JPS5989960A - Preventive device for starting during suspension of air conditioner - 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 directed to prevention of so-called sleep startup in a refrigeration cycle in which a compressor, a four-way valve, a heat exchanger expansion mechanism on the non-use side, a heat exchanger on the use side, etc. are sequentially connected. Regarding equipment.

Conventional configurations and their problems Conventionally, in heat pump type air conditioners or chilling units, etc., in order to prevent so-called sleep startup, the compressor is provided with a crankcase heater, and the first
It was operated by a circuit as shown in the figure. Namely, 1 is the three-phase power supply, 2 is the main power switch, 3 is the A contact of relay 9, 4 is the compressor, and 5 is the bottom of the compressor body, which is used to heat oil to prevent sleep startup. One end of this crankcase heater 5 is a crankcase heater.
It is connected to the R phase of the three-phase power supply 1 via the B contact 6 of the relay 9, and the other end of the crank case heater 5 is connected to the T phase of the three-phase power supply 1. 7 is the power supply on the operation circuit side, 8 is the operation switch, and the relay is connected to the power supply 7 via the operation switch 8.
It is connected to the.

For example, when the main power switch 2 is turned on to start operation after the refrigeration equipment has been stopped for a long period of time, and the operation switch 8 is turned on immediately after that, the relay 9 is energized and the A contact 3 is turned on. Then, the B contact 6 is disconnected, the power to the crankcase heater 5 is cut off, and even though the oil in the compressor can is not heated, the compressor 4 is operated and oil is discharged from the compressor discharge pipe. It is discharged and circulates within the refrigeration cycle, causing a reduction in the refrigeration effect or seizure of the shaft of the rotating part of the compressor. In addition, due to the foaming, the liquid is compressed and cavitation occurs in the discharge valve, which may lead to accidents such as valve cracking. That is, if the operation switch 8 is turned on a short time after the main power switch 2 is turned on, the compressor 4 is immediately operated without heating the oil, which has the drawback of causing the above-mentioned accident. Was.

Purpose of the Invention The present invention is to energize a crankcase wrapped around a compressor and prevent the compressor from operating until a certain predetermined time has elapsed, thereby preventing oil forming from occurring. With the goal.

Structure of the Invention The present invention provides a main power switch from a power source, a crankcase heater wrapped around the compressor, and a temperature difference switch connected to the operating circuit in the middle of a circuit connected to the compressor via a relay contact. The main body and the temperature difference switch main body are connected to an oil temperature sensor that senses the oil temperature at the bottom of the compressor can and an outside air temperature sensor that senses the outside air temperature, and the difference in temperature detected by these two sensors is connected to the oil temperature sensor that senses the oil temperature at the bottom of the compressor can. The compressor is operated by

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1 is a three-phase power supply, 2 is a manual main power switch, and 3 is a relay 1
4 is the A contact, 4 is the compressor, 5 is the crankcase heater wrapped below the compressor can, and one end of the crankcase heater 5 is connected to the R of the three-phase power supply 1 via the B contact 6 of the relay 14. The other end of the crankcase heater 5 is connected to the T phase of the three-phase power supply 1. Reference numeral 7 indicates an operating power source for the circuit on the operating side, 8 indicates an operation switch, and 9 indicates a temperature difference switch. 11, and is also connected to an outside air temperature sensor 13 via a lead wire 12. When the temperature difference between these two sensors reaches a predetermined temperature difference, the temperature difference switch 9 is turned on. 1-14 is the temperature difference switch 9 and the operation switch,
In the above configuration, when the main power switch 2 is turned on, the crankcase heater 6 is energized via the B contact 6 of the relay 14. As a result of this energization, the oil at the bottom of the compressor body begins to heat up, and the oil temperature sensor 11 senses this temperature, and the difference between this temperature and the outside air temperature sensed by the outside air temperature sensor 13 is a predetermined temperature difference. When the temperature difference switch 9 is turned on, the relay 14 is energized, the A contact 3 is closed, the B contact 6 is opened, and the compressor 4 starts operating. The heater 6 starts to be energized, heats the oil, and compares the oil temperature detected by the oil temperature sensor 11 with the oil temperature sensor 11.
The compressor 4 is not operated until a predetermined temperature difference occurs between the outside air temperature and the outside air temperature sensed in step 3. Also, if the temperature difference becomes less than the predetermined temperature difference during operation, there is a strong possibility that the evaporative refrigerant on the suction pipe side is not heated and the liquid backs up. Since the oil is diluted and easily discharged into the refrigeration cycle, and the low viscosity oil is likely to cause shaft burning, the temperature difference switch 9 should be turned OFF and the A contact 3 of the relay 14 should be opened. , the B contact 6 is closed to stop the compressor 4, and the crankcase heater 5 is energized again to heat it until it reaches a predetermined temperature difference or higher, and then restarted.

Effects of the Invention As described above, the air conditioner sleep start prevention device of the present invention has the following advantages:
A temperature difference switch is provided on the operation circuit side, and this temperature difference switch is connected to an oil temperature sensor for detecting the oil temperature at the bottom of the compressor body and an outside air temperature sensor for sensing outside air temperature. When the difference between the oil temperature and the outside temperature detected by the sensor exceeds a predetermined temperature difference, the compressor is enabled to operate. The compressor will not be operated unless there is a temperature difference, and the oil at the bottom of the compressor will be operated at a temperature above a certain level, thus preventing oil forming. In other words, the amount of oil discharged from the compressor becomes extremely small, and the oil is no longer discharged temporarily. Therefore, the lubrication inside the compressor prevents seizure due to lack of oil film and cavitation due to liquid compression. This has practical effects such as preventing the occurrence of air pollution, prolonging the life of the compressor, and preventing a decrease in the capacity of the refrigeration cycle.

[Brief explanation of the drawing]

FIG. 1 is an operating circuit diagram of a conventional air conditioner sleep start prevention device, and FIG. 2 is an operation circuit diagram of an air conditioner sleep start prevention device according to the present invention. 1...Three-phase power supply (power supply), 3...A contact, 4...Compressor, 5...Crankcase heater, 6...・ B contact point, Y ・ ・ ・ ・ ・ ・ ・ Operation electronia, 9 ・ ・ ・ ・ ・ Different temperature switch, 11 ・ ・ ・ ・ Oil temperature Se, Sir, 13 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 14 ······relay.

Claims (1)

[Claims] A crankcase heater is wrapped around the compressor of a refrigeration cycle in which a compressor, a four-way valve, a heat exchanger on the non-use side, a heat exchanger on the expansion mechanism use side, etc. are connected in sequence, and the compressor is connected to the compressor via the A contact of the relay. and connect the crankcase heater to the power source via the B contact of the relay, and the relay detects the oil temperature at the bottom of the compressor can body, which is detected by the oil temperature sensor, and the outside air temperature sensor. A sleep-start prevention device for an air conditioner connected to an operating power source via a temperature difference switch that closes when the difference between the outside temperature and the outside temperature exceeds a predetermined temperature difference.