JPH06201211A - Liquid level control method for absorptive refrigeration machine - Google Patents

Abstract

PURPOSE:To control a number of revolutions of an absorbing liquid pump by measuring a liquid level of an absorbing liquid in a high temperature regenerator and facilitate the maintenance by reducing a number of on/off operations for prolongation a service life of the pump and making a liquid level measuring instrument resistant to dirt. CONSTITUTION:Provided in a liquid detection box 25, which is provided in communication with an interior of a high temperature regenerator 1, is a magnetostrictive level gauge 30 having a magnetostrictive wire 31, a reference magnet 32 and a float magnet 33. A liquid level 28 of an absorbing liquid 27, on which the float magnet 33 floats, is found by finding a distance between the reference magnet 32 and the float magnet 33, so that a control signal corresponding to the liquid level is output to an absorbing liquid pump 16 from a control 41 which then controls a number of revolutions of the pump to regulate an absorbing liquid level in the high temperature regenerator 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the amount of liquid absorbed in a high temperature regenerator of an absorption refrigerator, specifically, the liquid level.

[0002]

2. Description of the Related Art As a technique of this kind, a device using a plurality of electrode rods as shown in FIG. 4 is proposed in Japanese Patent Publication No. 60-22255.

In FIG. 4, reference numeral 1 denotes a high temperature regenerator having a combustion heating chamber 2 for gas or oil and a plurality of exhaust heat pipes 3 connected to the heating chamber to heat and separate a refrigerant from a dilute liquid (direct heating type). Reference numeral 4 is a low temperature regenerator for further heating and separating the refrigerant of the intermediate liquid by using the refrigerant vapor sent out from the high temperature regenerator as a heat source, and 5 is condensed by the cooler 6 the refrigerant flowing from the regenerators 1 and 4, And a condenser for cooling, 7 is an evaporator for spraying the refrigerant liquid from the condenser 5 and utilizing the latent heat of vaporization to obtain cold water for cooling from the water cooler 8,
Numeral 9 sprays the concentrated liquid from which the refrigerant has been separated by the low temperature generator 4 to absorb the refrigerant vapor in the container, thereby maintaining the inside of the evaporator 7 at a low pressure and continuously supplying cold water. The absorbers 10, 10 and 11 are a low temperature heat exchanger and a high temperature heat exchanger, which are the refrigerant conduit 12 and the refrigerant liquid flow-down pipe 1.
3, the refrigerant circulation path 15 having the refrigerant pump 14, the dilute liquid pipes 17, 18 and 19 having the absorbing liquid pump 16, the intermediate liquid pipes 20 and 21, and the concentrated liquid pipes 22 and 23 are connected to form a refrigeration cycle. Reference numeral 24 is a water heater attached to the high temperature regenerator 1.

Then, four electrode rods (A, B, C, D) of different lengths are installed in the liquid level detection box 25 provided in communication with the inside of the high temperature regenerator 1, and the position of the electrode rod D is set. When the liquid level 28 of the absorbing liquid 27 comes to the electrode, a current flows through the electrode rod D to disconnect the relay contact 26, stop the operation of the absorbing liquid pump 16, and lower the liquid level 28 to the position of the electrode rod C for restoration. Then, the operation of the absorption liquid pump 16 is restarted, and when the liquid level 28 drops to the position of the electrode rod B for minimum liquid level detection, the amount of the absorption liquid 27 of the high temperature regenerator 1 is small, so the temperature is Since there is a danger of a sudden rise, the absorption chiller is designed to be stopped in an emergency. The electrode rod A is an electrode rod for grounding.

However, in the apparatus having the above-described structure, since the control is performed such that the liquid level 28 of the absorbing liquid 27 is detected and the operation of the absorbing liquid pump 16 is simply turned on / off, the number of times of turning on / off increases and the absorbing liquid The pump 16 deteriorates early and its life is short. Since the liquid level 28 of the absorbing liquid 27 cannot be taken out as a linear signal, the absorbing liquid 2 by the absorbing liquid pump 16
The circulation amount control of No. 7 cannot be performed, and the performance during partial load operation is poor. Due to the large number of electrode rods, there are many mechanical failures such as air leaking from the installation location of the electrode rod / liquid level detection box. Since a voltage is applied between the electrode rod and the ground electrode rod to cause a current to flow in the absorbing liquid 27, there are many problems that the electrode rod and the device may be corroded.

As a technique for solving the problem in Japanese Patent Publication No. 60-22255, a liquid surface 28 of the absorbing liquid 27 is disclosed.
As a technique for controlling the number of revolutions of the absorbing liquid pump by detecting the electrostatic capacitance type liquid level gauge, as shown in FIG.
There is a publication of 3365.

According to the technique disclosed in Japanese Unexamined Patent Publication No. 4-283365, a capacitance type liquid level gauge 29 is attached to a liquid level detection box 25 attached to the high temperature regenerator 1, and this liquid level gauge measures the liquid level of the absorbing liquid 27. Since the rotation speed of the absorption liquid pump 16 is controlled according to the value measured and output on the surface 28, the number of times the absorption liquid pump 16 is turned on / off is reduced, and deterioration of the absorption liquid pump 16 can be prevented. Since the level of the liquid surface 28 can be taken out as a linear signal, it is possible to control the circulation amount of the absorption liquid 27 by the absorption liquid pump 16, and the performance during partial load operation is improved. Since it suffices to install one level gauge instead of a large number of electrode rods, mechanical failure such as air leaking from the installation section is reduced. Further, since no current is passed through the absorbing liquid 27, there are many advantages such as no danger of corrosion.

[0008]

However, in the absorption type refrigerator using the capacitance type liquid level gauge, when the liquid level gauge is contaminated by the absorbing liquid, the liquid level is actually lowered and absorbed. Even if the liquid is low, the capacitance is measured larger than it actually is, so there is a problem that the liquid surface shifts to the higher side as it is used for a long time, and it is resistant to dirt and maintenance. It was hoped that the development of a simple absorption refrigerator would be possible.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, in which a high temperature regenerator, a low temperature regenerator, a condenser, an evaporator, an absorber, a heat exchanger, etc. are installed in a pipe. In an absorption refrigerator that constitutes a refrigeration cycle by connecting, a wall surface of the high temperature regenerator is provided with a liquid level detection box that is in communication with the inside of the high temperature regenerator and through which both the absorbing liquid and the refrigerant vapor can flow in and out, A magnetostrictive liquid level meter having a magnetostrictive wire, a reference magnet, and a float magnet is installed in this liquid level detection box, and the float magnet floats by obtaining the distance between the reference magnet and the float magnet of this magnetostrictive liquid level meter. The liquid level of the high temperature regenerator is controlled by controlling the number of revolutions of the absorption liquid pump installed between the absorber and the high temperature regenerator based on the detected liquid level. control A liquid level control method for an absorption refrigerator according to claim Rukoto,

The temperature sensor for detecting the temperature of the absorbing liquid is installed in the liquid level detection box, and the output of the magnetostrictive liquid level gauge is temperature-corrected according to the output value of the temperature sensor. And a liquid level control method for an absorption refrigerator,
This is to solve the above-mentioned problems of the conventional technology.

[0011]

[Operation] When a pulse current flows through the magnetostrictive wire, when the pulse current flows through the reference magnet and the float magnet side, an instantaneous force acts on the magnetostrictive wire at each position to cause twisting. Propagate inside the magnetostrictive wire at the speed of sound. Therefore, the separation distance between the reference magnet and the float magnet is measured by measuring the arrival time difference of the twisting phenomenon that occurs at the positions of the reference magnet and the float magnet, and the liquid level of the absorption liquid is obtained from this to determine the absorption liquid pump. Control the rotation speed of.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. It should be noted that parts having the same functions as those of the conventional device shown in FIGS. 4 and 5 are denoted by the same reference numerals, and description thereof is omitted within a range that does not hinder the understanding of the present invention.

FIG. 1 shows the main part of the apparatus configuration.
Reference numeral 0 denotes a magnetostrictive liquid level gauge fixedly installed on the top plate of the liquid level detection box 25, 40 denotes a temperature sensor for measuring the temperature of the absorbing liquid 27 flowing into the liquid level detection box 25, and 41 denotes a micro. It is a control device including a computer and the like, and controls the number of revolutions of the absorbing liquid pump 16 based on the data detected and output by the magnetostrictive liquid level gauge 30 and the temperature sensor 40.

In the magnetostrictive liquid level gauge 30, when an electric current is passed in the axial direction of a ferromagnetic material and a magnetic field is applied in parallel to the magnetic material, a magnetic field generated by the electric current and an external magnetic field are combined to give a spiral magnetic field. Phenomenon that causes magnetostriction (Wiedemann effect)
Was used,

A reference magnet 32 and a float magnet 33 are arranged around a magnetostrictive wire 31 made of a ferromagnetic material,
When a pulse current is applied to the current, each time the pulse current flows near the reference magnet 32 and the float magnet 33,
At each position, a momentary force acts on the magnetostrictive wire 31 to cause twisting, and this twisting propagates inside the magnetostrictive wire 31 at the speed of sound, so that the twisting phenomenon occurring at the positions of the reference magnet 32 and the float magnet 33 The distance between the reference magnet 32 and the float magnet 33 is measured by measuring the arrival time difference and multiplying by the sound velocity.

In this case, even if the surface of the magnetostrictive liquid level gauge 30 is contaminated with the absorbing liquid 27, the time until the pulse current flows through the magnetostrictive line 31 to cause twisting, and the speed at which the twisting propagates through the magnetostrictive line 31 are: Since it is not affected, the contamination of the magnetostrictive liquid level gauge 30 with the absorbing liquid 27 causes no problem in measuring the liquid level 28.

Specifically, the first twist generated when the pulse current passes near the reference magnet 32 fixed on the upper side and the float magnet 33 located on the lower side.
The second twist generated when the pulse current passes near the position of the pulse magnet is measured at the predetermined time, for example, at the upper end of the pulse transmission / detection unit 34 by measuring the time difference between the reference magnet 32 and the float magnet 33. Since the separation distance is accurately obtained, if the level of the reference magnet 32 is known, the level of the float magnet 33, that is, the level of the liquid surface 28 of the absorbing liquid 27 can be accurately detected.

The liquid level detection box 25 in which the magnetostrictive liquid level gauge 30 is installed is provided on the outer wall portion of the high temperature regenerator 1, and communicates with the inside of the high temperature regenerator 1 to absorb the absorbing liquid 27 and a refrigerant vapor (not shown). ) And liquid holes 25A and vapor holes 25B are provided at the upper and lower portions of the partition wall so that they can freely move in and out.

By installing the liquid level detection box 25 as described above, the absorption liquid 27 of the high temperature regenerator 1 and the absorption liquid 27 of the liquid level detection box 25 have almost the same temperature, and moreover, the combustion heating chamber. When the gas or oil is burnt in 2 to heat and boil the absorption liquid 27 of the high temperature regenerator 1 to evaporate and separate the refrigerant, the absorption liquid 27 in the liquid level detection box 25 is used.
Hardly foams. Therefore, the magnetostrictive liquid level gauge 30
Buoyancy of the float magnet 33 of the
The level of the liquid surface 28 can be accurately detected. The liquid level 28 thus obtained is equal to the substantial liquid level (not shown) of the boiling and bubbling absorption liquid 27 in the high temperature regenerator 1, and controls the rotation speed of the absorption liquid pump 16. Therefore, it is convenient for controlling the supply amount of the absorbing liquid 27 to the high temperature regenerator 1.

In FIG. 1, the reference magnet 32 is fixedly fixed to the magnetostrictive wire 31, and the float magnet 33 is made of a material having a small specific gravity, such as Teflon, for SUS31.
It is attached to a buoyancy member covered with 6, and is provided so as to move up and down according to the vertical movement of the liquid surface 28 of the absorbing liquid 27, and a pulse current is transmitted from the pulse transmission / detection unit 34, and this pulse current is used as a reference magnet. The first twist that occurs when passing near 32 and the second twist that occurs when the pulse current passes near float magnet 33 reach the pulse transmitting / detecting unit 34 by measuring the time difference ΔT. The distance between the reference magnet 32 and the float magnet 33 is measured by multiplying the time difference ΔT by the speed at which the torsion propagates through the magnetostrictive line 31 (sonic speed).

The control device 41 outputs the level data of the liquid level 28 output from the magnetostrictive liquid level gauge 30 to, for example, 1 to 5 V and 4 to 4.
It is for converting the electric signal of 20 mA or the like and outputting the electric signal to control the rotation speed of the absorbent pump 16.

Since the specific gravity of the absorbing liquid 27 increases as the temperature rises, the buoyancy of the float magnet 33 decreases. Therefore, even if the actual liquid level 28 is the same, the higher the temperature of the absorbing liquid is, the reference magnet 32
And the separation distance between the float magnet 33 and
As shown in FIG. 2, a small electric signal is output. Therefore, the data output by the magnetostrictive liquid level gauge 30 is calculated based on the temperature data of the absorbing liquid 27 detected by the temperature sensor 40.
It is desirable to correct it.

FIG. 3 shows an example (α = 1 at 20 ° C.) obtained by actually measuring the correction coefficient α when the absorbing liquid 27 is an aqueous solution of lithium bromide. Two
When the temperature T of 7 is 140 ° C., the correction coefficient α at this time is 1.08, so the value obtained by multiplying the liquid level output output by the magnetostrictive liquid level gauge 30 by 1.08 is the actual liquid level. The position is corrected and output from the control device 41, and the rotation speed of the absorbent pump 16 is controlled.

Since the present invention is not limited to the above embodiments, various modifications can be made without departing from the spirit of the claims. For example, the reference magnet 32 and the float magnet 33 can be attached upside down. If the reference magnet 32 is placed below and the float magnet 33 is placed above, the time difference measured by the pulse transmission / detection unit 34 can be directly displayed as the level of the liquid level 28.

[0025]

INDUSTRIAL APPLICABILITY As described above, the present invention is directed to an absorption refrigerator in which a high temperature regenerator, a low temperature regenerator, a condenser, an evaporator, an absorber, a heat exchanger, etc. are connected by piping to form a refrigeration cycle. , A wall surface of the high temperature regenerator is provided with a liquid level detection box that communicates with the inside of the high temperature regenerator and through which both the absorbing liquid and the refrigerant vapor can flow in and out. Install a magnetostrictive liquid level meter having a wire, a reference magnet, and a float magnet, and calculate the distance between the reference magnet and float magnet of this magnetostrictive liquid level meter to determine the liquid level of the absorbing liquid in which the float magnet floats. The absorption level characterized by controlling the liquid level of the high temperature regenerator by controlling the number of rotations of the absorption liquid pump installed between the absorber and the high temperature regenerator by the detected liquid level. Cold Machine is a liquid level control method,

A temperature sensor for detecting the temperature of the absorbing liquid is installed in the liquid level detecting box, and the output of the magnetostrictive liquid level gauge is subjected to temperature correction according to the output value of the temperature sensor. Since it is a liquid level control method,

The number of times the absorbent pump is turned on / off is extremely reduced, and the life of the absorbent pump is extended. In addition, since the liquid level of the absorbing liquid can be output as a linear signal, the circulating amount of the absorbing liquid can be controlled by controlling the number of revolutions of the absorbing liquid pump, and the operating performance during partial load can be improved. improves. Further, since the liquid level gauge is composed of one component, mechanical troubles such as air leaking from the installation portion are reduced. Further, since a voltage is not applied between the electrode rod and the ground electrode rod to flow a current through the absorbing liquid, the risk of corroding the liquid level detector or the main body of the absorption refrigerator is reduced. Further, even if the liquid is contaminated with the absorbing liquid, it is not affected in detecting the liquid surface, so that the maintenance is extremely easy and a remarkable effect is exhibited.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a device configuration (main part) of an embodiment.

FIG. 2 is an explanatory diagram showing an output of a magnetostrictive liquid level meter with respect to a liquid level.

FIG. 3 is an explanatory diagram showing a relationship between an absorbing liquid temperature and a correction coefficient.

FIG. 4 is an explanatory diagram showing a conventional technique.

FIG. 5 is an explanatory diagram showing another conventional technique.

[Explanation of symbols]

 1 High Temperature Regenerator 2 Combustion Heating Chamber 4 Low Temperature Regenerator 5 Condenser 7 Evaporator 9 Absorber 10 Low Temperature Heat Exchanger 11 High Temperature Heat Exchanger 16 Absorbing Liquid Pump 25 Liquid Level Detection Box 25A Liquid Hole 25B Vapor Hole 27 Absorbing Liquid 28 Liquid level 29 Capacitance type liquid level gauge 30 Magnetostrictive liquid level gauge 31 Magnetostrictive line 32 Reference magnet 33 Float magnet 34 Pulse transmission / detection section 40 Temperature sensor 41 Control device

Claims (2)

[Claims] 1. An absorption chiller in which a refrigeration cycle is configured by connecting a high temperature regenerator, a low temperature regenerator, a condenser, an evaporator, an absorber, a heat exchanger, etc. to a wall of the high temperature regenerator. A liquid level detection box that communicates with the inside of the high-temperature regenerator and through which both the absorbing liquid and the refrigerant vapor can flow in and out is provided, and this liquid level detection box has a magnetostrictive line, a reference magnet, and a float magnet. Install a meter, calculate the distance between the reference magnet and float magnet of this magnetostrictive liquid level meter to determine the liquid level of the absorbing liquid in which the float magnet floats, and use this detected liquid level to determine that the absorber A liquid level control method for an absorption chiller, comprising controlling the number of revolutions of an absorption liquid pump installed between the high temperature regenerator and the liquid level of the high temperature regenerator. 2. The liquid level detection box is provided with a temperature sensor for detecting the temperature of the absorbing liquid, and the output of the magnetostrictive liquid level gauge is temperature-corrected according to the output value of the temperature sensor. Item 1. A liquid level control method for an absorption chiller according to Item 1.