JPH04363562A - Diluting device - Google Patents

Abstract

PURPOSE:To prevent a crystal accident and to shorten a diluting time at the time of stopping a refrigerator by branching a tube from a discharge side of a refrigerant or solution pump, coupling it to a concentrated solution outlet side of a regenerator, and feeding the refrigerant or dilute solution by the discharge pressure of the pump. CONSTITUTION:A forcible dilution valve 17 is provided in a forcible dilution tube 16 for connecting a discharge side of a refrigerant pump 8 to a concentrated solution tube 6a of a regenerator 1, and progress of crystal is sensed from a temperature difference of thermometers provided at the regenerator 1 and the tube 6a. If forcible dilution for preventing crystal is required, the valve 17 is opened, and the concentrated solution is diluted by regulating the valve opening time. Accordingly, its constitution is simple, small in size, its maintenance is facilitated, and a cycle efficiency can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for avoiding crystallization accidents in absorption refrigerators. The present invention also relates to a method of diluting a solution for shutting down an absorption refrigerator.

0002

BACKGROUND OF THE INVENTION In the prior art, there is no technology to detect crystals and prevent crystal accidents, and the entire cycle is set to operate at a low concentration that does not lead to crystals. Therefore, when a certain amount of refrigerant accumulates, the entire solution side becomes concentrated by that amount, and attempts are made to keep the concentration of the entire solution low by dropping the refrigerant into the solution side. However, since the danger of crystals is determined only by the amount of refrigerant, rather than by the concentrated solution system of the regenerator where there is a risk of crystals, a considerable safety margin is taken into consideration, and as a result, the amount of refrigerant charged must be increased. Design techniques were required to allow the refrigerant to cool down. In addition, even when there was no danger of crystal formation, if the refrigerant accumulated, it would fall into the solution side, resulting in a decrease in cooling capacity, making it a very inefficient method. Additionally, once crystallized, it would cause serious malfunctions and required a lot of human labor to crystallize.

[0003] In the conventional technology, with regard to dilution when the operation is stopped, the solution is naturally diluted by running the regenerator for a while after the heat input to the regenerator is eliminated, so the solution is diluted naturally. It took a while to do that.

[0004] As a known example, ``Japanese Unexamined Patent Publication No. 53-10574
3" etc.

[0005]

[Problems to be Solved by the Invention] The problems to be solved by the present invention are to directly monitor the regenerator concentrated solution system where there is a high risk of crystallization in order to avoid crystallization accidents, and to directly monitor the regenerator concentrated solution system where there is a high risk of crystallization. is to effectively dilute only the concentrated solution system where crystallization is occurring.

[0006] Furthermore, the problems to be solved by the present invention are as follows:
By directly diluting the concentrated solution system, compared to conventional technology,
The objective is to shorten the dilution time when the refrigerator is stopped.

[0007]

[Means for Solving the Problems] The present invention, as a means for sensing crystals, continuously measures the temperature of the regenerator concentrated solution outlet system where the risk of crystals is highest, and detects flow changes from the temperature changes. It is designed to detect the progress of crystals from changes in flow.

As a means to avoid crystallization accidents, the present invention branches piping from the refrigerant pump or solution pump discharge side and connects it to the regenerator concentrated solution outlet side, so that the concentrated solution in which crystallization is progressing is supplied with the pump discharge pressure. By feeding a refrigerant or dilute solution, only the concentrated solution that is beginning to crystallize is diluted.

Furthermore, in the present invention, as a means for shortening the dilution time, the amount (time) of the dilute solution or refrigerant fed is further increased (lengthened), and the diluted solution or refrigerant is caused to flow back into the regenerator.

0010

[Operation] FIG. 1 shows a diagram of the principle of the forced dilution device of the present invention.

The solution enters the regenerator 1 through the dilute solution pipe 6b, is heated and concentrated, and then exits the regenerator through the concentrated solution pipe 6a. Normally, in order to improve efficiency, the solution is heat exchanged by a heat exchanger 5 at the regenerator entrance and exit, so that the inlet side 6a is heated and the outlet side 6b is cooled. Since the solution on the exit side cooled at this time has a high concentration, the inside of the heat exchanger 5 or the exit thereof becomes the location where crystallization is most likely to occur.

When crystallization progresses in the regenerator outlet concentrated solution system, the flow of the liquid deteriorates, and as a result, the temperature difference between the regenerator temperature 18 and the exit concentrated solution system temperature 19 increases rapidly compared to during normal operation. Therefore, by monitoring the temperature difference between temperature 18 and temperature 19, it is possible to know the progress of crystallization.

If forced dilution is required to prevent crystallization, the forced dilution valve 17 is opened. When a refrigerant is used as the diluent, a refrigerant pump or the like is used as the pump 8, and when a dilute solution is used, a solution pump or the like is used as the pump 8. By pressurizing the pump 8, the diluent 16 reaches the regenerator outlet concentrated solution system 6a. Since there is a throttle 20 at the outlet of the regenerator 1 for flow rate adjustment, a portion of the diluted liquid flows toward the regenerator 1 in a reverse direction. This makes it possible to dilute the regenerator outlet concentrated solution system which is beginning to crystallize.

Furthermore, when diluting for shutting down the operation, if the forced dilution valve 17 is kept open for a long time, the refrigerant or diluted solution continues to flow into the regenerator and the concentrated solution in the regenerator 1 turns into a low concentration liquid. It can be diluted in a short time by mixing with

[0015]

[Embodiment] An embodiment of the present invention will be described below. FIG. 2 shows an example in which a forced dilution device using a refrigerant is incorporated into a dual-effect absorption refrigerator.

[0016] The double-effect absorption refrigerator has regenerators 1, 1a,
Consisting of a condenser 2, an evaporator 3, an absorber 4, pumps 8, 8a that circulate absorption liquid 6, 6a, 6b, 6c and a refrigerant 7 between these, and heat exchangers 5, 5a, each part is Each operates as follows.

(A) Evaporator 3 Chilled water 10 flows into the tubes of the evaporator tube bundle 9 of the evaporator 3, and the refrigerant 7 supplied from the refrigerant pump 8b is sprayed from the spray nozzle 11 outside the tubes. Heat is removed from cold water by latent heat of vaporization.

(B) Absorber 4 Lithium bromide aqueous solution has a significantly lower vapor pressure than water at the same temperature, and can absorb water vapor generated at considerably lower temperatures. In the absorber 4, the refrigerant vapor evaporated in the evaporator 3 is
It is absorbed by the lithium bromide aqueous solution (absorption liquid) 6 sprinkled on the outer surface of the cooling pipe 12 of the absorber 4, and the absorbed heat generated at this time is cooled by the cooling water 13 passing through the pipe.

(C) Regenerators 1 and 1a Dilute absorption liquid 6b whose concentration has decreased by absorbing refrigerant in the absorber 4
has a weaker absorption capacity. Then, a part of the solution is sent to the high-temperature regenerator 1 by the solution circulation pump 8a and heated by a gas burner or the like, and the high-temperature refrigerant vapor 14 is evaporated and separated, the solution is concentrated, and the concentrated solution 6a is returned to the absorber 4. Further, a part of the dilute absorption liquid 6b discharged from the absorber is sent to the low temperature regenerator 1a by the solution circulation pump 8a, where it is heated and concentrated by the high temperature refrigerant vapor 14 generated in the high temperature regenerator 1, and the solution 6c is transferred to the heat exchanger 5.
The concentrated absorption liquid 6 is mixed with the absorption liquid 6a discharged from the high-temperature regenerator and returned to the absorber 4.

(D) Condenser 2 The high-temperature refrigerant vapor 14 separated in the high-temperature regenerator 1 releases part of its heat in the low-temperature regenerator 1a and enters the condenser 2, where it passes through the inside of the cooling pipe 15. It is cooled by the flowing cooling water 13, condenses and liquefies, and returns to the steamer 3 as a refrigerant 7a.

(E) Heat exchangers 5, 5a Transfer the low-temperature dilute absorption liquid 6b from the absorber 4 to the high-temperature regenerator 1 and low-temperature regenerator 1a to the high-temperature regenerator 1 and from the low-temperature regenerator 1a to the absorber 4. preheated with concentrated solutions 6a, 6c of
Increase thermal efficiency.

(F) Pumps 8a, 8b The solution circulation pump 8a circulates an aqueous lithium bromide solution (absorbing liquid), and the refrigerant pump 8b circulates a refrigerant (water).

(G)-1 Forced dilution device The forced dilution device of the present invention has a forced dilution pipe 16 that connects the refrigerant 7 on the discharge side of the refrigerant pump 8b and the outlet concentrated solution system 6a of the regenerator 1.
and a forced dilution valve 17 provided in the middle. Regarding the prevention of crystallization accidents, attention is paid to the temperature 18 of the regenerator 1 and the temperature 19 of the concentrated solution 6a at its outlet. When crystals begin to develop in the concentrated solution 6a, the viscosity of the concentrated solution 6a increases and the amount of circulation thereof decreases. Then, since the high temperature solution from the regenerator 1 is no longer supplied, the temperature 19 drops rapidly. Therefore, when the difference between temperature 18 and temperature 19 exceeds a set value, it is determined that the risk of crystal formation is large and the forced dilution valve is opened. Then, the refrigerant pushed out by the refrigerant pump 8b passes through the forced dilution pipe 16 and is supplied to the regenerator outlet section 6a. Since there is a throttle 20 at the regenerator outlet 6b for flow rate adjustment, a part of the refrigerant sent passes through the throttle 20 and pushes out the concentrated solution into the absorber 4, and a part flows back into the regenerator 1. flows into. When the forced dilution solenoid valve 17 is closed immediately after this backward flowing refrigerant reaches the regenerator 1, the concentrated solution at the regenerator outlet 6a, which was about to cause crystals, is replaced with refrigerant liquid, and the crystals at the regenerator outlet are replaced. is crystallized.

At the time of dilution when the operation is stopped, by opening the forced dilution valve 17, the refrigerant 7 is supplied to the forced dilution pipe 16 in the same manner as above.
is supplied to the regenerator outlet 6a, and a part of it is supplied to the regenerator 1
sent inside. Therefore, the inside of the regenerator is diluted and the pressure increases due to the characteristics of the solution. Therefore, when the forced dilution solenoid valve 17 is closed, the pressure inside the regenerator is high, so the flow (circulation) of the solution returning from the regenerator to the absorber becomes smooth. Therefore, by repeating this once or several times, the inside of the regenerator can be diluted within a short time.

FIG. 3 shows an example in which a forced dilution device using a dilute solution is incorporated into a dual-effect absorption refrigerator similar to the one described above. The operation is the same except that the refrigerant in the above explanation is replaced with a dilute solution.

[0026]

[Effects of the Invention] According to the forced dilution device of the present invention, crystallization to prevent crystallization accidents and dilution during shutdown can be easily performed with one device by simply changing the time period during which the forced dilution solenoid valve is open. and can be done effectively.

The configuration of the present invention is extremely simple,
It can be realized inexpensively.

By using the forced dilution device of the present invention, an interlock method for preventing crystallization can be established, so that operational safety can be improved and serious failures can be avoided. This allows the solution cycle of the absorption refrigerator to be shifted to the high concentration side, making it possible to increase cycle efficiency and downsize the machine.

According to the crystallization method using the forced dilution device of the present invention, the refrigeration cycle is not significantly damaged, so crystallization accidents can be avoided without significantly affecting the cooling capacity.

By measuring the number of operations and the frequency of operation of the forced dilution device of the present invention, maintenance can be performed before a serious accident (stoppage due to an accident) occurs.

By automatically transmitting the number of operations and the frequency of operation of the forced dilution device of the present invention to a central monitoring room, a manufacturer's service center, etc., it becomes easy to grasp the operating status of the refrigerator.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of a forced dilution device according to the present invention.

FIG. 2 is a cycle flow diagram of an embodiment in which a forced dilution device is incorporated into a dual-effect absorption refrigerator.

FIG. 3 is a cycle flow diagram of an embodiment in which a forced dilution device is incorporated into a dual-effect absorption refrigerator.

[Explanation of symbols]

1... (high temperature) regenerator, 1a... low temperature regenerator, 2... condenser,
3...Evaporator, 4...Absorber, 5,5a...Heat exchanger, 6...Absorber inlet concentrated solution, 6a...Regenerator outlet concentrated solution, 6b...Absorber outlet dilute solution, 6c...Low temperature regenerator outlet dilute solution , 7... Refrigerant, 8... Pump, 8a... Solution pump, 8b... Refrigerant pump,
9... Evaporator tube bundle, 10... Chilled water, 11... Refrigerant spray nozzle, 12... Absorber cooling pipe, 13... Cooling water, 14... Refrigerant vapor, 15... Cooling pipe, 16... Forced dilution piping, 17... Forced dilution valve, 18...Regenerator temperature, 19...Regenerator outlet system temperature.

Claims (3)

[Claims] Claim 1: In an absorption refrigerating machine, in order to prevent crystallization accidents or for dilution when the operation is stopped, the refrigerant is branched from the refrigerant pump discharge side piping, and the pump discharge pressure is used to transfer the refrigerant to the regenerator concentrated solution outlet system. A diluting device that is characterized by feeding into [Claim 2] In an absorption refrigerator, in order to prevent crystallization accidents or for dilution when the operation is stopped, the dilute solution is branched from the solution pump discharge side piping and is transferred to the regenerator concentrated solution outlet using the pump discharge pressure. A dilution device that is characterized by feeding into the system. 3. In an absorption refrigerator having the dilution device according to claim 1 or 2, danger of crystallization is detected by measuring the temperature of the regenerator outlet concentrated solution system, and a crystallization prevention function is activated. A crystal accident prevention method characterized by: