CS257899B1 - Method of motor vehicles' heating boxes cleaning from incrustation choking - Google Patents

Abstract

these are mainly bus cabinets, with a circulating liquid heating medium cooling circuit and solve the problem restoring the heat exchange of these cabinets. In the first the degree of purification to the flow channels of heating the cabinet poured the mixture, consisting first of all from 0.2 wt. corrosion inhibitor solution based on amines or arylsulfoxides or xanthangens, or thiourea and from 4 to 10% wt. inorganic acids, optionally in admixture with carboxylic acid in a 1: 1 ratio. Inkrusty is then chemically and for 60 to 120 minutes they mechanically erode and release, and then the remaining mixture is drained and the flow channels are flushed with water until deposits are released. In the second stage, it is poured into the flow channels 2 to 6 wt. a solution of amine salts acids and release and flushing channels is repeated. If necessary, the third Repeat the cleaning procedure using 3 % to 5 wt. of an alkanedioic acid solution in an environment of 3 wt. mineral acids.

Description

BACKGROUND OF THE INVENTION The present invention relates to a method for cleaning heating cabinets of motor vehicles clogged with incrustations, in particular bus cabinets, with a heating circuit medium consisting of a coolant circuit.

In cold weather, heating cabinets mounted in the front wall of the vehicle are used to heat the interior of the buses, both for passengers and drivers. The heating cabinets consist of flat cuboid bodies made of non-ferrous metal alloys and the size of which depends on the vehicle type. The bodies have horizontal flow channels through which the coolant circuit is forced through the pump and thus the body is heated. Air is forced into the vehicle through the heating cabinet while driving or blowing.

The efficiency of the described heat exchange is reduced mainly by clogging the interior of the heating cabinets with incrustations and corrosion products. This fouling is further increased by the use of an unsuitable circulating medium and during the summer, when the liquid does not recirculate over the body and this is nevertheless periodically heated and cooled by the operation. The horizontal placement of flow channels, the so-called honeycombs, also plays a role.

The throughput of the heaters gradually decreases for the circulating liquid until the heat exchange capability is virtually completely lost, which is observed in most heaters after about two years of operation. Due to the small cross-section of the honeycombs, the mechanical removal of the incrusts cannot be carried out, so the only repair method currently consists in replacing the body or the entire heating and cooling head unit.

The above-described drawbacks eliminate clogged incrustations, in particular of the cooling circuit housings.

a method of cleaning the heating boxes of motor buses, with a heating medium of vehicles consisting of liquid

According to the invention, a mixture consisting of 0.2% by weight is poured into the flow channels of the heating cabinet in the first stage. an amine-based corrosion inhibitor solution of the formula R-NH- or arylsulfoxides RSR or ROC xanthogenates wherein R is alkyl • A ^SMMe / ^KI 2 ° or aryl, or thiourea S = C and said mixture consists of 4 to 6 10% wt.

^X 1 NH ₂ inorganic acids, e.g. hydrochloric HCl, optionally inorganic and carboxylic acids, e.g. acetic, in a 1: 1 ratio. Thereafter, the incrusts are etched and released chemically and mechanically for 60 to 120 minutes, for example with shaking, and then the resulting mixture of effluents and flow channels are flushed with water until deposits are released.

Subsequently, in a second stage, 2% to 6% by weight of ^{R1 is} poured into the flow channels of the same heating cabinet. a solution of an amine ethanoic acid salt of the formula N-CH-CH ₃ -N wherein R represents acyl a

Me.R ^X R.Me the release of increments and flushing through the flow channels is repeated in the same manner as in the first stage.

According to the invention, from 3 to 5% by weight is also poured into the flow channels of the heating cabinet in the third stage as required. % solution of an alkanedioic acid of formula (COOR) ₂ , wherein R is H or alkyl, in an environment of 3 wt. mineral acids, such as hydrochloric HCl or nitric HNO ₃ , whereupon the residual deposits are released and the solution is flushed with water. At the beginning of each wash cycle, the wash and rinse solutions as well as the heating cabinet are heated to a temperature of 50 to 80 ° C.

The cleaning method according to the invention will restore the desired heat exchange efficiency of the heating cabinets without having to replace them with new ones. This saves not only custom bodies made of non-ferrous metal alloys, but also other parts. It will also shorten the repair time considerably and facilitate its technical execution. Restoring the heater function will improve the traveling culture, the working conditions of the drivers and the safety of the road, as the windshields and side windows in the driver's compartment are not frozen.

In carrying out the process of the invention, the outer surfaces of the housing, if clogged, are first cleaned by wetting with an organic solvent, preferably based on hydrocarbon halide derivatives, or in aqueous detergent solutions at a total concentration of 1% by weight.

After 15 minutes of action, the compositions are flushed with hot pressurized water. The actual cleaning of the interior of the heating cabinets, which are decisive for the efficiency of the heat exchange, takes place in several stages, the number of which depends on the degree and type of contamination of the heating element. The first operation utilizes the dissolving effect of inorganic acids such as hydrochloric HCl, or inorganic and carboxylic acids such as hydrochloric and acetic, hydrochloric and formic HCl: CH ₃ COOH, HCl: HCOOH in a ratio of 1: 1, preferably up to 10% by weight of the total concentration and with the addition of an amine-based corrosion inhibitor of the formula R-NH4 or arylsulfoxides of the formula RSR, xanthogenans of the formula

O

ZX ^NH 2

R-O-C, thiourea of formula S = C

It has a concentration of 0.1-0.2% by weight. In the second step, the internal surfaces are cleaned using solutions containing chelating agents which are based on aminoethanoic acid salts of the formula (N-CH.-CH.-N ^ / ²⁾ .

Me.R R.Me ^x wherein R is alkyl or aryl, in the range of 4% to 6% by weight. The third operation, which is classified according to the condition of the contaminated body and is not always necessary, utilizes the solubility and olatation effect of the alkanedioic acids of the formula (COOR ^ at a concentration of 5% by weight in dilute mineral acids (HCl, HNO ^) up to 3% by weight. dissolution and washing are performed for sixty minutes and the solutions used are poured warm into heated bodies, all at 70 ° to 80 ° C. The solutions of the first and third operations are used up to five times after solid phase separation and replenishment of the active ingredient concentration. according to the invention, hot water is flushed according to the invention and the heat output can be determined by measuring the temperature of the air which is blown through the heated body.

The following are some examples of cleaning the heating cabinets according to the method of the invention.

Example 1

The bus heating box, according to preliminary inspection, was moderately clogged, clear, outer sheets were covered with a thin black deposit. Therefore, the outer surfaces were moistened with CHCl3 and washed with hot water after loosening. The inside of the body was then washed with 70-80 ° C with hot water until no more deposits were formed.

The casing was then connected to the circulating hot water from the thermoplastic and the temperature measured through the casing air. Since it was 49 ° C, which is insufficient, the heating element heated to 75 ° C was filled with 1300 ml to 80 ° C heated with 10% by weight. % hydrochloric acid solution with 0.2 wt. dibenzylsulfoxide CgHg.CH3-SO-CH3.CgHg and after closure placed in an inclined position on a shaker. After shaking for half an hour, the heater on the shaker was turned so that the foreheads were changed and the shaker was washed for another half hour. Then the body was removed from the shaker, the suspension was discharged to settle and filter out solids, rinsed with hot water and the thermal efficiency again measured in the same way.

The blown air temperature was 60 ° C. Finally, a solution of 1,300 ml heated to 70 ° C containing 6% by weight was poured into the heated body. of the active ingredient which was the disodium salt of ethylenediaminotetraacetic acid of the formula

NaOOC.CH, CH-COONa / ^{2 X} N-CH, -CH - N / ^{2 2 '} hooc.ch ₂ ch ₂ .cooh and washing on a shaker in the same manner as in the first operation. After thoroughly flushing the heater with hot water, the temperature of the air blown through the heater was again at 70 ° C. Since it was 67 ° C, the function of the heating cabinet was restored and the washing was terminated.

Example 2

It has been found that the heating cabinet of the same type of bus as in Example 1 is heavily clogged, poorly passable, and also heavily clogged with oil substances from the outside. The heating cabinet was therefore immersed for approximately 15 minutes in a 70 ° C warm 1% detergent solution and, after degreasing and loosening the dirt, the outer surfaces were rinsed with hot water. Washing of the interior was performed as in the first case.

After washing the inner surfaces, a third cleaning step was necessary. The 70 ° C heated heating cabinet was filled with 1300 mL of 70 ° C warm 5% wt. % oxalic acid solution HOOC.COOH with 3 wt. hydrochloric acid. After shaking the solution for one hour in a closed heating element, which was carried out as in the previous steps, the suspension was discharged to separate solids, the element was thoroughly rinsed with hot water and measured by a blown air temperature of 65 ° C .

Claims (3)

A method for cleaning heating cabinets of motor vehicles clogged with incrustations, in particular a bus housing, with a heating circuit medium consisting of a coolant circuit, characterized in that in a first stage a mixture consisting of 0.2% by weight is poured into the flow channels of the heating cabinet. the solution of a corrosion inhibitor based on amines of the formula R-NH ₂ or NH-aryl sulfoxide, RSR or ROC xanthate wherein R is alkyl or aryl, or thiourea S = C ^{r X} S.Me ^{X is} NH ₂ and, secondly, said composition consists even of 4-10% by weight. inorganic acids, e.g. hydrochloric acid HCl, optionally inorganic and carboxylic acids, e.g. acetic, in a ratio of 1: 1, followed by increments for 60 to 120 min. chemically and mechanically, for example by shaking, etching and releasing, then said mixture is discharged and the flow channels are rinsed with water until the deposits are released and then 2% to 6% by weight are poured into the flow channels of the same heating cabinet in a second stage. a solution of the amine acid salt of the formula R R ) _N-CH2-N -CHH2 Me.R R.Me ^X ^ wherein R represents acyl and release of incrustation and flow passages rinsing was repeated in the same manner as in the first stage. 2. A method according to claim 1, characterized in that from 3 to 5% by weight is poured into the flushed flow channels of the heating cabinet in a third stage. % solution of an alkanedioic acid of formula (COOR) ₂ , wherein R is H or alkyl, in an environment of 3 wt. mineral acids such as hydrochloric HCl or nitric HNO 3, whereupon the residual deposits are released and the water is flushed after the solution has been drained. Cleaning method according to Claims 1 and 2, characterized in that the washing and flushing solutions and the heating cabinet are heated to 50 ° C to 80 ° C at the beginning of each washing cycle.