FR2467009A1 - PROCESS AND PROCESSING MACHINE IN SOLVENT MEDIUM - Google Patents

Abstract

Process and machine for treatment in a solvent medium allowing the use of high-boiling point solvents in which the solvent present in the articles at the end of the treatment is recovered by circulating by fan a current of air which passes through these articles in the basket then passes over a cooled condenser. Said condenser is the evaporator of a refrigerating machine, the air, once cooled and free of solvent, then being sent to the condenser of said refrigerating machine to be returned in a closed circuit to the fan and to the basket and in which one operates in two phases, namely a first phase in which said air is reheated to a first temperature prior to its return to the basket by passing it over the condenser of the refrigeration machine and a second phase in which the temperatures prevailing in the condenser and evaporator of said machine are shifted downwards by the use of an auxiliary condenser supplied with water at ambient temperature and suitably placed on the refrigerant circuit, downstream of the compressor. (CF DRAWING IN BOPI)

Description

The invention relates to machines for treating solvents or

  solvent medium, for example for cleaning, degreasing, embossing, finishing, fireproofing, waterproofing of various articles, such as clothing or fabrics.

  In such machines, after the operation of arm-

  wise with the solvents, it is necessary to wring then to dry

  articles by recovering the residual solvent by evaporation

  tion. Conventional dry cleaning equipment

  perform this operation in two stages.

  At first, the drum or basket is traversed by a stream of air heated to 800C approximately propelled by a fan; this air causes a large part of the solvents that are recovered by cooling the air in

  a condenser. At the temperature of 800C, there is a risk of

  stain fixation, felting or denaturing

  articles, detachment of bonded liners.

  The second operation, which is called deodoro-

  This is followed by a circulation of fresh air which, after having passed through the articles, is sent to the atmosphere. The clothes temperature is lowered but remains around 50 - 550C,

  which is not favorable to their handling or appearance.

  This process has, in addition, other disadvantages: - It causes a high energy consumption, both to heat the air sent in the articles than for then

cool it down.

  - It also leads to significant water consumption

in the condenser.

  - During deodorization, it causes

inadmissible.

  - It causes appreciable consumption of solvents

which are expensive products.

  Various means have been recommended to overcome these disadvantages.

  It has been suggested that the air be deodorized

  adsorbents, such as activated carbon, to improve recovery and reduce pollution. But

  this process is energy intensive in the regeneration phase.

coals.

  It has been proposed to replace perchlorethylene, the most used solvent, with a solvent with a lower boiling point in order to reduce energy consumption (fluorinated solvents). But these solvents are more expensive and of poor efficiency. Their low boiling point causes greater loss through accidental evaporation; they are little used except for special applications, such as

  than cleaning skins and very fragile items.

  In order to improve the use of these low-boiling solvents, it has already been recommended to use

  the condenser, the refrigerant of a refrigerating machine

  that the capacitor serves for heating the solvent.

  The whole forms a closed thermodynamic system, the refrigerating machine operating in heat pump transferring the calories from the condenser to the heater (French patent

  No. 2,035,303, U.S.A. Patent No. 3,070,463).

  There is no need for deodorization operation,

  the operating temperature of the condenser being sufficiently

  low for virtually total recovery of the solvent

closed circuit.

  We thus obtain a relative saving of energy and

  solvents and a decrease in pollution.

  But this solution is not applicable to soil

  boiling point, such as perchlorethylene,

  lene, trichlorethylene, trichloroethane etc ...

  For the latter, it has been proposed to use a refrigerant condenser, or a water condenser associated with a refrigerant condenser, these two

  condensers mounted in series or in parallel.

  In French Patent No. 2,130,523, the refrigerated condenser is used for the deodorization, the recovery being as known. This refrigerated condenser is mounted in

parallel on the heater.

  In French Patent No. 2,293,513, the condenser

  refrigerated comes after the water condenser to lower the temperature

  air temperature and decrease the limit of the concentration of

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  saturation of the solvent. During this operation the heater

  of the air circuit is bypassed.

  This results in solvents with a high boiling point

  the problem of energy saving is not solved, due to the increased energy expenditure caused by the refrigerated condenser, and the consumption of energy.

water remains high.

  The method and the machine according to the invention are characterized in that the air circulates in closed circuit and passes successively, out of the basket, on the evaporator and then on the condenser of a refrigerating machine which comprises, on the upper part pressure of the refrigerant circuit downstream of the compressor, an auxiliary condenser fed with water or with pulsed air and one operates in two phases, a first phase in which the auxiliary condenser is not powered and a second phase in which the auxiliary condenser

is powered.

  In the first phase, especially when the solvent is perchlorethylene, the air at the entrance of the basket is worn

  at a temperature of the order of 55 to 600.degree.

  erature is preferably accelerated by an auxiliary heater.

  thermostatically controlled. The evaporator temperature is then GoC

  approximately and most of the solvent is recovered.

  In the second phase the auxiliary condenser has the effect of lowering the temperature of the air at the entrance to the basket, either by lowering the temperature of the condenser of the refrigerating machine, or by acting as the latter, which

  : O is then bypassed. The temperature of the evaporator is

  drop at a temperature below -100C, almost all the remainder of solvent is recovered, while the temperature

  clothes at the end of the basket is lowered.

  This achieves all the objectives sought - Use of high-boiling solvents - Energy saving; - water saving; Solvent saving

- Suppression of pollution.

  The invention will be described in greater detail below with reference to the appended drawing in which: FIG. 1 is a diagram of a first variant embodiment; Figure 2, a diagram of a second embodiment. If we refer to the diagram in FIG.

  sees that the machine has a drum or basket 1, in the-

  which of the air can be sent by the fan 5. For simplicity the drawing comprises only a circular path while it is, in known manner, a closed chamber

  in which there is a rotary basket of circular section.

  In 2 is a dust filter on the exhaust duct 15 of the air. Downstream of the filter 2, the air is sent to the evaporator 3 of a refrigerating machine which serves as a condenser and the solvent is recovered at 16. Then this air, freed of solvents, is sent to the condenser 4 of said machine refrigerant that warms it and returned to the basket 1 by the fan 5. Air circulates as well

closed circuit.

  The refrigerating machine comprises a compressed group

  7 which sends via line 21 a refrigerant

  such as Freon in the condenser 4 where it cools, to be then sent into the evaporator 3 after expansion in the expander 11 after which the fluid is returned to the

  compressor 7 through line 20. In 8 is an exchange

  thermal energy, which can, as known, be replaced by a

  capacity located between the compressor 7 and the condenser 4.

  In 9 is a dehydrator and in 10 a passing light

fluid.

  This assembly constitutes a heat pump with which is associated an auxiliary condenser 12 placed upstream of the condenser 4 and in which the coolant is cold water circulating in the controlled pipe 17

by the valve 13.

  In addition, there is provided between the fan 5 and the basket 1 an auxiliary heater 6, for example a backup resistance, provided with thermostatic control means, by

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  example a probe placed in the basket 1 (not shown).

Operation is as follows

First phase.

  The compressor unit 7 is started simultaneously without circulation of water in the auxiliary condenser 12; - The fan 5; - The auxiliary heater 6, set to a temperature

of the order of 500C.

  The circulating air in closed circuit is heated by the condenser 4 and then by the auxiliary heater 6, so that the temperature in the basket rises rapidly to about 500C. This rise in temperature is achieved in a few minutes (about 3 'to 5') and the auxiliary heating can then be interrupted: the rise in temperature continues

  then by the sole effect of the main condenser.

  The air becomes saturated with solvents when passing over

  ticles which leads to a drop in temperature. Its temperature at the end of the basket is of the order of 30 C to 450C. It then passes on the dust filter 2, then on the evaporator 3 of the refrigerating machine which is at a similar temperature

from 00C.

  This first phase lasts about 15 to 20 minutes

  and at least 95% of the solvent is recovered.

  To avoid overpressure in the refrigerant circuit

  A valve 14 may be provided, equipped with regulation means, either by a thermostatic probe 18 in the air stream downstream of the condenser 4, or directly by the compressor outlet pressure measured at 19. This valve sends to the condenser 12 a flow of cold water to maintain the high pressure of the refrigerating machine below the maximum chosen.

Second phase.

  Following this first phase, the equi-

  free of temperatures by circulating water using the valve 13 in the auxiliary condenser and removing

auxiliary heating 6.

  The temperature of the air passing through the fan 5 and entering the basket 1 is gradually lowered to

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  a temperature below 300C. As a result, it is somewhat warmed by the clothes in the basket.

  warming being of the order of a few degrees.

  In the evaporator 3, the temperature of the air falls to about 150.degree. C. and the remainder of solvents remaining in the

clothes is condensed.

  When lion opens the basket at the end of the pass the time

  The temperature of the articles is less than 300C (which is suitable for their handling and appearance) and the solvent content

  at opening is less than 100 parts per million.

  By way of example, the comparative table, below, of different machines using perchlorethyleneillustrates the advantages of the invention:

A = Consumption.

  B = Classic machine processing 10 kg of clothing

by pass.

  C = refrigerated condenser machine 10 kg / pass.

  D = Machine according to the invention 10 kg / pass.

  The diagram of FIG. 2 differs from the diagram of FIG. 1 by the situation of the auxiliary condenser 12 on the

refrigerant circuit.

  While in Figure 1 the condenser 12 is in series with the condenser 4 and upstream thereof, in the diagram of Figure 2, it is mounted in parallel the valves 22 and 23 for sending the fluid out of the compressor either through the condenser 4 (valve 22 open, valve 23 closed) or through the condenser 12 (valve 23 open, valve 22 closed). So we go from the first to the second phase by actuating the valves 22 and 23 and the water supply 13. An auxiliary valve 24 may be provided to regulate the circulation of Freon or other refrigerant and by

A B C D

  Electricity 32 KwH 4.33 KwH 1.54 KwH

Water 100 1. 96 1. 43 1.

Solvent 750 gr. 180 gr. 150 gr.

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  following the temperature of the evaporator 3.

  In the second phase according to this variant, the condenser 4 is not powered and the air passing through it is not heated, which lowers the sequence of temperatures in the air circuit.

  The figures given in the foregoing description

  refer to perchlorethylene, the most used solvent; solvents whose boiling point is not far from that of perchlorethylene. In the case of using other solvents, the optimum temperatures for each phase and the characteristics of the refrigerating fluid to be used will be determined by some tests, the method and the machine of the invention being flexible enough to allow this adaptation. . Although the process and the machine of the invention have been designed to allow the use of high boiling solvents, they can also be used with

  low boiling solvents.

R E Y E N D I C A T I 0 N S

  1.- Method of treatment in a solvent medium, in particular

  with a high-boiling solvent, in

  the solvent present in the articles at the end of

  is recovered by circulating a fan

  air flow through these items in the basket and then pass

  on a cooled condenser, characterized in that said condenser

  It is the evaporator of a refrigerating machine, the air once cooled and freed of solvent then being sent on the condenser of the refrigerating machine to be returned in a closed circuit to the fan and the basket and in that one operates in two phases namely a first phase in which

  said air is warmed to a first temperature prior to

  on returning to the basket by passing it over the condenser of the refrigerating machine and a second phase in which the temperatures prevailing in the condenser and evaporator of said machine are shifted downwards by the use of an auxiliary condenser supplied with water at room temperature and suitably placed on the refrigerant circuit,

downstream of the compressor.

  2. A process according to claim 1, characterized in that the rise in temperature of the first phase is accelerated with the aid of an auxiliary heater provided with thermostatic means. 3. Process according to claim 2, characterized in

  that said thermostatic means are set for a time

  at least 500C at the entrance of the basket, tan-

  say that the temperature of the evaporator is of the order of about 00C.

  4. Process according to any one of the claims

  in which the lowering of the air temperature at the entrance of the basket during the second phase reaches

values from 100C to 300C at least.

  5.- Machine treatment in a solvent medium allows

  both the use of high-boiling solvents of the type in which the articles are treated with the solvent in a rotary basket and means are provided to cross this basket and the articles it contains by a current

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  of air forced by a fan and for cooling the air flow in a condenser at the outlet of the basket, characterized in that the air flow is in a closed circuit, the air passing over the evaporator of a machine refrigerant, with solvent recovery means and the condenser of said machine, to be returned to the basket under the action of a fan and that an auxiliary condenser supplied with water at room temperature is mounted on the circuit of fluid

  of said refrigerating machine downstream of the compressor.

  6. Machine according to claim 5, characterized in that a thermostat-controlled auxiliary heater is placed on the air flow downstream of the condenser of the

refrigerating machine.

  7. Machine according to any one of the claims

  5 and 6, characterized in that the auxiliary condenser is connected in series with the condenser of the refrigerating machine and upstream of the latter and provided with means for ensuring or

  interrupt the circulation of water at will.

  8. Machine according to any one of the claims

  5 and 6, characterized in that the auxiliary condenser is connected in parallel with the condenser of the refrigerating machine

  and valves are provided for passing the refrigerant

  Gene under pressure at will, either through the condenser

  located on the air circuit, either through the condenser auxi-

iary.

  9. Machine according to any one of the claims

  to 8, characterized in that the auxiliary condenser is used to regulate the temperature or the pressure of the high pressure circuit of the refrigerating machine by means of a valve

  controlled by said temperature or pressure.