JPS603354Y2 - Refrigeration equipment - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a refrigeration system, and more particularly to a refrigeration system equipped with a crankcase heating device for a compressor, which can minimize the occurrence of foaming at the start of operation without causing liquid back-up, and improve operational efficiency.

[Prior Art] If the lubricating oil containing the refrigerant in the crankcase is at a low temperature when the compressor is started, the refrigerant will form, causing a compressor accident.

Due to the disadvantage of inducing [liquid compression],
Generally, a heater is installed in the crankcase to maintain the oil temperature in the crankcase at a predetermined value above the summer ambient temperature, for example 30 to 60 degrees Celsius, after the refrigerator has stopped.
Continuously energizing the compressor while it is stopped consumes power unnecessarily and increases running costs, making it uneconomical. There is a system in which a program timer is used to energize a heater provided in the crankcase for a certain period of time prior to starting the compressor.

[Problem that the invention attempts to solve]

In the case of a heating device using one type of program timer as described above, there are many variable conditions to determine the appropriate heating amount of the heater, such as the installation area and location of the refrigeration device, and the ambient temperature, and it is necessary to determine the conditions accurately. Since it is difficult to set the energization time, it is difficult to set the energization time sufficiently to reliably reduce running costs. Therefore, the present invention addresses this fact and attempts to improve economical operation and reliability of the device by automatically controlling the crankcase heater to the shortest heating time that suits various ambient conditions. It is something to do.

[Means to solve the problem]

As clearly shown in FIG. 1, the present invention provides a refrigeration system with a heater 5 disposed in the crankcase portion 1a of the compressor 1, a timer 8 for setting the operation start time, and a crankcase portion of the refrigeration system. An oil temperature detector 6 for detecting the lubricating oil temperature TO in the tank a, a temperature detector 7 for detecting the compressor ambient temperature TM, a remaining stop time calculation means a, a reference value storage means port, and a heater heating time. The calculation means is provided with a comparison means 2 and a heater energization start means E. Therefore, the remaining stop time calculation means 1 subtracts the elapsed time T after the timer 8 is set from the initial remaining stop time Ts up to the operation start time when the timer 8 is set, and calculates the actual remaining stop time T.
It has a function to calculate T. Next, the reference value storage means port has a function of storing and reading out the heat radiation amount of the crankcase portion 1a, the heat capacity of the crankcase portion 1a and the lubricating oil, and the heating amount of the heater 5 as a reference at any time. On the other hand, the heater heating time calculation means c calculates the oil temperature of the lubricating oil based on the output from the oil temperature detector 6, the output from the temperature detector 7, and the output based on each stored information from the reference value storage means port. It has an arithmetic function to calculate the heating time TR of the heater 5 necessary to raise the temperature to a predetermined value. Next, the comparison means 2 compares the actual remaining stop time TT calculated by the remaining stop time calculation means 1 with the heater heating time TR calculated by the heater heating time calculation means 1, and calculates the actual remaining stop time. It has a function of outputting a signal when TT becomes less than the heater heating time. Further, the heater energization start means E has a function of being activated and energizing the heater 5 upon receiving the output signal of the comparison means 2.

[Effect]

The present invention having the above-mentioned means calculates the required heating time TR of the heater 5 from various conditions necessary for determining the heating amount of the heater 5, and calculates the time when the actual remaining stop time TT matches. By energizing the heater 5, the heating can be performed with just the right amount of electricity and proper heating operation can be performed.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 is a schematic circuit diagram of a refrigeration system according to an embodiment of the present invention, in which 1 is a compressor, 2 is a condenser, 3 is an expansion valve, and 4 is an evaporator. is connected to a known circulation circuit via refrigerant piping. For example, an electric heater 5 is attached to the crankcase portion 1a of the casing of the compressor 1 so as to surround the casing, and the electric heater 5 heats low-pressure refrigerant mixed with lubricating oil to a predetermined oil temperature. In addition, the temperature of the lubricating oil in the crankcase portion 1a is T. The compressor 1 has a built-in temperature detector 6 that detects the ambient temperature TM and converts it into an electrical signal.On the other hand, a temperature detector 7 that detects the ambient temperature TM and converts it into an electrical signal is installed outside the compressor 1. It is located close to. The reason for providing both detectors 6 and 7 in this way is that the amount of refrigerant dissolved in the oil changes depending on the oil temperature and pressure.

[4th
This is because the amount of refrigerant dissolved in the oil cannot be confirmed unless the oil temperature and pressure are detected. In addition, since the pressure inside the crankcase part a is approximately between the saturation pressure of the refrigerant corresponding to the ambient temperature of the compressor 1,
In this embodiment, the ambient temperature is detected. Both detectors 6, 7, together with a timer 8, are connected to a signal input of a controller 9 and form input elements, while the electric heater 5 is connected to an output of the controller 9. As will be made clear from the explanation of the operation described below, the controller 9 has a known simple electronic computer as an element, and the electronic computer is composed of an input device, a storage device, an arithmetic device, and an output device. are doing. First, the storage device consists of a reference value storage means port in which the heat dissipation amount and heat capacity of the crankcase portion 1a, the heat capacity of the lubricating oil, and the heating amount of the electric heater 5, which serve as a reference, can be written and read out at any time. Accurate values for each piece of information must be calculated at the time of design. The input device is the output from the oil temperature detector 6 and the temperature detector 7, each memory information from the reference value storage means port, and the initial remaining stop time Ts until the operation start time obtained by setting in advance with the timer 8. and the receiver has an input terminal portion that receives the input terminal.
It is formed to transmit each of these inputs to the next stage arithmetic unit. Next, the arithmetic device transmits the timer 8 to a heater heating time calculation means that calculates the heating time TR of the electric heater 5 necessary to raise the lubricating oil temperature to a predetermined value based on the input from the input device. Remaining stop time calculation means A for calculating the actual remaining stop time T by subtracting the elapsed time T after setting from the initial remaining stop time at the time of setting, and the actual remaining stop time T being less than or equal to the heater heating time TR. and a comparing means 2 which outputs a signal when the signal is reached. On the other hand, the output device is formed of heater energization starting means E, such as a power transistor, which receives the output signal from the comparing means 2 and energizes the electric heater 5. The operating mode of the controller 9 having the above configuration will be explained below with reference to FIGS. 2 and 3.
After that, the timer 8 is operated to set 11 the initial remaining stop time T until the scheduled start time of operation of the refrigeration system. The lubricating oil temperature TO and the ambient temperature TM detected by both the detectors 6 and 7 are transmitted to the arithmetic unit via the input device. On the other hand, the reference value storage means port is provided with the crank case portion 1.
The heat capacity and heat dissipation amount of a, the heat capacity of the lubricating oil, and the heating amount of the heater 5 are stored in advance as information, and when the operation command 10 is issued, the information is input to the arithmetic unit. The calculation device calculates the lubricating oil temperature T. , ambient temperature TM and each of the above-mentioned stored information, the oil temperature in the crankcase is determined to be a temperature at which the compressor will not be damaged due to a large amount of foaming occurring when the compressor is started, that is, 30°C, which corresponds to the ambient temperature in summer. The heating amount of the heater 5 necessary to maintain the temperature at a predetermined value of, for example, 40° C. from 60° C. to 60° C. is calculated 12 by using the heater heating time calculating means as a value TR in units of time. At the same time, the arithmetic unit calculates the actual remaining stop time TT from the present time to the initial remaining stop time T at the driving start time, that is, TT=TST, using the remaining stop time calculation means 13. The time T is the time that has already passed since the setting. These two calculation results are compared 14 using comparison means 2, and TR=TT
If so, the heater energization start means E of the output device is activated to energize the heater 5, while if T3<T, the heater 5 is not energized. By doing so, the crankcase heater 5 starts to be energized at a predetermined time calculated backward from the operation start time,
Appropriate heating operation can be performed that does not cause power loss and also prevents or minimizes the forming phenomenon during operation. Hereinafter, a comparison of the amount of forming at the time of starting the compressor with and without the crankcase heater will be described with reference to FIG. Note that Freon 22 is used as the refrigerant and Atmos oil is used as the lubricant.

[Suniso 4GS equivalent] was used. Assume that the compressor is stopped at an ambient temperature of 10° C., and that the refrigeration system has a saturation pressure of kg/cIl and high and low pressures are balanced. For several minutes after the compressor 1 is started, the pressure is about 1 to 1.5 ko/cft, which is lower than the low pressure of 4 to 5 ko/cft under steady load when the ambient temperature is 10°C.
kp/cIt As the low pressure further decreases, the low pressure is approximately 2.
5-3 will be 91c7ft. When the crankcase heater is not used, the oil temperature is equal to the ambient temperature, so the oil temperature [10℃] and the pressure cuff kg/C1ft.
Approximately 26% of Freon 22 is dissolved in the oil. At this time, compressor 1 starts and the low pressure is 2.5 kg/c71
! When the solubility of Freon 22 decreases to 10%, the difference of 16% results in foaming. However, by energizing the crankcase heater and increasing the oil temperature by 4.
If the oil temperature has been raised to 0℃, the oil temperature should be changed as above.

[40℃
] and low temperature 7kg1crl, Freon 22 is 12 in oil.
% dissolved, but at startup it drops to about 4%, and the difference is 8% for forming. Therefore, it can be seen that the amount of freon 22 to be formed is smaller when the crankcase heater is used. Furthermore, as is clear from Fig. 4, even if the saturation pressure in the crankcase of the compressor 1 is constant, the amount of refrigerant dissolved in the oil differs if the oil temperature changes; While it gradually decreases after the compressor 1 stops, the saturation pressure in the crankcase of the compressor 1 reaches a balance between high and low pressures within a few minutes after the compressor 1 stops, and becomes approximately equal to the saturation pressure corresponding to the ambient temperature of the compressor 1. Therefore, the oil temperature and the temperature corresponding to the saturation pressure are not the same, and in addition, the ambient temperature differs during the severe cold season and the middle season, and the rate of heat radiation from the oil to the surroundings also differs. By sensing the two ambient temperatures, the amount of refrigerant dissolved in the oil can be determined, and this input signal allows determining the appropriate amount of heating and required heating time. As is clear from Figure 4, it is preferable to keep the oil temperature high within a range that does not cause burnout of the compressor as this will reduce foaming, but it is important to uniformly determine the oil temperature depending on the type of compressor and equipment system. Although it is difficult to
It is desirable to raise the oil temperature to 0°C.

[Effect of the idea]

As described in detail above, in the present invention, prior to operation of the refrigeration equipment, electricity is supplied to the heater 5 of the crankcase portion 1a of the compressor 1 for the minimum necessary time calculated backward from the operation start time, and the forming process is performed when the compressor 1 is started. The temperature of the lubricating oil is raised to a temperature that minimizes the occurrence of foaming and does not cause damage to the compressor, but also does not cause overheating, so the degree to which the refrigerant in the lubricating oil forms is limited. The amount of power is reduced to a minimum, and there is no power loss at all, improving economic efficiency and increasing safety. Furthermore, it increases the reliability of preventing a large amount of forming from occurring at the start of operation, and also prevents deterioration of lubricating oil performance due to overheating, which significantly improves the reliability of refrigeration equipment. The idea was a great refrigeration device with great practical value.

[Brief explanation of the drawing]

Fig. 1 is a block diagram clearly showing the configuration of the present invention, Fig. 2 is a device circuit diagram of a refrigeration system according to an embodiment of the present invention, and Fig. 3 is an explanation of the operation of the controller in the refrigeration system shown in Fig. 2. The procedure diagram, FIG. 4, is a temperature-pressure-solubility curve of Freon 22 to explain the prevention of forming. 1...Compressor, 1a...Crankcase, 5...
Heater, 6...Oil temperature detector, 7...Temperature detector, 8
・・・Timer, A... Remaining stop time calculation means, 口...
Reference value storage means, C... Heater heating time calculation means, II... Comparison means, E... Heater energization start means, T...
- Elapsed time, T7...compressor ambient temperature, To...lubricating oil temperature, TR...heater heating time, TT...actual remaining stop time.

Claims (1)

[Scope of utility model registration request] A heater 5 disposed in the crankcase portion 1a of a compressor 1 in a refrigeration system, a timer 8 for setting an operation start time, and a timer 8 for setting an operation start time from the initial remaining stop time Ts until the operation start time when the timer 8 is set. remaining stop time calculation means (a) for calculating the actual remaining stop time (TA) by subtracting the elapsed time (T) of
An oil temperature detector 6 that detects the temperature of The lubricating oil is determined by the reference value storage means port for storing the heating amount of the heater 5, the output from the oil temperature detector 6, the output from the temperature sensor 7, and the output from the reference value storage means port. Heater heating time calculation means c which calculates the heating time TR of the heater 5 necessary to raise the temperature to a predetermined value; the actual remaining stop time T calculated by the remaining stop time calculation means b; Comparing means 2 that compares the heater heating time TR calculated by the heater heating time calculating means and outputs a signal when the actual remaining stop time TT becomes equal to or less than the heater heating time TR; The heater 5 receives the output signal of
1. A refrigeration system comprising: heater energization starting means (e) for energizing the heater.