the permanent monitoring of a compressor machine or refrigeration system operating by evaporation and liquefaction of a fluid

  evolutionary which takes its heat of vaporization on the li-

  use of the cold, characterized in that a thermometers probe is permanently arranged in the oil sump of the compressor (S1), on the tuhulure of

  backflow of this <S2) and on its suction pipe.

tion (S3).

  2. Device according to claim 1. caraci-risé

  in that a fourth probe (84) is placed on the tuhu

  lure by which the use liquid comes out cooled

of the evaporator (1).

  3.Device according to one of claims 1 or

  2, characterized in that two other probes $ 5, 86} are placed respectively on the pipes through which the evolutionary fluid leaves the liquefier and the fluid of

  refrigeration of this liquefier comes out of it.

  4.Device according to one of the preceeding claims

  characterized in that the probes are heat

  supplying an electric current according to the

  temperature and in that the apparatuses giving the temperatures

  erased by the value of the currents produced are groups

at one point of the installation.