JPS6144126Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an improved configuration of a refrigeration system, and is particularly aimed at preventing freezing due to pump-down operation of drain water after defrosting frost attached to a drain pan using hot gas. be.

A conventional refrigeration system has a compressor 1 as shown in Figure 1.
A condenser 2, an expansion valve 3, and an evaporator 4 are connected via piping to form a refrigeration cycle. 5 is the compressor 1
and the condenser 2, and one of the three-way valves bypasses the condenser 2 and connects the evaporator 4.
It is connected to a hot gas bypass pipe 8 having a drain pan heating pipe 7 disposed for heat exchange in a drain pan 6 that receives drain water. 9 is a liquid pipe solenoid valve provided between the condenser 2 and the expansion valve 3.

In the above configuration, since the three-way valve 5 is open to the condenser 2 side during cooling operation, the discharged gas compressed by the compressor 1 is liquefied in the condenser 2 and then transferred to the expansion valve 3, as shown by the solid arrow. It is depressurized in the evaporator 4, vaporized in the evaporator 4, performs a cooling action, and then returned to the compressor 1.
During defrosting operation, the three-way valve 5 is open to the hot gas bypass pipe 8 side, so the high-temperature discharge gas compressed by the compressor 1 flows into the hot gas bypass pipe 8 as shown by the dotted arrow and flows into the drain pan heating pipe. 7
After melting the frost or ice that adheres to the drain pan 6 while passing through, the evaporator 4 is defrosted and returned to the compressor 1.

However, since the hot gas that defrosts the evaporator 4 is first heated in the drain pan heating pipe 7 that melts frost and ice adhering to the drain pan 6, when defrosting the evaporator 4, the defrosting ability decreases and the defrosting time is reduced. As the time becomes longer, after defrosting is completed, the three-way valve 5 is opened to the condenser 2 side, and the liquid pipe solenoid valve 9 is closed to perform pump-down operation to prevent liquid compression and overload operation during recooling operation. However, since the pressure drops rapidly, the liquid refrigerant re-evaporates and, in particular, water droplets remaining in the drain pan 6 are cooled by the drain pan heating pipe 7 and freeze.

This proposal was made to solve the above problem, and the embodiment shown in FIG. 2 will be described below.

Note that the same parts in the figure as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted.

The difference from the conventional example shown in FIG. 1 is that a solenoid valve 10 is provided on the outlet side of the drain pan heating pipe 7 of the hot gas bypass pipe 8.

Therefore, the cooling operation and the defrosting operation constitute almost the same cycle as the conventional example shown in FIG. Drain pan heating pipe 7
When the solenoid valve 10 provided on the outlet side of The valve 10 shuts off the refrigeration cycle and the liquid refrigerant remains stored inside and does not evaporate again, so water droplets remaining in the drain pan 6 are cooled and do not freeze, and the liquid pipe solenoid valve 9 opens to resume cooling operation. Even if water enters the drain pan, the sensible heat of the liquid refrigerant stored in the drain pan heating pipe 7 heats the drain pan 6 to prevent the drain water from freezing.

In the above explanation, the drain pan heating pipe was connected in series to the hot gas bypass pipe 8 which is opened only during defrosting, or as shown in Fig. A structure in which a part of the drain pan heating pipe 7 is used as the drain pan heating pipe 7, and an on-off valve 11 that is closed only during pump down operation is provided in the liquid pipe between this heating pipe and the expansion valve 3, also allows the pump to down as shown in Fig. 2. It is possible to prevent the liquid refrigerant from reevaporating in the drain pan heating pipe 7 during operation, and in this case, the high temperature refrigerant flows through the drain pan heating pipe 7 even during cooling operation, so that the water droplets in the drain pan 6 are prevented from freezing. Nothing happened,
Even when the defrosting operation starts again and the hot gas passes through the drain pan heating pipe 7, it is not cooled by the drain pan 6, so the hot gas can flow into the evaporator 4 while still at high temperature, improving the defrosting ability and This has the additional effect of shortening the draining time after defrosting.

As described above, the proposed method connects the compressor, condenser, expansion valve, and evaporator with piping in this order, and connects the discharge side of the compressor and the inlet side of the evaporator with a hot gas bypass pipe for defrosting. In the refrigeration system, a part of the hot gas bypass pipe is arranged as a drain pan heating pipe in a heat exchange manner to the drain pan of the evaporator, and a defrosting pipe is provided between the evaporator and the drain pan heating pipe. Since it is equipped with a solenoid valve that is blocked during pump-down operation after defrosting, the liquid refrigerant in the drain pan heating pipe will remain stored in the pipe even if pump-down operation begins after defrosting. This prevents the drain water remaining in the drain pan from freezing.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram showing a conventional example, FIG. 2 is a refrigeration cycle diagram showing one embodiment of the present invention, and FIG. 3 is a refrigeration cycle diagram showing another embodiment. 1... Compressor, 2... Condenser, 3... Expansion valve,
4... Evaporator, 6... Drain pan, 7... Drain pan heating pipe, 10... Solenoid valve.

Claims (1)

[Scope of utility model registration request] A compressor, a condenser, an expansion valve, and an evaporator are connected via piping in this order, and the discharge side of the compressor and the inlet side of the evaporator are connected by a hot gas bypass pipe for defrosting, and the hot gas In a refrigeration system in which a part of a gas bypass pipe is arranged as a drain pan heating pipe in a heat exchange manner in a drain pan of the evaporator, between the evaporator and the drain pan heating pipe,
A refrigeration system characterized by being provided with a solenoid valve that is closed during pump-down operation after completion of defrosting.