JPS5838950Y2 - Turbo chiller safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a centrifugal refrigerator, and more particularly to the configuration of a safety device that can eliminate the adverse effects of the presence of non-condensable gas on the refrigerator and the reduction in operating efficiency due to refrigerant leakage.

If there is a non-condensable gas such as air in the centrifugal chiller equipment, the heat transfer performance will deteriorate and the capacity of the chiller will decrease.
In addition, moisture in the air that leaks together with the invading air causes corrosion of the equipment.

Therefore, an automatic air extraction device as shown in FIG. 1 is provided for the turbo chiller and is in practical use.

This device consists of a condenser 1 and a bleed tank 4 connected to an evaporator 3.
When the internal pressure of the bleed tank 4 is higher than the atmospheric pressure and the differential pressure with the condensation pressure is below a set value, the non-condensable gas accumulated in the bleed tank 4 is forcibly extracted into the atmosphere through the bleed pipe 2. This air extraction operation is performed as necessary during operation of the refrigerator.

However, it is inevitable that the extracted non-condensable gas will contain a small amount of refrigerant, and as the frequency of automatic extraction increases, the amount of leaked refrigerant will increase, causing the refrigerant in the device to As a result, efficient operation becomes impossible.

It is also undesirable because it causes rust inside the refrigerator.

The present invention was developed in response to this situation, and includes an automatic air extraction device that performs forced extraction during refrigeration operation when the amount of noncondensable gas trapped reaches a certain limit, and an automatic air extraction device that performs forced extraction during refrigeration operation. It is characterized by a configuration in which the centrifugal chiller is equipped with a root stone device that detects the operating frequency of the device within a set time and issues a display or alarm when the operating frequency reaches a predetermined value.

The specific contents of the present invention having these features will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a centrifugal chiller according to the present invention. The discharged refrigerant gas is condensed and liquefied in the condenser 1, then depressurized and expanded in a decompression device (not shown) in the refrigerant storage chamber 2, and then transferred to the evaporator 3.
The refrigerant is vaporized and sucked into the compressor, and this refrigerant circulation is repeated.

This refrigerator is equipped with an automatic air bleed device as an element of the safety device, and numeral 4 is an air bleed tank which forms a sealed container, and is equipped with a cooling coil 5 and a solenoid valve 9 interposed therein. A bleed pipe 8 is provided in communication with the upper part of the tank.

The bleed tank 4 communicates with the condenser 1 via a gas pipe 12 hermetically connected to the side wall, and communicates with the evaporator 3 via a liquid pipe 13 hermetically connected to the bottom wall. A float valve 7 is interposed at the connection portion of.

Further, the cooling coil 5 has its inlet side connected to the refrigerant reservoir chamber 2 through a pipe 14, and its outlet side connected to the refrigerant reservoir chamber 2 through a pipe 15.
The refrigerant liquid is connected to the evaporator 3 by the evaporator 3, and the refrigerant liquid, which has been depressurized by the pressure reducing device after flowing out from the condenser, is made to flow to the cooling coil 5.

Reference numeral 16 denotes a tank pressure detection tube drawn out from the bleed tank 4, which connects the low pressure sides of the low pressure switch 10 and the differential pressure switch 11 to the tank pressure detection tube 9;
is a condensation pressure detection tube branched from the gas pipe 12, and the high pressure side of the differential pressure switch 11 is connected to the condensation pressure detection tube 1.
7 is connected.

The low pressure switch 10 detects the internal pressure of the gas bleed tank 4 and issues an electric signal when it becomes higher than atmospheric pressure by 0.1 kg/cm, while the differential pressure switch 11 detects the pressure within the gas pipe 12, that is, condensation. Comparing the pressure with the pressure inside the bleed tank 4, the condensation pressure inside the car bleed tank 4 pressure≦0.15 kg/
It is designed to emit electrical signals under cm2 conditions.

Next, to explain the operation of the above-mentioned air extraction device, the condenser 1
A part of the refrigerant gas is continuously collected into the bleed tank 4 through the gas pipe 12 from the upper part of the tank.

This refrigerant gas is cooled in the cooling coil 5 by exchanging heat with the evaporating refrigerant at the same temperature (pressure) as the evaporator 3, and the moisture and condensed refrigerant are separated into the tank 4.
While it accumulates at the bottom, non-condensable gases such as air are separated and evacuated to the upper part of the tank 4.

When the condensed refrigerant reaches a considerable amount, the float valve 7 acts to drain the liquid pipe 1.
3 to the evaporator 3, while the water is discharged to the outside of the tank 4 by a manually opened valve 6.

However, when the amount of non-condensable gas in the bleed tank 4 becomes large, the internal pressure of the tank 4 does not drop, and the differential pressure switch 11 reaches the set condition and issues a signal.

Also, if the internal pressure of the tank 4 rises and becomes higher than atmospheric pressure,
The low pressure switch 10 issues a signal when the set condition is reached.

Only when these two signals coexist, the solenoid valve 9 is opened, and the non-condensable gas (mostly air) present in the upper part of the bleed tank 4 is forcibly removed.

In this way, the non-condensable gas is automatically extracted, and the device of the present invention has the above-mentioned automatic extraction device and a root stone device as an element, and the root stone device is used together with the electric circuit section of the automatic gas extraction device. This will be explained with reference to FIG.

The above-mentioned root stone device consists of a counter 18, a timer 19, a buzzer 20-1, an indicator light 20-2, and an auxiliary relay 21, while the electric circuit section of the automatic bleed device includes a solenoid 9S of a solenoid valve 9 and an output contact of a low pressure switch 10. 10 a and
It consists of an output contact 11a of the differential pressure switch 11.

Then, the solenoid 9S is connected to the output contacts 10a and 11a.
By connecting the refrigeration operation command contact 22 and the operating power supply in series, when both switches 10 and 11 are activated during refrigeration operation, the solenoid valve 9 is opened by the solenoid 9S excitation, and the bleed is interrupted. It will be done.

The counter 18 has a drive section connected in parallel to the solenoid 9S, and a reset coil is operated via one contact 23b of the double reset switch 23 and the time-limited release/instantaneous return contact 19a of the timer 19 in series. It is connected to a power source, and counts the number of times the solenoid 9S is energized, that is, the number of times the valve is opened, and when this reaches a predetermined number of times, for example, five times, it closes the output contact 18a, and also closes the output contact 18a.
When at least one of the contacts 9a is opened, it is reset, the output contact 18a is opened, and the count is started from the first time.

On the other hand, the timer 19 connects the contact 19a with the instantaneous opening/
The refrigeration operation command contact 22 is connected to the drive unit in series. It is connected between the operation power supply through.

Next, the buzzer 20-1 and the indicator light 20-2 are in a parallel relationship, and are connected between the operating power source through the contact 19b of the timer 18 and the output contact 18a of the counter 18 in series.

The auxiliary relay 21 also includes a buzzer 20-1 and an indicator light 2.
Self-holding contact 21 with a coil connected in parallel to 0-2
A and the other contact 23a of the reset switch are connected in series to the operating power source.

Next, the operation of the root stone device will be described. Simultaneously with the start of operation of the refrigerator, the timer 19 measures time and adds up the operating time.

When the set time is reached, contact 19a is temporarily opened, contact 19b is temporarily closed, and the counter 18 is switched to contact 19.
Reset by a.

When the counter 18 counts that the automatic air extraction operation has been performed a predetermined number of times before the timer 19 reaches the set time, the output contact 18a closes, so when the set time is reached, the buzzer 20-1 and indicator light 20- 2 is activated, and this activation is maintained by the auxiliary relay 21.

Therefore, automatic air extraction is performed frequently to accurately detect that a considerable amount of refrigerant is leaking.

This discount can be restored by operating the reset switch 23a.

If the frequency of automatic air extraction operation is low during the set time of the timer 19, the counter 18 is reset by the contact 19a of the timer 19 and starts counting again from the beginning, and the root stone device does not operate at full heat.

In this way, the root system will reliably notify the operator that a large refrigerant leak is likely to occur, and can provide a warning to the operator to take appropriate action.

As is clear from the above description, the device of the present invention opens the solenoid valve 9 of the bleed pipe 8 connected to the bleed tank 4 when the limit amount of non-condensable gas accumulates in the bleed tank 4 connected to the condenser 1. It consists of an automatic extraction device that extracts condensed gas, and a root device that detects the opening frequency of the solenoid valve 9 within a set time and displays and issues an alarm when the opening frequency reaches a predetermined number. This not only eliminates the inconvenience caused by the presence of non-condensable gas in the refrigeration system, but also makes it easy to determine whether or not there is a refrigerant leak, thereby preventing a decrease in operating efficiency and the risk of rust due to refrigerant loss. It is a highly reliable device as a safety device for centrifugal chillers, and has great practical value.

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram of a centrifugal refrigerator according to an embodiment of the apparatus of the present invention, and FIG. 2 is an exploded view of the main parts of the electric circuit of the refrigerator shown in FIG. 1... Condenser, 4... Bleeding tank, 8
... Bleed pipe, 9 ... Solenoid valve, 18 ...
... Counter, 19 ... Timer 20-
1...Buzzer, 20-2...Indicator light.

Claims (1)

[Scope of utility model registration request] When the limit amount of non-condensable gas accumulates in the bleed tank 4 connected to the condenser 1, the solenoid valve 9 of the bleed pipe 8 connected to the bleed tank 4
an automatic extraction device that opens the valve to extract noncondensable gas; and a root stone device that detects the opening frequency of the electromagnetic valve 9 within a set time and issues a display, alarm, etc. when the opening frequency reaches a predetermined value. A safety device for a centrifugal chiller, comprising: