JP2000074509A - Flooded cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flooded cooler which uses ammonia as a refrigerant, can highly efficiently cool by using a small amount of low-temperature low- pressure refrigerant solution, and can separate and collect oil from the refrigerant solution. SOLUTION: A flooded cooler using an ammonia refrigerant is provided with a heat exchanger 10 constituting an evaporator, a refrigerant solution charging section composed of a vertical refrigerant solution separating and supplying pipe 11 and an internal equalizer 12, and a cold gas charging section composed of a vertical refrigerant gas returning pipe 13 and a horizontal refrigerant gas tank 14 as principal components. The refrigerant solution charging section and the refrigerant gas charging section are separated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-fill type cooler for cooling a medium to be cooled by filling a heat exchanger forming an evaporator using only a refrigerant liquid of a low-temperature low-pressure refrigerant.

[0002]

2. Description of the Related Art As a refrigeration cycle in which an evaporator is filled with only a refrigerant liquid of a low-temperature and low-pressure refrigerant, as shown in FIG. 2A, a high-pressure and high-temperature refrigerant gas compressed by a compressor 50 is supplied to an oil separator. The refrigerant becomes a high-pressure low-temperature refrigerant via a condenser 52 and is introduced into a high-pressure receiver 53. In the high-pressure receiver 53, the received high-pressure low-temperature refrigerant is introduced as a low-pressure low-temperature refrigerant into the low-pressure receiver 57 via the expansion valve 55, and the introduced refrigerant liquid of the low-pressure low-temperature refrigerant is supplied via the adjustment valve 60 by the liquid pump 58. There is a liquid pump system in which the refrigerant gas is sent to the evaporator 56 and the unevaporated component is removed from the returned refrigerant gas and returned to the compressor. The pressure on the outlet side of the liquid pump 58 is kept constant by the pressure relief valve 59, and
The pressure is reduced to a value corresponding to the pressure loss in the evaporator 56 by 0, and the liquid is sent to each evaporator 56. Therefore, wet vapor of the refrigerant exists at the outlet of the evaporator 56. As shown in FIG. 2B, the high-pressure high-temperature refrigerant gas compressed by the compressor 50 becomes a high-pressure low-temperature refrigerant via the oil separator 51 and the condenser 52 and is introduced into the high-pressure receiver 53. From the high-pressure receiver 53, via a expansion valve 55 and a float valve (not shown), the surge tank 62 uses a surge tank that constantly maintains the liquid level of the low-pressure low-temperature refrigerant at the liquid level H in the surge tank 62. There is a natural circulation system. In the above case, the refrigerant pressure at the inlet of the evaporator 61 has a pressure corresponding to the liquid level H. In the process of the refrigerant flowing through the evaporator, friction of the flow, acceleration of vapor due to evaporation,
The pressure of the two-phase refrigerant by the static pressure head or the like drops, and the pressure at the evaporator outlet becomes the same as that of the upper part of the surge tank, and wet steam of the refrigerant exists at the outlet. As described above, since the refrigerant liquid exists up to the outlet end of the evaporator in any of the methods, the heat transfer area can be used to the maximum, and efficient and stable cooling operation can be performed.

[0003]

Incidentally, in a conventional liquid-filled refrigeration cycle in which an evaporator is filled with a low-temperature refrigerant liquid, it is necessary to fill a large amount of refrigerant in a cooling device provided with the evaporator. Currently, safe and easy-to-use CFC refrigerants that have been used for a long time have been regulated due to the problem of ozone layer depletion affecting the global environment and the issue of global warming. It has been reviewed. That is, the ammonia refrigerant has no danger of destruction of the global environment like CFCs, and its refrigeration effect is as good as CFCs, and has the advantage of being inexpensive. But,
Ammonia has problems such as toxicity, flammability, and insolubility in mineral oil used as a lubricating oil, as replaced by CFCs in the past, and high discharge temperature from the compressor. . In particular, there is a problem that a device that fills a large amount of ammonia refrigerant in the cooling device cannot be installed from the viewpoint of safety.

In addition, a conventional heat exchanger comprising a copper pipe used for chlorofluorocarbon gas and the like cannot be used because ammonia itself is corrosive to copper-based materials, so that the apparatus becomes large and the amount of refrigerant charged increases. There's a problem. Further, since ammonia refrigerant is insoluble in mineral oil, which is a conventional refrigeration oil, a forced circulation system using a liquid pump is adopted so that the refrigeration oil does not remain in the evaporator, the apparatus becomes large, and the amount of refrigerant charged increases. There is a problem that tends to.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. In a liquid-fill type cooler using ammonia as a refrigerant, a small amount of a low-temperature low-pressure refrigerant liquid enables high-efficiency cooling and an oil-based refrigerant liquid. It is intended to provide a liquid-filled cooler that enables separation and recovery.

[0006]

In view of the above, a liquid-filled cooler according to the present invention is not limited to a conventional storage tank in which a refrigerant liquid and a refrigerant gas are accommodated in the same container, but is filled with a refrigerant liquid. The part and the filling part of the refrigerant gas are separately prepared so that the part filled with the refrigerant liquid is minimized. That is,
Filling the heat exchanger forming the evaporator only with the low-temperature low-pressure refrigerant liquid and separating the refrigerant liquid from the heat exchanger that fills the refrigerant liquid in the gravity-supply type liquid-liquid cooler that cools the medium to be cooled. A refrigerant liquid filling section comprising an upright refrigerant liquid separation / supply pipe to be supplied, an internal pressure equalizing pipe connecting the two, and a refrigerant gas filling section comprising a horizontal refrigerant gas tank for returning refrigerant gas to a compressor. It is characterized by.

Further, the upright refrigerant liquid separation / supply pipe according to claim 1 receives supply of low-pressure low-temperature refrigerant through an expansion valve,
Separates only the refrigerant liquid and supplies gravity to the heat exchanger under the head that overcomes pressure loss, has an oil reservoir at the bottom, and has a cross-sectional area determined by the refrigerant circulation amount and the gas velocity of the refrigerant gas. The internal pressure equalizing pipe is configured to be connected to the lower part of the upright refrigerant liquid separation / supply pipe at an upward gradient from the lower part to the bottom of the heat exchanger, and the horizontal refrigerant gas tank is used when the upright refrigerant liquid separation / supply pipe expands to low pressure refrigerant. It is characterized in that the generated refrigerant gas and the vaporized refrigerant gas from the heat exchanger outlet are introduced so that only the refrigerant gas is returned to the compressor.

With the above arrangement, the liquid-fill type cooler of the present invention mainly comprises an upright refrigerant liquid separation / supply pipe filled with refrigerant liquid, an internal pressure equalizing pipe, a heat exchanger, and a horizontal refrigerant gas tank filled with refrigerant gas. In addition, a liquid-fill type cooler is formed by using a small amount of refrigerant by minimizing the volume of a portion filled with the refrigerant liquid. That is, a configuration in which only the refrigerant liquid of the low-pressure low-temperature refrigerant supplied from the high-pressure liquid receiving section via the expansion valve is separated, and an upright refrigerant liquid separation / supply pipe for maintaining the liquid level in the head overcoming the heat exchanger pressure loss is provided. Therefore, the heat exchanger receiving the supply of the refrigerant liquid from the refrigerant separation / supply pipe is placed in a liquid full state in which the wet vapor of the refrigerant exists up to the outlet thereof, and in the case of the ammonia refrigerant, the superheated vapor is sucked and compressed. No, high efficiency cooling is possible.

Further, since the upright refrigerant liquid separation / supply pipe is directly connected to the upper horizontal refrigerant gas tank,
The refrigerant gas contained in the low-pressure low-temperature refrigerant supplied through the expansion valve from the high-pressure low-temperature liquid receiving section separates and rises from the refrigerant liquid in the refrigerant liquid separation supply pipe, and only the refrigerant liquid is provided at the lower part of the supply pipe. Is stored separately and sent to a heat exchanger.
Further, by the refrigerant gas return upright pipe extending upright from the upper outlet of the heat exchanger, only the refrigerant gas vaporized by the heat taken from the medium to be cooled is separated from the wet steam,
Since it is configured to be introduced into the horizontal refrigerant gas tank provided at the upper part, the wet steam is not returned to the compressor.

The cross-sectional area of the upright refrigerant liquid separation and supply pipe is determined by the refrigerant circulation amount and the gas velocity determined from the refrigerant gas amount generated by the vaporization of the refrigerant in the heat exchanger. The amount of the refrigerant liquid filled in the refrigerant separation and supply pipe can be minimized.

The container filled with the refrigerant gas is formed by a separately prepared horizontal refrigerant gas tank, and the refrigerant gas separated from the low-pressure low-temperature refrigerant filled in the upright refrigerant liquid separation supply pipe and the refrigerant gas vaporized in the heat exchanger Is introduced into the horizontal refrigerant gas tank, so that a minimum amount of ammonia can be prepared with respect to the refrigerant circulation amount. There is no need to use a large amount of ammonia refrigerant as in the type cooler.

Further, since the internal pressure equalizing pipe is provided with a rising gradient toward the bottom of the heat exchanger, the oil accumulated at the inlet on the bottom side of the heat exchanger descends along the pressure equalizing pipe to separate the upright refrigerant liquid. It is stored in an oil sump provided at the bottom of the supply pipe, and is appropriately recirculated together with the refrigerant gas at the time of suction of the compressor.

Further, the horizontal refrigerant gas tank according to the present invention is characterized in that the horizontal refrigerant gas tank is provided with a steam pressure control multi-function valve which operates according to the gas pressure of the refrigerant gas and the temperature difference between the inlet and the outlet of the medium to be cooled. It is assumed that.

According to the above construction, the suction of the refrigerant gas from the compressor is controlled by the gas pressure in the horizontal refrigerant gas tank filled with the refrigerant gas and the difference in the temperature of the chilled water at the inlet and outlet of the medium to be cooled, which is a cooling load. It is.

Further, the heat exchanger according to the first aspect is characterized by comprising a plate heat exchanger.

According to the above configuration, an evaporator having a high resistance to the corrosiveness of the ammonia refrigerant can be prepared.

Further, the refrigerant according to claim 1 is an ammonia refrigerant.

That is, according to the present invention, a heat exchanger having a high resistance to the use of an ammonia refrigerant is used, and the use of a liquid-filled evaporator having a high cooling efficiency for the use of the refrigerant is reduced to a small amount of ammonia. It can be made possible with a refrigerant.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an embodiment shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not merely intended to limit the scope of the present invention, but are merely illustrative examples unless otherwise specified. Absent.

FIG. 1 is a diagram showing a schematic configuration of a liquid-fill type cooler using an ammonia refrigerant of the present invention. As shown in the figure, a liquid-fill type cooler using the ammonia refrigerant of the present invention is a refrigerant liquid filling system comprising a heat exchanger 10 forming an evaporator, an upright refrigerant liquid separation / supply pipe 11 and an internal pressure equalizing pipe 12. Section, refrigerant gas return upright pipe 13 and horizontal refrigerant gas tank 14
The refrigerant gas filling section and the suction pipe 15 are main components, and the refrigerant liquid filling section and the refrigerant gas filling section are separated and separated from each other, so that the refrigerant to be used is minimized.

The upright refrigerant liquid separation / supply pipe 11 introduces a low pressure low temperature refrigerant from a high pressure receiver (not shown) through a float type liquid supply solenoid valve 11e and an expansion valve 11g. The introduced low-pressure low-temperature refrigerant liquid is provided in the upright pipe 11c for level detection,
The solenoid valve 11e is operated via a float switch 11d composed of LC ₃ , LC ₂ , and LC ₁ for detecting the middle and lower liquid levels, and the pressure of the heat exchanger is formed from the outlet of the heat exchanger 10 forming an evaporator. Liquid level Y with head H corresponding to loss
Is maintained. As described above, the refrigerant gas generated at the time of passing through the expansion valve and contained in the low-pressure low-temperature refrigerant is separated from the refrigerant liquid indicated by the hatching in the upright refrigerant separation / supply pipe 11 and rises to the upper space 11a, which will be described later. It is introduced into the horizontal refrigerant gas tank 14. The separated refrigerant liquid is stored in an upper part of an oil reservoir 11b provided at a lowermost end of the upright refrigerant separation and supply pipe 11. The stored refrigerant liquid is passed through the internal pressure equalizing pipe 12 provided at a rising gradient toward the heat exchanger 10 as shown by a solid arrow in the heat exchanger 10.
Of the heat exchanger 10 by the head H.
To form an overflow evaporator.

The oil separated in the heat exchanger 10 accumulates at the bottom of the heat exchanger and is stored in the oil sump 11b via the internal pressure equalizing pipe 12 as shown by a dotted arrow. The stored oil is turned on by an oil recovery circuit 12b and a compressor (not shown).
It is configured to be sent to and recovered from the compressor suction circuit 15 via the electromagnetic valve 12a linked to OFF.

At the outlet of the heat exchanger 10, there is provided a refrigerant gas return upright pipe 13 for connecting with a horizontal refrigerant gas tank 14 disposed at the upper part, so that the vaporized refrigerant gas generated in the heat exchanger 10 is recovered. It is. As described above, the horizontal refrigerant gas tank 14 is filled with the expanded refrigerant gas contained in the low-pressure low-temperature refrigerant separated from the upright refrigerant separation / supply pipe 11 and the vaporized refrigerant gas in the heat exchanger 10. You.
The charged refrigerant gas is recovered to a compressor (not shown) via the multi-function valve 16 and the suction pipe 15. The multi-function valve 16 includes a CVQ function 16a, a P function 16b, and an SV
It has a function 16c. The CVQ function 16a is a heat exchanger 1
The P function 16b is an EPR function for adjusting the evaporation pressure, and the SV function 16c is an ON / OFF function. The use of the multi-function valve 16 keeps the cold water temperature difference at 0.5 ° C.

The upright refrigerant separation / supply pipe 11 has a cross-sectional area determined by the amount of circulating refrigerant and the gas velocity of the refrigerant gas, and is configured to minimize the amount of refrigerant charged.

The heat exchanger 10 employs a plate heat exchanger that does not use a copper member, and is configured to have resistance to corrosion of the ammonia refrigerant.

[0026]

According to the above structure, the low-temperature refrigerant is filled in the upright refrigerant liquid separation / supply pipe having the low-pressure liquid level and the plate heat exchanger, both of which have small volumes. For this reason, the increase in the amount of charged refrigerant is smaller than that in the dry cooling device. For example, even if an ammonia refrigerant is used, a compact, stable, and highly efficient cooling device can be provided using a conventional refrigerating machine oil and having the same refrigerant charging amount as a conventional dry cooling device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a liquid-fill type cooler using an ammonia refrigerant of the present invention.

FIG. 2 is a diagram showing an outline of a conventional cooling device, wherein (A) is of a liquid pump circulation type and (B) is of a gravity natural circulation type.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Heat exchanger 11 Upright refrigerant liquid separation supply pipe 11b Oil reservoir 12 Internal pressure equalization pipe 13 Refrigerant gas return upright pipe 14 Horizontal refrigerant gas tank 15 Suction pipe 16 Multifunctional valve

Claims (5)

[Claims] 1. A gravity-supply type liquid-fill type cooler that fills a heat exchanger forming an evaporator only with a low-temperature and low-pressure refrigerant liquid and cools a medium to be cooled, comprising: a heat exchanger that fills the refrigerant liquid; A refrigerant liquid filling section comprising an upright refrigerant liquid separation / supply pipe for separating and supplying a refrigerant liquid and an internal pressure equalizing pipe connecting the two, and a refrigerant gas filling section comprising a horizontal refrigerant gas tank for returning refrigerant gas to the compressor. A liquid-filled cooler characterized by being separated. 2. The upright refrigerant liquid separation supply pipe receives a supply of low-pressure low-temperature refrigerant through an expansion valve, separates only the refrigerant liquid, and supplies the heat exchanger with gravity under a head that overcomes pressure loss. At the same time, it has an oil reservoir at the bottom and has a cross-sectional area determined by the refrigerant circulation amount and the gas velocity of the refrigerant gas, and the internal pressure equalizing pipe rises from the lower part of the upright refrigerant liquid separation supply pipe toward the bottom of the heat exchanger. The horizontal refrigerant gas tank introduces a refrigerant gas generated when expanding into a low-pressure refrigerant from an upright refrigerant liquid separation supply pipe, and a vaporized refrigerant gas from a heat exchanger outlet, and compresses the refrigerant gas. A liquid-filled cooler characterized in that only refrigerant gas is recirculated to the machine. 3. The multifunction valve according to claim 1, wherein the horizontal refrigerant gas tank is provided with a steam pressure control multi-function valve that operates according to the gas pressure of the refrigerant gas filled therein and the temperature difference between the inlet and the cold water of the medium to be cooled. The liquid-filled cooler according to claim 1. 4. The liquid-fill type cooler according to claim 1, wherein said heat exchanger comprises a plate heat exchanger. 5. The liquid-fill type cooler according to claim 1, wherein the refrigerant is an ammonia refrigerant.