JPS6284261A - Refrigerator - 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] [Field of Industrial Application] The present invention is applicable to refrigeration equipment used in a group of refrigerators and freezer showcases installed in multiple locations such as supermarkets, that is, refrigeration equipment with large load fluctuations. The present invention relates to a refrigeration system that can be operated in an optimal state at all times.

[Conventional technology]

Conventionally, this type of equipment is shown in Figure 2.
is multiple showcases (2a), (2b), (
This is a cooling device configured with the combination of 2c). Parallel compression refrigeration equipment (1) has a compressor with a rated capacity ratio of approximately 2 to 2 on a receiver connected downstream of a water-cooled condenser (la) or an air-cooled condenser (not shown). Two large-capacity compressors (lb) and small-capacity compressors (IC) selected as 1 are installed in parallel, and the refrigerant discharge pipes of each compressor (1b) and (IC) are installed in parallel. (1d) and suction pipe (1e) are connected in parallel to each other. t, (1f) is each person Ii
+(i) This is a pressure equalizing oil pipe that connects the crank chambers of (Ib) and (IC) to each other.

In addition, (5) is the refrigerant pressure set by the pressure setting unit (4) that sets the refrigerant pressure on the low pressure side to be converged with the output signal of the pressure detection unit (3) that detects the refrigerant pressure on the low pressure side. This is a control unit that individually controls the operation and stopping of the compressors (lb) and (1c) according to the pressure difference between the compressors (lb) and (1c).

Further, as shown in FIG. 8, the normal pressure region includes the capacity increase pressure value set by the pressure setting section (4),
Depending on the eight factors, capacity down pressure value and low pressure cut value, parallel compression type refrigeration system (in the area above the up pressure value of each company that sends the up signal to (1)) and parallel compression type refrigeration system (
If both a capacity down signal and a capacity up signal are output in 1), the area e → is equal to or higher than the capacity down pressure value and less than the capacity up pressure value, and the capacity down pressure value that outputs a capacity down signal to the parallel compression refrigeration system (1). It is divided into four areas: (0) where the pressure is lower than the low pressure cut group and (A) where the parallel compression type refrigeration system (1) is issued a false stop signal.

Further, (6) is a duty unit that forcibly stops the compressors (lb) and (lc) at regular intervals regardless of the pressure signal.

Next, the operation will be explained. For example, a cooling device (22
If the required power to obtain the required refrigerating capacity for the refrigerating load is 15) f, one compressor (lb)
The rated capacity of the other compressor (lc) is selected as toH), and the rated capacity of the other compressor (lc) is selected as 5)P.

On the other hand, multiple showcases (2a), (2b), (
In the cooling device (2) consisting of 2c), the cooling load varies greatly from 0 to 100% depending on the usage status of each showcase.

When the refrigeration load decreases, the refrigerant pressure on the low-pressure side of the refrigeration cycle decreases, and the pressure detection part (3)
The level of the pressure detection signal outputted to the control unit (5) also decreases.

The control section (5) has a comparison circuit that compares the pressure detection signal with a reference value (capacity up pressure value or capacity down pressure value), so if the pressure detection signal is lower than the capacity down pressure value, , that is, in the case of area (b),
The control unit (5) controls the capacity of the parallel compression type refrigeration device (1) to decrease, thereby lowering the cooling capacity. When the cooling capacity is lowered in this manner, the refrigerant pressure on the low pressure side of the refrigeration cycle increases and converges to region (c), and the operation becomes stable.

Additionally, when the cooling load is heavy, the refrigerant pressure on the low pressure side of the refrigeration cycle increases, and the level of the pressure detection signal output from the pressure detection unit (3) to the control unit (5) increases accordingly. do. As a result, if the pressure detection signal is higher than the capacity-up pressure value (in other words, in the area), the control unit (5) controls the parallel compression refrigeration system (υ) so that the capacity increases, Increase the cooling capacity. When the cooling capacity increases in this way, the refrigerant pressure on the low pressure side of the refrigeration cycle decreases and converges to the region (c), and the operation becomes stable. Note that the pressure detection part (3) If! (5) The time until the capacitance up signal or capacitance down signal is generated is the same.

In addition, if the refrigerant pressure on the low pressure side of the refrigeration cycle is below the low pressure cut value, that is, in the area (a), the compressor (xb)
, (lc) is designed to stop immediately.

Therefore, for the above refrigeration load fluctuation, the refrigeration load is 8
At a partial load of 8% or less, only the compressor (lc) with the rated valley jlL 5 )P is operated independently. Also, when the refrigeration load is in the range of 88 to 66%, the rated capacity! 10) P compressor (l
Only b) is operated independently.

Furthermore, when the refrigeration load reaches 66 to 100%, the compressor (l
b) and (lc) are operated in parallel at the same time. The transition of this @wind control operation is shown in Figure 4.

That is, as shown in FIG. 4, by selectively operating and stopping large and small compressors whose rated capacity ratio is selected to be approximately 2:1, the rated capacity ratio of the compressors is 0.88. 66
, 100% capacity control operation can be performed in four stages.

In addition, the compressors (xb) and (lc) have a duty section (
6), every time a certain period of time elapses, it is forcibly stopped regardless of the above pressure signal, and when restarting, four-stage capacity control operation of 0.3B and 66.100% is performed according to the above pressure signal. It has become.

[Problem that the invention seeks to solve]

Conventional refrigeration systems are configured as described above, so when the compressor is restarted during forced intermittent operation, if the refrigerant pressure is higher than the refrigerant pressure to be converged, that is, the capacity increase pressure setting value or higher (in the area of Since it takes a total of 9 minutes or more for the machine to start operating, it takes a long time to reach the target refrigerant pressure, which has the disadvantage that the freshness of the cooled material cannot be maintained.

This invention was made to solve the above-mentioned conventional problems. Even when the compressor is restarted during forced intermittent operation, it can quickly reach a predetermined pressure, and the freshness of the cooled material can be maintained. The purpose is to provide a refrigeration system that

[Means to solve the problem]

In this invention, the pressure detection section detects the refrigerant pressure on the low pressure side of the refrigeration cycle, generates a pressure detection signal, and sets the refrigerant pressure to be converged using the pressure setting section. a control unit that determines whether the signal is above or below the refrigerant pressure to be converged and generates a capacity control output signal for controlling the capacity of the refrigerator;
A refrigeration system is configured by providing a duty unit that controls forced intermittent operation of the compressor and a duty control unit that forcibly operates multiple compressors when the compressor is restarted after stopping during forced intermittent operation. It accomplishes its purpose.

[For production]

In the refrigeration system of the present invention, a plurality of compressors are forcibly operated when the duty section restarts the compressor after stopping it during forced intermittent operation. A predetermined pressure can be quickly reached at
The freshness of the object to be cooled is maintained.

[Embodiments of the invention]

FIG. 1 is a block diagram showing an embodiment of a refrigeration system according to the present invention, and the same parts as in FIG. 2 are designated by the same reference numerals. In the figure, (7) is a duty control section, and the duty section (6) controls the compressor (lb),
It has a function to forcibly operate a plurality of compressors (1b) and (IC) when restarting after stopping the compressor during forced intermittent operation of (lc).

Next, I will explain about one work. During forced intermittent operation of compression Y (lb), (1c) in duty section (6),
When restarting the compressor, if the refrigerant pressure is higher than the refrigerant pressure to be converged (i.e., in the region equal to or higher than the capacity increase pressure setting value), the duty control unit (7) will control the refrigerant pressure regardless of the pressure signal. Compression of multiple units 1m
(lb) and (lc) will be forced to operate.

In other words, as in the past, when the compressor is restarted during forced intermittent operation, the pressure detection section (3) detects the refrigerant pressure on the low pressure side of the refrigerant cycle and generates a pressure detection signal. Rather than controlling the capacity of the refrigerator by determining whether the signal is above or below the refrigerant pressure to be converged, which is the preset value in the above pressure setting g (4) (forcibly controlling the capacity of multiple units). Pressure @ti machine (lb).

(1c), the predetermined pressure can be quickly reached.

〔Effect of the invention〕

As explained above, in the refrigeration system of the present invention, the pressure detection section detects the refrigerant pressure on the low pressure side of the refrigeration cycle, generates a pressure detection signal, and the pressure setting section sets the refrigerant pressure to be converged. At the same time, a control unit that determines whether the pressure detection signal is above or below the refrigerant pressure to be converged and generates a capacity control output signal to control the capacity of the refrigerator, and a forced intermittent operation of the compressor. and a duty control unit that forcibly operates multiple compressors when the compressor is restarted after stopping during forced intermittent operation. In this case, a predetermined pressure can be quickly reached, the temperature of the object to be cooled becomes constant, and freshness is maintained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a refrigeration system according to the present invention, FIG. 2 is a block diagram showing a conventional refrigeration system, FIG. 8 is a diagram showing a region of refrigerant pressure on the low pressure side, and FIG. FIG. 3 is an explanatory diagram of capacity control operation of the refrigeration system in FIG. 2; In the figure, (1a) is a condenser, (1bX1c) is a compressor, (2a) to (2C) are coolers, (3) is a refrigeration circuit,
(3) is a pressure detection section, (4) is a pressure setting section, (5) is a control section, (6) is a duty section, and (7) is a duty system control section. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A plurality of compressors each having a suction pipe and a discharge pipe connected in parallel, a condenser that condenses and permeates the refrigerant discharged from these compressors, and a cooling system that evaporates and vaporizes the refrigerant sent out from the condenser. A refrigeration circuit in which pipes are connected in sequence to form a closed circuit, a pressure detection section that detects the refrigerant pressure on the low pressure side of this refrigeration circuit and generates a pressure detection signal according to this refrigerant pressure, a pressure setting unit that sets a convergence pressure value of the refrigerant pressure on the low pressure side; determines whether the pressure detection signal is greater than or equal to the convergence pressure value; generates an output signal based on the determination result; A control section that generates a capacity control output signal for controlling the capacity of the refrigerator based on the signal, a duty section that controls the forced intermittent operation of the compressor, and a A refrigeration system equipped with a duty control unit that forcibly operates multiple compressors when restarting.