JPS6117871A - Absorption refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to anti-freezing of absorption refrigerators.

Structure of a conventional example and its problems FIG. 1 shows a conventional absorption refrigerator using a water refrigerant system (in this case, water-lithium bromide). First, the absorption cycle will be briefly explained.

The dilute solution (solution containing less lithium bromide as an absorbent and more water as a refrigerant) leaving the absorber 1 is passed through a low temperature heat exchanger 3 and a high temperature heat exchanger 4 by a solution pump 2 to a high temperature regenerator 5. and a portion is sent under pressure to the low-temperature regenerator 6. In the high temperature regenerator 5, the dilute solution is heated by the burner 7 to generate refrigerant vapor. The refrigerant vapor heats the dilute solution in the low-temperature regenerator 6 using its heat of condensation and separates it into refrigerant vapor and intermediate liquid. The steam generated in the low-temperature regenerator 6 is condensed in the condenser 8, mixed with the refrigerant liquefied in the low-temperature regenerator 6, and then flows to the evaporator 9. The liquid refrigerant is circulated by the refrigerant pump 1o and is spread over the surface of the heat exchanger 12 from the dispersion pipe 11 to produce cold water using the heat of evaporation.

On the other hand, the solution concentrated in the high-temperature regenerator 6 passes through the high-temperature heat exchanger 4 and then merges with the intermediate solution heated in the low-temperature regenerator before flowing into the low-temperature heat exchanger 3. (in other words, a solution with less water refrigerant) and flows into the absorber 1 through the low-temperature heat exchanger 3. In the absorber 1, a concentrated solution is sprayed from the spray pipe 13 onto the surface of the heat exchanger 14 to absorb the vaporized steam, and the generated absorption heat is transferred to the water 2.
Cool to 0 to regenerate the dilute solution to complete the cycle. Next, freeze prevention control will be explained.

A bypass pipe 17 and a solenoid valve 18 are provided between the concentrated solution pipe 15 between the concentrated solution outlet of the low temperature heat exchanger 3 and the concentrated solution inlet of the absorber 1 and the condensate pipe 16. A sensor 197 (usually a thermostat) for detecting temperature is provided inside.

Therefore, as the temperature of the cooling water 20 decreases, the capacity of the absorber 1 increases, the absorber pressure decreases, and the evaporation temperature inevitably decreases. 18 was opened and a portion of the liquid refrigerant was mixed into the concentrated solution tube 15 or flowed into the dispersion tube 13. As a result, the amount of refrigerant per unit amount of concentrated solution flowing into the absorber 1 is increased to reduce the absorption capacity, and as a result, the decrease in absorber pressure, that is, the decrease in evaporation temperature, is suppressed.

However, such conventional anti-freeze control requires the use of sensors and solenoid valves, which has the disadvantage of increasing costs for parts and circuits, and also has the problem of high power consumption.

OBJECTS OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a control means that has a simple structure and consumes no power to prevent freezing of an absorption refrigerator.

Structure of the Invention The present invention provides a means for sensing a temperature corresponding to the evaporation temperature, which is formed of a material whose shape changes due to temperature changes, and which is directly connected to the material, and where L< is the material that flows into the absorber. This is an absorption refrigerator equipped with a control means, and this configuration prevents freezing.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows an embodiment of the present invention. Parts that are the same as in FIG. 1 are designated by the same numbers.

21 is a control valve whose details are shown in FIGS. 3 and 4. The inlet 22 of the control valve 21 is connected to the outlet of the condenser 8 or the condensate pipe 16 via a bypass pipe 24 . Further, the outlet 23 is connected to the concentrated solution tube 15 or the dispersion tube 13 through an outlet pipe 25, so that the liquid refrigerant flows into the absorber 1.

FIG. 3 shows the steady state of the control valve 21. A valve 27, a diaphragm 28, and an element 29 are installed in the main body 26, and a hole 30 is provided in the side surface.

The liquid refrigerant passes through the refrigerant pipe 16 and drips into the small hole 31 of the dispersion pipe 11, and evaporates on the surface of the heat exchanger 12, but since this saturated vapor is always in contact with the element 29, the element 2
9 can immediately sense changes in evaporation temperature. In the embodiment, the element 29 is made of a shape memory alloy and has a shape change such that it expands when the temperature is high and contracts when the temperature drops. element 29
A part of the valve 27 is fixed to the main body, and the other end is connected to the valve 27 via a diaphragm 28. Now, when the evaporation temperature decreases as the cooling water temperature decreases, the element 29 contracts as shown in FIG. 4, so that the valve 27 is lowered and the georifice 32 is opened. In this case, the condensate refrigerant mixes with the concentrated solution, and the solution becomes a partially dilute solution on the surface of the heat exchanger 14 in the absorber 1, and the absorption capacity decreases because the amount of refrigerant increases. This prevents the absorption pressure from decreasing. In this case, the amount of heat absorbed by the refrigerant absorbed into the concentrated solution before being sprayed on the cooling water can be utilized, so when hot water is used in addition to cold water, there is only a slight decrease in efficiency. When only cold water is used, the refrigerant may be allowed to flow directly into the absorber 1 without being mixed with the concentrated solution. In this case, a decrease in absorption pressure can be quickly prevented.

Although the valve 30 is directly connected to the element 29 in the embodiment, it may be formed integrally with the element 29 from the same material. The installation position of the control valve 21 does not have to be above the spray pipe 11 to provide saturated steam,
Alternatively, this position may be used as long as the temperature of a fluid such as a saturated liquid that corresponds to the evaporation temperature can be detected. Although not shown, the temperature of the so-called supercooled dilute solution after the absorption liquid reservoir 32 at the bottom of the absorber 1 is also a state quantity that is subject to fluctuations in the cooling water temperature, so it is used as a temperature corresponding to the evaporation temperature. Even if the element 29' of the control valve 21 is placed at a position where the dilute solution source can be detected, the same performance can be obtained.

In this embodiment, a shape memory alloy is used for the element 29, but a bimetal having similar properties may also be used.

Effects of the Invention As described above, the present invention senses the fluid temperature corresponding to the evaporation temperature, opens and closes the valve directly by changing the shape of the sensing element, bypasses the evaporator, and allows the refrigerant to flow into the absorber. Therefore, compared to the antifreeze control of a normal absorption refrigerator, the structure is simple, inexpensive, and has excellent effects with no power consumption.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a conventional example, Fig. 2 is a system diagram of an absorption refrigerator according to an embodiment of the present invention, Fig. 3 is a sectional view of a control valve that is a part of the present invention in a steady state, and Fig. The figure is a sectional view of the control valve when it is in operation. 1...absorber, 9...evaporator, 11.
13...Scatter tube, 15...Concentrated solution tube,
21...Control valve, 22...Inlet, 23
...Outlet, 24...Bypass pipe, 25.
...Outlet pipe, 27...Valve, 28...
...Diaphragm, 29...Element, 3o
····hole. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (3)

[Claims] (1) A means for sensing the temperature state quantity of an absorption refrigerator having at least a regenerator, a condenser, an evaporator, an absorber, and a pump is formed of a material whose shape changes with temperature changes,
and an absorption refrigerating machine comprising a control means for bypassing the evaporator and causing refrigerant to flow into the absorber through a valve directly connected to the material or formed from the material. (2) The absorption refrigerator according to claim 1, wherein the material is a shape memory alloy. (3) The absorption refrigerator according to claim 1, wherein the material is a bimetal.