JPS5828960A - Controller for flow rate - 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 The present invention relates to a vapor compression type refrigeration system that utilizes the latent heat of a refrigerant, and particularly to a flow rate control device for the refrigerant.

Figure 1 shows an example of the refrigerant cycle of a conventional refrigeration system. In the figure, (1) is a compressor, (2) is a condenser, (8) is a pressure reducing device, and (4) is an evaporator. Yes, these are connected in sequence to form a refrigeration system.

In such conventional refrigeration equipment, refrigerant gas that has become high temperature and high pressure in the compressor (1) is cooled and liquefied in the condenser (2), becomes low temperature and low pressure in the pressure reducing device (8), and is then transferred to the evaporator ( 4
). When the refrigerant liquid is gasified in the evaporator (4), it absorbs heat from the surroundings and performs freezing. After this, the refrigerant gas is sucked into the compressor (1).

In such a refrigeration system, it is known that the appropriate flow rate of refrigerant varies depending on the evaporation temperature, and normally, as the evaporation temperature increases, a larger flow rate of refrigerant is required. However, in conventional refrigeration equipment as shown in Figure 1, the adjustment of the refrigerant flow rate is insufficient, resulting in insufficient refrigerant flow rate when the evaporation temperature is high, and the degree of superheating of the refrigerant at the evaporator outlet becomes too large, resulting in compression failure. There were disadvantages such as when the temperature of the compressor rose or when the evaporation temperature was low, the refrigerant flow rate became excessive, causing liquid backflow in the compressor.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and provides a flow rate control device that can maintain an appropriate flow rate of refrigerant by cooling a pressure reducing device and adjusting the amount of cooling. The purpose is to

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 and FIG. 8 show the configuration of one embodiment, and the same parts as in FIG. 1 are given the same reference numerals, and the explanation thereof will be omitted. In Fig. 2, (5) is a cooling liquid, (6) is a pump that circulates the cooling liquid, (7) is a flow rate adjustment valve that adjusts the flow rate of the 1i cooling liquid, (8) is a valve control device, and (9) is a This is a heat exchange section between cooling liquid and refrigerant. Moreover, FIG. 8 shows the structure of the heat exchange section when a capillary tube (8a) is used as a pressure reducing device, where ■ is a tube and α0) is a heat insulating material.

In the flow control device configured as described above, the refrigerant in the pressure reducing device (8) is circulated by the pump (6).
6) Alternatively, it can be cooled in the heat exchange section (9). Further, the amount of cooling can be adjusted by increasing or decreasing the flow rate of the coolant using a flow rate adjustment valve (γ) inserted into the coolant circuit. Here, the opening degree of the flow rate adjustment valve (7) is determined by a valve lift adjustment device (8) that uses an electrical or mechanical method.
), so that, for example, the outlet temperature of the evaporator (4) is always slightly higher than the inlet temperature, the refrigerant is completely gasified at the outlet of the evaporator and slightly superheated, so that the refrigerant is always at an appropriate level. Flow rate can be maintained as supplied.

Incidentally, the relationship between the cooling amount and the refrigerant flow rate shows a tendency that the refrigerant flow rate increases as the cooling amount increases, as shown in FIG. This is because the gas content in the two-phase flow of refrigerant generated in the capillary tube decreases as the amount of cooling increases, and the fluid resistance decreases and the refrigerant flow rate increases.

By utilizing this characteristic, for example, the valve lift of the flow rate regulating valve can be changed depending on the temperature at the inlet and outlet of the evaporator (4), and the amount of cooling of the refrigerant can be controlled, so that the refrigerant flow rate can always be appropriately controlled.

Although the above embodiment describes the case where the refrigerant in the pressure reducing device is cooled, the same effect can be obtained by cooling the refrigerant at the inlet of the pressure reducing device.

1*. In the above embodiment, an external cooling source is used, but as in No. 5S, a part of the refrigerant liquid at the outlet of the condenser (2), or as in Fig. 2) A refrigerant taken out from the middle and reduced in pressure to a low temperature may be used as the cooling source. Also, this low-temperature refrigerant is not necessarily as shown in Figure 6.
There is no need to flow it to the inlet side of the evaporator (4) as shown in Figure 6, but into the suction pipe of the compressor (1) as shown in Figure 7, or to the evaporator (4) in Figure 8. Intermediate, pressure reducing device (8
) may be anywhere where the pressure is lower than the upstream side of the flow rate regulating valve (7).

Furthermore, the extraction of low-temperature refrigerant is not limited to the middle or outlet of the condenser (2), but as shown in Fig.
11, the outlet of the pressure reducing device (3) as shown in FIG.
The same effect can be achieved by using a portion of the compressor suction gas.

Furthermore, even in a device having two or more pressure reducing devices as shown in FIG. 18, the same effect can be achieved by controlling the flow rate of some of them by 1; It goes without saying that the same effect can be obtained even when heat is exchanged between the suction pipe (11) and the heat exchange section (b) as shown in FIG. “Although the above example shows a simple refrigeration system, in addition to this simple refrigeration system, there is a four-way switching valve (6), an indoor heat exchanger (b), a check valve
Even in a pump system equipped with an outdoor heat exchanger (b), etc., the flow rate of the refrigerant can be maintained at an appropriate level using the circuits shown in Figures 16, 16, and 17. It can also be applied to other refrigeration systems such as refrigeration cycles and multi-stage cascade cycles, and the same effect can be achieved even in systems equipped with auxiliary equipment such as oil separators and dryers.

Furthermore, not only such a refrigeration cycle but also a system in which a gaseous body is condensed by cooling in a two-phase flow can similarly control the flow rate. In addition, the solid line arrow in the figure indicates the heating circuit, and the dotted line arrow indicates the cooling circuit.

In addition, if heat transfer is increased by attaching fins or inserting spiffle tape to the heat exchange section through which the coolant flows, as shown in Fig. 18, heat exchange will be improved and performance can be further improved.

The flow rate of the low-temperature refrigerant is controlled not only by a flow rate regulating valve that changes the valve lift 'E, but also by using an insert (c) with a micro-shaped groove (in the micro-shaped groove) that is brought into close contact with the inner wall of the pipe, as shown in Figure 20. The device has a structure in which an electric heater (2) is wrapped around the outside of a tube (c) inserted into the tube, and the flow rate or liquid volume can be adjusted by increasing or decreasing the input to the electric heater, as shown in Figure 19. Any device that can adjust the flow rate of the low-temperature refrigerant may be used, such as a configuration that allows for adjustment of the flow rate of the low-temperature refrigerant.

Moreover, as shown in FIG. 21, if an electric heater or the like is attached to the inlet of the pressure reducing device to heat the refrigerant and adjust the flow rate, even smoother control can be achieved.

As described above, according to Jin's invention, the flow rate control device is configured to cool the refrigerant at the pressure reducing device or the inlet of the pressure reducing device, and adjust the amount of cooling to adjust the flow rate of the refrigerant. An appropriate refrigerant flow rate can always be maintained in response to changes in conditions, and a refrigeration system with high reliability and good performance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cycle diagram of a refrigeration system using a conventional refrigerant flow rate control device, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 8 is a diagram showing the structure of a pressure reducing device according to the present invention. FIG. 4 is a diagram showing the characteristics of the refrigerant flow rate with respect to the cooling amount when cooling a pressure reducing device, and FIGS. 6 to 4 are diagrams showing other embodiments of the present invention. In the figure, (1) is the compressor, (2) is the condenser, (3) is the pressure reducing device, (4) is the evaporator, (5) is the cooling liquid, (6) is the pump, and (7) is the flow rate adjustment. valve, (8) is a valve lift adjustment device,
(9) is the heat exchange section, M is the insulation material, (b) ore suction pipe, (b) is the suction pipe bypass, (b) is the heat exchange section, (b) is the four-way switching valve, (b) is the indoor heat exchange device, Q6) Fi check valve, aη
08) is an outdoor heat exchanger, 08) is a flow rate adjustment device, (B) is an electric input adjustment device, - is a power supply, Ql) is an insulation material, ni) is an electric heater, ■ is a pipe, (c) is an insert, ni) is a groove. In the drawings, the same reference numerals indicate the same or corresponding parts. Fig. 1 Fig. 2 Fig. 3 Fig. 4 Small company f- Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 1θ Fig. 11 Fig. 2 12ff1 Fig. 1J Fig. 14 Fig. 15 Figure 16

Claims (1)

[Scope of Claims] (1) A flow rate control device characterized in that the flow rate is controlled by adjusting the amount of cooling of a pressure reducing device or a fluid at the inlet of the pressure reducing device. (2) The flow rate control device according to claim 1, wherein cooling is performed using a low-temperature refrigerant, and the flow rate of the refrigerant is controlled by an electrical or mechanical control valve. (8) The flow rate control device according to claim 2, characterized in that cooling is performed using a low-temperature refrigerant produced by reducing the pressure of the refrigerant liquid from the condenser (4) Cooling is performed by a pressure reducing device 3. The flow rate control device according to claim 2, wherein the flow rate control device is characterized in that the flow rate is controlled by low-temperature refrigerant from an intermediate or outlet of the flow rate control device. (6) The flow rate control device according to claim 2, characterized in that cooling is performed by a low-temperature refrigerant at the outlet of the evaporator. (6) The flow rate of the low-temperature refrigerant is controlled by inserting an insert having a spifle-shaped groove between the inner wall of the pipe and heating the insert from the outside. The flow rate control device according to any one of items 6 to 6.