JPH0233581A - Absorption type refrigerating machine - Google Patents

Abstract

PURPOSE:To discharge non-condensed gas without deteriorating the absorbing rate of absorbing solution by a method wherein the saturating vapor pressure of heat medium is compared with a pressure in an evaporator by an operator and when the pressure in the evaporator is higher than a predetermined value, an air discharging pump is driven to discharge the non-condensed gas in the evaporator or an absorber. CONSTITUTION:When non-condensed gas exists in an evaporator 1 or an absorber 5 and the absorbing rate of absorbing solution is deteriorated, a pressure in the evaporator 1 becomes a saturated water vapor pressure, corresponding to the evaporating temperature of water, added with the pressure of the non-condensed gas. The pressure in the evaporator 1 is compared with the saturated water vapor pressure, corresponding to the evaporating temperature of water, by an operator and when a difference is larger than a predetermined value, a vacuum pump 24 is driven to suck the water vapor containing the non-condensed gas. When a pressure in another chamber 34c in a diaphragm actuator 34 becomes higher than a chamber 34b communicated with a temperature sensitive tube 31, a piston 34d is operated through the diaphragm 34a to put a relay switch 34 ON, drive the vacuum pump 24 and suck the water vapor containing the non-condensed gas in the evaporator 1 to discharge it.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an absorption refrigerator capable of preventing the precipitation of crystals in an absorption liquid.

Conventional technology Absorption refrigerators consist of an evaporator that evaporates the heat medium, an absorber that absorbs the heat medium vapor generated in the evaporator into an absorbing liquid, and a refrigeration system that absorbs the heat medium vapor to reduce its concentration. It is equipped with a regenerator that heats the absorption liquid and a condenser that condenses the heat medium vapor obtained by the regenerator. The absorption liquid contains, for example, L.
An iBr (lithium bromide) aqueous solution is used, and this absorption liquid is operated at a high concentration of about 60%.

Problem to be Solved by the Invention By the way, especially when starting up this absorption chiller, if non-condensable gas is present in the chiller, this non-condensable gas will inhibit the absorption phenomenon of heat medium vapor (water vapor) in the absorber. do. As a result, the absorption liquid is only concentrated in the regenerator, and the concentration of the absorption liquid becomes high, which causes crystals to precipitate in the absorption liquid. If these crystals are deposited in the absorption liquid transfer pipe between the absorber and the regenerator, they will obstruct the flow of the absorption liquid and reduce the capacity of the refrigerator.Crystallization work is required to remove these crystals. did.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an absorption refrigerator that can discharge non-condensable gas from inside the refrigerator so that the absorption rate of the absorption liquid does not decrease.

Means for Solving the Problems In order to solve the above problems, the first means of the present invention is to provide a temperature detection device for detecting the temperature of the heat medium in the evaporator, and a pressure detection device for detecting the pressure in the evaporator. a device, and the detection values of the temperature detection device and the pressure detection device are input, and the pressure value in the evaporator is compared with the saturated vapor pressure of the heat medium corresponding to the temperature of the heat medium, and an operation is performed to start the exhaust pump. The exhaust pump is connected to at least an evaporator or an absorber to discharge non-condensable gas from the evaporator or absorber.

Further, the second means includes a diaphragm actuator that is connected to a gas phase part of a heat medium liquid phase intermediate vessel of the evaporator, and a diaphragm of the diaphragm actuator is configured to direct the non-condensable gas in the evaporator to at least the evaporator or the evaporator. This is interlocked with the switch of the exhaust pump that discharges air from the absorber.

In the first method, if there is a large amount of non-condensable gas in the evaporator or absorber, the pressure in the evaporator increases by adding the non-condensable gas pressure to the saturated vapor pressure of the heating medium. do. Therefore, the calculator compares the saturated vapor pressure of the heat medium calculated based on the input temperature of the heat medium with the pressure inside the evaporator, and determines that the pressure inside the evaporator is higher than the saturated vapor pressure by a predetermined value. When this occurs, the exhaust pump is driven to discharge at least the non-condensable gas in the evaporator or absorber, thereby preventing a decrease in the absorption rate of the absorbent in the absorber and preventing an increase in the concentration of the absorbent. It is possible to prevent crystal precipitation of the absorption liquid.

In addition, according to the second means, the pressure difference between the saturated vapor pressure of the heat medium caused by the temperature sensing cylinder t introduced into one chamber of the diaphragm actuator and the pressure inside the evaporator introduced into another chamber is detected by the diaphragm actuator. A switch linked to the diaphragm starts the exhaust pump to exhaust at least the non-condensable gas in the evaporator or absorber, thereby preventing a decrease in the absorption rate of the absorbent in the absorber and increasing the concentration of the absorbent. It is possible to prevent the precipitation of crystals in the absorption liquid.

EXAMPLE Hereinafter, a first example of the present invention will be described based on a schematic diagram showing the general structure of an absorption refrigerator shown in FIG.

The absorption refrigerator in the first embodiment includes an evaporator 1 that evaporates water, which is an example of a heat medium, and a system that conducts (and absorbs) the water vapor generated in the evaporator 1 through a communication section 2. An absorber 3 containing a lithium bromide (LiBr) aqueous solution (hereinafter referred to as absorption liquid), a regenerator 4 that heats the diluted absorption liquid that absorbs water vapor, and is heated by the regenerator 4. The water vapor generated by this is transferred to the communication section 5.
A condenser 6 that condenses the water vapor while guiding it through the water vapor.
, a dilute absorption liquid transfer pipe 8 which has a solution tube 7 on the way and which transfers the dilute absorption liquid in the absorber 3 to the regenerator 4; The condensed water transfer pipe 9 has a heat medium pump 10 in the middle, and the condensed water, which is a heat medium accumulated at the bottom of the condenser 6, is transferred into the condenser 6 through a part of the condensed water transfer pipe 9. a condensed water circulation pipe U that circulates the condensed water to the regenerator 4, and a concentrated absorption liquid transfer w1 that transfers the concentrated absorption liquid that has become concentrated after steam separation in the regenerator 4 to the absorber 3.
2, a first heat exchanger 13 for cooling a fluid to be cooled, such as water, arranged in the evaporator 1, and a second heat exchanger 14 for internal cooling arranged in the absorber 3. , a cooling fluid piping 15 for guiding water, which is a cooling fluid, to the first heat exchanger 13, and a cooling fluid piping 15, for guiding water, which is a cooling fluid, to the second heat exchanger 14. The outlet side portion of this cooling fluid piping is guided into the condenser 6 to take away the heat of condensation. A heat recovery device 18 is provided between the concentrated absorption liquid transfer pipe 12 and the dilute absorption liquid transfer pipe 8 to recover the heat of the concentrated absorption liquid to the dilute absorption liquid side.

The evaporator 1 is provided with a temperature detection device 21 that measures the temperature of water (evaporation temperature) as a heat medium, and a pressure detection device 22 that measures the pressure inside the evaporator 1. The detected values of the device 21 and the pressure detection device 22 are input to the calculator 23. Further, in the evaporator 1, a vacuum pump 24 that sucks and discharges vapor containing non-condensable gas is connected to a degassing pipe 25.
The vacuum pump 24 is driven by a drive device 24a. The computing unit 23 calculates the saturated water vapor pressure corresponding to the input evaporation temperature, compares the saturated water vapor pressure with the pressure of the evaporator 1, and determines whether the pressure of the evaporator 1 is ITorr or more than the saturated water vapor pressure. It is configured to output a start signal to the drive device 24a to start the vacuum pump 24 when the vacuum pump 24 is reached. Alternatively, an alarm signal may be issued to notify the operator and the vacuum pump 24 may be started manually.

In the above configuration, if there is a large amount of non-condensable gas in the evaporator 1 and the absorber 3, which may reduce the absorption rate of the absorption liquid in the absorber 3, the pressure in the evaporator 1 will decrease. The pressure of the non-condensable gas is added to the saturated water vapor pressure corresponding to the evaporation temperature of water in the vessel 1. Therefore, the calculator 23 compares the pressure inside the evaporator 1 with the saturated water vapor pressure corresponding to the evaporation temperature of water, and when the pressure in the evaporator 1 is equal to or higher than a predetermined value (for example, ITorr), the vacuum pump 24 is activated to vaporize water containing noncondensable gas. , it is possible to reduce the amount of non-condensable gas in the evaporator 1 and absorber 3, to prevent a decrease in the absorption of the absorption liquid, and to prevent the precipitation of crystals without increasing the concentration of the absorption liquid.

Note that the degassing pipe 25 may be connected to the absorber 3.

A second embodiment will be described based on FIG. 2. The same members as those in the first embodiment are given the same reference numerals, and explanations thereof will be omitted.

In the heat medium liquid phase (water) inside the evaporator 1, a temperature sensitive tube 31 filled with water, which is the same heat medium, is disposed.
The saturated water vapor pressure corresponding to the temperature (evaporation temperature) of the water inside is taken out by the thin tube 32.

This thin tube 32 and a pressure conduit 33 communicating with the gas phase portion of the evaporator 1 are connected to a diaphragm actuator 34, respectively. That is, one chamber 34 partitioned by the diaphragm 34a within the diaphragm actuator 34
A thin tube 32 is connected to b, and a pressure conduit 33 is connected to the other chamber 34C. And diaphragm 34
A spindle 34d connected to the chamber 3ib is protruded outward from the chamber 3ib side, and a contact piece 35 of the relay switch 35 of the vacuum pump 24 is attached to the tip of the spindle 34d.
a are linked together. A spring 34e for adjusting the operating pressure is disposed on the spindle 34d of the diaphragm actuator 34, and the spindle 34d is set to be operated when the pressure on the other chamber 34C side from the -chamber 34b side becomes ITorr or more, The relay switch A is turned on and the drive device 24a is configured to start the vacuum pump.

In the above configuration, if there is a large amount of condensed gas in the evaporator 1 and the absorber 3, and there is a possibility that the absorption rate of the absorption liquid in the absorber 3 will decrease, the pressure in the evaporator 1 will be lower than that of the evaporator. The pressure of the non-condensable gas is added to the saturated water vapor pressure corresponding to the evaporation temperature of water in 1. Therefore, the pressure in the other chamber 34C in the diaphragm actuator 34 is higher than that in the chamber 34b communicating with the temperature sensing tube 31.
The spindle 34d is actuated via the diaphragm 34a, turning on the relay switch A and turning on the vacuum pump 24.
to drive. Then, water vapor containing non-condensable gases is sucked and discharged in the evaporator 1 to prevent a decrease in the absorption rate of the absorption liquid, prevent an increase in the concentration of the absorption liquid, and prevent the precipitation of crystals in the absorption liquid.

In addition, in the said 2nd Example, the said degassing pipe may be connected to an absorption chamber.

Effects of the Invention As described above, according to the first means of the present invention, when there is a large amount of noncondensable gas in the evaporator or absorber, the pressure in the evaporator is reduced to the saturated vapor pressure of the heat medium. It becomes the added non-condensable gas pressure and rises. Therefore, the calculator compares the saturated vapor pressure of the heat medium calculated based on the input temperature of the heat medium with the pressure inside the evaporator, and determines that the pressure inside the evaporator is higher than the saturated vapor pressure by a predetermined value. When this occurs, the exhaust pump is driven to discharge at least the non-condensable gas in the evaporator or absorber, thereby preventing a decrease in the absorption rate of the absorbent in the absorber and preventing an increase in the concentration of the absorbent. It is possible to prevent crystal precipitation of the absorption liquid.

According to the second means, the pressure difference between the saturated vapor pressure of the heat medium caused by the temperature sensing tube introduced into one chamber of the diaphragm actuator and the pressure inside the evaporator introduced into the other chamber is controlled by the diaphragm. The exhaust pump is activated by a switch linked to the diaphragm to exhaust at least the non-condensable gas in the evaporator or absorber, thereby preventing the absorption rate of the absorbent from decreasing in the absorber and increasing the concentration of the absorbent. It is possible to prevent the precipitation of crystals in the absorption liquid.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the general structure of an absorption refrigerating machine according to the first embodiment of the present invention, and FIG. 2 is a schematic diagram showing the schematic structure of the absorption refrigerating machine according to the second embodiment. 1... Evaporator, 3... Absorber, 4... Regenerator, 6
... Condenser, 21 ... Temperature detection device, 22 ... Pressure detection device, 23 ... Arithmetic unit, 24 ... Vacuum pump, 24a ... Drive device, 25 ... Degassing pipe, 31...
・Thermosensing tube, 32... Thin tube, 33... Pressure conduit, 34
...Diaphragm actuator, 34a...Diaphragm, 34b...-chamber, 34c...Other chamber, 35
...Relay switch.

Claims (1)

[Claims] 1. A temperature detection device for detecting the temperature of the heat medium in the evaporator and a pressure detection device for detecting the pressure in the evaporator are provided, and the detected values of the temperature detection device and the pressure detection device are provided. is input and compares the pressure value in the evaporator with the saturated vapor pressure of the heating medium corresponding to the temperature of the heating medium, and starts the exhaust pump, and the exhaust pump is connected to at least the evaporator or the absorber. An absorption refrigerating machine characterized in that it is configured to be connected to discharge non-condensable gas from an evaporator or an absorber. 2. A temperature-sensitive cylinder filled with the same heat medium as that of the evaporator is provided in the heat-medium liquid phase part of the evaporator, and one chamber partitioned by a diaphragm is communicated with the temperature-sensing cylinder, and another chamber is connected to the temperature-sensing cylinder. A diaphragm actuator communicated with the gas phase portion of the evaporator is provided, and the diaphragm of the diaphragm actuator is operatively connected to a switch of an exhaust pump that discharges non-condensable gas in the evaporator from at least the evaporator or absorber. Features of absorption refrigerator.