JPS61223459A - Method of controlling solution pump for 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 Application Field] The present invention is directed to a double-effect absorption refrigerator (including an absorption chiller/heater).
The present invention relates to a control method for controlling starting and stopping of a solution pump.

[Conventional technology]

A conventional dual-effect absorption refrigerator, for example, as shown in FIG. A pump RP is provided, and as a solution path, 2
1.22.23.24.25.26.27, 1O11112, 13 as a refrigerant path, and an overflow pipe 20 connect the above-mentioned devices to form a refrigeration cycle. In addition, 1 is a cold water pipe, 2.3 is a cooling water pipe, 4 is a heat source supply pipe, 5 is a cold water thermometer, 6 is a temperature regulator, H is a heat source control valve, 30.
31 is an electrode rod of a level switch for starting and stopping the solution pump.

In such a refrigeration cycle, at the start of operation, the pressure in the high temperature generator GH is low and the circulation of the solution from the high temperature generator GH to the low temperature generator GL is poor, so the solution accumulates in the high temperature generator GH and absorber A Cavitation may occur in the solution pump SP due to insufficient solution volume in the high temperature generator GH.
There was a risk that the solution inside would mix into the refrigerant side. Therefore, a level switch for starting and stopping the solution pump 182, for example, two electrode rods 30 and 31, is attached to the high temperature generator GH, and when the solution level rises to one of the upper limit electrode rods 30 and comes into contact, the solution pump SP is stopped, the liquid level is lowered to below the level of the other lower limit electrode rod 31,
The solution pump SP was restarted when electrical continuity with the electrode rod 31 was lost.

Fig. 2 shows an example of a level switch for starting and stopping the solution pump installed at the appropriate location of the high temperature generator GH. It is attached to the casing via a gasket 32. The electrode rod 31 is for detecting the lower liquid level (for restarting) and is attached to the casing via an insulating airtight packing 32.

Figure 3 shows a sequence circuit, in which 883P is an electromagnetic switch for the solution pump, El is turned on when the electrode rod 30 is electrically connected to the liquid surface, and E2 is turned on when the electrode rod 31 is electrically connected to the liquid surface. This is the switch.

[Problem that the invention seeks to solve]

However, in a device using such a conventional level switch for starting and stopping the solution and pump, two electrodes, the upper liquid level detection electrode 30 (for stopping) and the lower liquid level detection electrode 31 (for restarting), are used. I am using book electrodes, and these electrodes are 30
, 31 are attached to the casing via a packing 32. However, if a leak occurs in the sealing part or the attachment part of the packing 32 during use, the high temperature generator GH will cause a problem with vacuum sealing, and the absorption refrigeration There was a problem in that it seriously affected the performance of the machine.

An object of the present invention is to provide a solution pump control method for an absorption refrigerating machine that can reduce the vacuum-tightness problem of the conventional level switch for starting and stopping the solution pump and can continue stable operation for a long period of time. It is something.

That is, when the solution pump stops, ψ inside the high temperature generator
Focusing on the fact that the rate of drop in the liquid level is almost constant when the absorption refrigerator is in steady operation, the electrode rod 31 for restarting the solution pump is omitted to reduce the leakage factor by half. .

[Means for solving problems]

The present invention, as a means for solving the above problems,
It has an absorber, a high temperature generator, a low temperature generator, a condenser, an evaporator, a solution heat exchanger, a solution pump, a refrigerant pump, and a solution path and refrigerant path that connect these devices, and provides a heat source to the high temperature generator. In the solution pump control method for an absorption refrigerator that supplies liquid to form a refrigeration cycle, after detecting the solution pump stop liquid level of the high temperature generator and stopping the solution pump, after a predetermined time elapses, the solution pump The present invention provides a solution pump control method for an absorption refrigerator, characterized in that the solution pump is restarted.

[Effect]

When the solution pump stop liquid level switch attached to the high temperature generator detects the upper liquid level and stops the solution pump, the stop liquid level in the generator falls at a substantially constant rate of decline during steady operation.

Focusing on the fact that the time required for the solution pump to reach the restarting liquid level is also approximately constant, this is set, for example, by a timer, and the solution pump is restarted by this timer. Further, it is also possible to focus on the fact that the liquid level lowering speed changes depending on the pressure inside the high temperature generator, to detect this pressure, and to change the set time of the timer according to the detected value. At this time, the pressure inside the high temperature generator is not directly controlled.
It is also possible to indirectly detect other state quantities that have a correlation with this, such as the refrigerant condensation temperature of the high temperature generator, and change the set time according to the detected value.

〔Example〕 Embodiments of the present invention will be described using the drawings.

In FIG. 4, parts with the same reference numerals as in FIG. 1 have the same structure and function as in FIG. 1.

In the high temperature generator GH, an electrode rod 30 as shown in FIG. 2 is attached to the casing via a packing 32 as a level switch for stopping the solution pump SP. This level switch may be of a float type. A pressure sensor 35 is provided above the high temperature generator GH, and a temperature sensor 36 is provided in the refrigerant pipe of the low temperature generator GL.

37 is a controller that includes a timer 38 and controls the start and stop of the solution pump SP according to the signal from the electrode rod 30; 39 is a controller that controls the set value of the timer 38 according to the signal from the pressure sensor 35 and/or the temperature sensor 36; This is a setting device to change.

FIG. 5 is a sequence diagram of this embodiment. sEl is a switch that is turned on when there is continuity between the electrode rod 30 of the level switch and the liquid surface, and turned off when there is no continuity.

In operation, when the solution level in the high temperature generator GH rises and reaches the electrode rod 30, El closes and the solution pump SP
stops. At that point, timer T (timer 38) starts, and at the same time the liquid level begins to fall. After a predetermined period of time has elapsed, the timer T is activated, the solution pump SP is restarted, and the operation is continued by repeating this process.

In FIG. 6, a timer T which operates in about 2 to 5 seconds is used in place of the auxiliary relay RY shown in FIG. 5, and it is possible to prevent fluttering due to undulation of the solution.

FIG. 7 shows that when the pressure inside the high temperature generator GH changes,
When changing the setting time of the timer T according to the pressure, the predetermined time for restarting the solution pump SP (
The pressure of the high temperature generator GH is measured by the pressure sensor 35, and the condensation temperature of the refrigerant vapor of the high temperature generator GH is measured by the temperature sensor 3.
6, and the signals are selectively processed by a setter 39, and the set time of the timer T (timer 38) is adjusted.

Since the rate of drop of the liquid level changes depending on the pressure, by adjusting the set time in this way, even if the pressure changes, control can be performed that approximately corresponds to the actual amount of drop of the liquid level.

If the change in pressure is not very large, the timer can be set constant without using a pressure or temperature signal.

〔Effect of the invention〕

The present invention reduces the number of level switch installations from the conventional two locations to one location, halves the factors that cause airtightness problems, improves reliability, and provides an absorption refrigerator with an extremely simple structure. A solution pump control method can be provided.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram of a conventional example, FIG. 2 is a cross-sectional explanatory diagram of a detection level switch of a conventional example, FIG. 3 is a pump control sequence diagram of a conventional example, and FIG. 4 is a flow diagram of an embodiment of the present invention. FIG. 5 is a sequence diagram thereof, FIG. 6 is a sequence diagram of another embodiment of the present invention, and FIG. 7 is a graph showing the relationship between pressure and predetermined time in the embodiment of the present invention. l...Cold water pipe, 2.3...Cooling water pipe, 4...Heat source supply pipe, 5...Cold water thermometer, 6...Temperature controller, 1
0,11°12.13... Refrigerant path, 20... Overflow pipe, 21.22, 23.24, 25, 26.
27...Solution route, 30.31...Electrode rod, 32.
...Packing, 35...Pressure sensor, 36...Temperature sensor, 37...Controller, 38...Timer, 39
...Setting device.

Claims (1)

[Claims] 1. An absorber, a high temperature generator, a low temperature generator, a condenser, an evaporator, a solution heat exchanger, a solution pump, a refrigerant pump, and a solution path and a refrigerant path that connect these devices. In the solution pump control method for an absorption refrigerator that supplies a heat source to a high temperature generator to form a refrigeration cycle, after detecting a solution pump stop liquid level of the high temperature generator and stopping the solution pump, a predetermined A solution pump control method for an absorption refrigerator, characterized in that the solution pump is restarted after a period of time has elapsed. 2. The method according to claim 1, wherein the predetermined time is determined by directly or indirectly detecting the pressure within the high temperature generator and changing the predetermined time according to the detected value.