JPH04353201A - compressor drive device - 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]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates primarily to a drive system for a screw compressor, and more particularly to a drive system in which a steam turbine is connected to the input side of the compressor, and the compressor is driven by the steam turbine.

0002

2. Description of the Related Art Conventionally, it has been proposed that a steam turbine is connected to the input side of a screw compressor used in a refrigeration system, and the compressor is driven by the steam turbine.

0003

[Problems to be Solved by the Invention] Incidentally, screw compressors are generally driven by electric motors, but the motor
In motor-driven compressors, a current limiting device is provided to prevent excessive stress from being applied to the compressor, which could lead to damage.

That is, the compressor is generally provided with a slide valve that enables its capacity to be controlled, and detects the outlet temperature of water or brine in the evaporator of the refrigeration system used as the compressor. The slide valve is operated to control its capacity.
When the motor current exceeds 1.05 times the rated value, the slide valve is forcibly closed to prevent excessive torque from being applied to the compressor.

However, if a steam turbine is used as the driving source for the compressor, or if a steam turbine is added to the motor to drive the compressor, the motor can be eliminated.
Moreover, even when used in combination, there is an advantage that the motor power can be reduced, but on the other hand, since the steam source of the steam turbine fluctuates frequently, the output of the steam turbine may exceed the permissible power of the compressor. There was a problem in that excessive torque was applied to the compressor and it could be damaged.

The present invention focuses on the fact that the shaft power Kw of the compressor is decisively controlled by the suction pressure and discharge pressure of the refrigerant, and limits the output of the steam turbine based on the suction pressure and discharge pressure. This prevents excessive torque from being applied to the compressor, and the purpose is to prevent excessive torque from being applied to the compressor while using a steam turbine.

[0007]

[Means for Solving the Problems] The present invention is a compressor drive device comprising a steam turbine 9 connected to the input side of a compressor 1, which detects the suction side pressure and the discharge side pressure of the compressor 1. A low-pressure pressure detector 18 and a high-pressure pressure detector 19 are provided, and shaft power data in the compressor 1 calculated based on the suction side pressure and the discharge side pressure is provided, and is detected by the respective detectors 18 and 19. When the shaft power value obtained by calculating the suction side pressure and the discharge side pressure is within the permissible power range of the shaft power set in advance, the evaporator turbine 9 is operated and outputs, and when the shaft power value exceeds the permissible power range, the A turbine output control means 20 for stopping the output of the evaporator turbine 9 is provided. Further, from the shaft power data of the compressor 1 calculated based on the suction side pressure and the discharge side pressure, an upper limit value of the suction side pressure and an upper limit value of the discharge side pressure are set in advance, and each of the detectors 18, Turbine output that operates when the suction side pressure and discharge side pressure detected by 19 are below the respective upper limit values to output the steam turbine 9, and stops the output of the steam turbine 9 when the respective upper limit values are exceeded. Control means 20 may also be provided.

The steam turbine 9 also includes a steam valve 10 for controlling operation and stop of the steam turbine 9, and the steam valve 10 serves as a turbine output control means 20.
It is preferable to open the shaft power of the compressor 1 to operate the steam turbine 9 when the shaft power of the compressor 1 is within the permissible power range, and to stop the operation of the steam turbine 9 when the shaft power exceeds the permissible power range.

Further, in the present invention, the steam turbine 9 is used as a drive source for the compressor 1, but it is also possible to use it together with the motor 7. , when the compressor 1 is driven by only the steam turbine 9 operating with the motor 7 powered off, and when the motor 7 is driven and the motor 7 and the steam turbine 9 are operated together, the compressor 1 is driven Compressor 1
There are cases where it is driven. Further, when used together with the motor 7, it is preferable that the turbine output shaft 12 of the steam turbine 9 and the drive shaft 13 of the motor 7 be connected via the clutch 8.

0010

[Operation] When the compressor 1 is driven using the steam turbine 9 as a drive source, when the shaft power of the compressor 1 is less than its allowable power (for example, 220 KW), the steam turbine 9
The compressor 1 is driven by the steam turbine 9. Also, when the suction side pressure and the discharge side pressure fluctuate and the shaft power exceeds its allowable power range, the output of the steam turbine 9 is changed. It stops.

Therefore, when the shaft power is below the allowable range, the steam turbine 9 can be outputted to drive the compressor 1, but when the shaft power exceeds the allowable range, the output of the steam turbine 9 is stopped. , it is possible to prevent excessive torque from being applied to the compressor 1.

Furthermore, the low pressure detector 18 and the high pressure detector 19 are used to detect the suction side and discharge side pressures, and to control the output from the steam turbine 9 so that excessive torque is not applied. Since the shaft power applied to the compressor 1 can be controlled close to the actual measured value,
Since the pressure detectors 18 and 19 can be of high reliability and widely used in refrigeration equipment, they can be used to detect the steam with high precision, at low cost, and with high reliability. The turbine 9 can be controlled, and damage to the compressor due to excessive torque can be effectively prevented.

[0013] Also, from the shaft power data of the compressor 1 calculated based on the suction side pressure and the discharge side pressure, an upper limit value of the suction side pressure and an upper limit value of the discharge side pressure are set in advance, and each of the above-mentioned detection When the suction side pressure and the discharge side pressure detected by the devices 18 and 19 are below the respective upper limit values, the steam turbine 9 operates and outputs the steam turbine 9, and when the respective upper limit values are exceeded, the output of the steam turbine 9 is stopped. By providing the turbine output control means 20, the shaft power is calculated based on the suction side pressure and the discharge side pressure detected by each of the detectors 18 and 19, and whether the shaft power is within a preset allowable power range or not. In other words, it is only necessary to determine whether the suction side pressure and the discharge side pressure are below the preset upper limit value or exceed the upper limit value, so the control system can be simplified. It can be made into something.

[0014] Also, the steam valve 10 is opened and closed to operate the steam turbine 9.
When controlling the output of the compressor 1, its operation can be stopped when the shaft power of the compressor 1 exceeds the allowable power range, so unnecessary operation of the steam turbine 9 can be eliminated and the durability of the entire system can be improved. It is.

Furthermore, when the steam turbine 9 and the electric motor 7 are connected to the input side of the compressor 1, as described above, when the shaft power of the compressor 1 exceeds the allowable range, the steam turbine 9 Since the output can be stopped, the motor power generated by the steam turbine 9 can be reduced, and damage to the compressor 1 due to excessive torque can also be prevented.

Even when the steam turbine 9 and the motor 7 are used together as described above, the compressor 1 can be driven only by the steam turbine 9 by turning off the power to the motor 7. In this case, the output of the steam turbine 9 is stopped, and the drive of the compressor 1 is also stopped. It is preferable to continue driving the machine 1.

Further, when the compressor 1 is driven using the motor 7 and the steam turbine 9 in combination, the output of the steam turbine 9 is stopped and the compressor 1 is driven only by the motor 7. Driven.

In either case, when the shaft power exceeds the allowable power, the output of the steam turbine 9 is stopped, so that excessive torque can be prevented from being applied to the compressor 1.

When used together with the motor 7, a clutch 8 may be provided between the steam turbine 9 and the motor 7 instead of opening and closing the steam valve 10 to control the operation of the steam turbine. It is also possible to control the output from the steam turbine 9 by turning on and off the clutch 8. In this case, the output from the steam turbine 9 can be controlled with good responsiveness. This makes it possible to more reliably prevent damage to the product.

[0020]

[Embodiment] The embodiment shown in Fig. 1 is a screw compressor 1.
This is a screw refrigeration system using an oil separator 2 and a condenser 3 connected to the discharge side of the compressor 1,
An evaporator 5 is connected to the outlet side of the condenser 3 via an expansion valve 4, and the outlet side of the evaporator 5 is connected to the suction side of the compressor 1 to circulate refrigerant as shown by the solid arrow. forming a cycle.

[0021] In Fig. 1, 6 is an oil cooler.

In the embodiment of FIG. 1, the compressor 1
An electric motor is installed on the input side of the screw rotor (not shown).
The steam turbine 9 is connected to the steam turbine 9 via the clutch 8 and the steam turbine 9 is connected to the steam turbine 9 through the clutch 8.
The power generated by the screw rotor is added to the power generated by the motor 7 to drive the screw rotor.

A steam pipe 11 having a steam valve 10 is connected to the input side of the steam turbine 9.
When the motor 7 is opened, the motor 7 is driven by steam supplied from a steam source (not shown), and the power taken from the output side of the turbine 9 is connected to the turbine drive shaft 12 via the clutch 8. is added to the drive shaft 13, and the screw rotor is driven by the total, and the output from the steam turbine 9 is stopped by disconnecting the clutch 8 or closing the steam valve 10, and the output from the steam turbine 9 is stopped. The screw rotor is driven only by the rotor 7.

The compressor 1 is provided with a slide valve (not shown) for controlling the capacity of the compressor 1 and a capacity control device 14 for controlling the slide valve. A temperature detector 16 for detecting the outlet temperature is provided in the connected water or brine outlet pipe 15, and the capacity control device 1 is controlled based on the outlet temperature detected by the temperature detector 16.
4 is operated to control the capacity of the compressor 1, and the motor 7 is provided with a current controller 17 to control the capacity of the compressor 1.
When the current of motor 7 becomes 1.05 times or more of the rated current,
The slide valve is forcibly closed.

On the other hand, low-pressure pressure detectors 18 are provided on the suction side and the discharge side of the compressor 1 to detect the suction side pressure,
A high-pressure pressure detector 19 for detecting the discharge side pressure is provided, and when the shaft power of the compressor 1 is within the allowable power range, the steam valve 10 is opened to operate the steam turbine 9, and the shaft power is A turbine output control means 20 is provided which closes the steam valve 10 and stops the operation of the steam turbine 9 when the power exceeds the allowable power range.

The shaft power of the compressor 1 is controlled by the suction side and discharge side pressures, and the shaft power is
In the case of 0KW, as shown in Figure 2, the discharge side pressure is 15
．． When the pressure is 2Kg/cm2 (saturation pressure equivalent to 41℃) and the suction side pressure is 4Kg/cm2 (saturation pressure equivalent to 0℃), the allowable power is 330KW.If these pressures exceed each of the above values, the allowable power is exceeded and the This results in excessive torque being applied to the compressor 1.

That is, in FIG. 2, the horizontal axis represents the evaporation temperature Ts.
The vertical axis shows the shaft power Kw, and the solid line shows the shaft power change when the condensation temperature Tc is 40°C, 41°C, and 45°C.

[0028] Accordingly, the turbine output control means 20
focuses on the fact that the shaft power of the compressor 1 is controlled by the suction side pressure and the discharge side pressure, and that the shaft power is determined by a function of these pressures, and calculates it in advance based on these suction side pressure and discharge side pressure. input the shaft power data of the compressor 1, input the suction side pressure and discharge side pressure detected by the respective detectors 18 and 19, calculate the shaft power by calculating these two pressures, If this shaft power is within a preset allowable power range as shown by the dotted line in FIG. 2, the shaft power operates to open the steam valve 10 and operate the steam turbine 9;
When the shaft power exceeds the permissible power range, the steam valve 10 is closed and the steam turbine 9 is stopped.

That is, when the shaft power is 330 KW as shown by the dotted line in FIG.
If s exceeds a temperature equivalent saturation pressure of 4.0 Kg/cm2 at 0°C, the shaft power of 330 KW will be exceeded, so in this case the steam valve 10 will close and the operation of the steam turbine 9 will stop. , and the condensation temperature Tc
When the temperature is 41° C., the steam valve 10 is opened and the steam turbine 9 is operated if the evaporation temperature Ts becomes lower than 0° C.

Note that even if the condensation temperature Tc is higher than the above-mentioned 41°C, the evaporation temperature Ts is lower than 0°C, or even if the evaporation temperature Ts is higher than 0°C, the condensation temperature Tc is higher than the above-mentioned 41°C.
℃, the shaft power 3 shown by the dotted line in Fig. 2
If the power does not exceed 30KW, the steam turbine 9 will be operated without closing the steam valve 10, but each of the above cases is rare under normal operating conditions.
The upper limit values of the suction side pressure and the discharge side pressure may be set in advance in consideration of normal operating conditions.

That is, in the example described above, the upper limit value of the discharge side pressure is set to, for example, 15.2 kg/cm2, and the upper limit value of the suction side pressure is set to, for example, 4 kg/cm2, and the discharge side pressure and The steam valve 10 is opened and the steam turbine 9 is operated only when the suction side pressure is below the preset predetermined value, that is, only in the shaded area in FIG. The steam valve 10 may be closed and the operation of the steam turbine 9 may be stopped when the shaft power exceeds the allowable power.

In this case, the turbine output means 20
This makes it possible to simplify the control system and prevent excessive torque exceeding the allowable power from being applied to the compressor 1.

Further, the turbine output control means 20 includes:
When the steam valve 10 is used, the steam valve 10 is an electromagnetic valve and is configured by a series circuit with each switch of the pressure detectors 18 and 19, and the clutch 8 is an electromagnetic clutch. It may also be controlled on/off.

As described above, the shaft power data of the compressor 1 calculated based on the suction side pressure and the discharge side pressure is input in advance, and the suction side pressure and When the shaft power obtained by calculating the discharge side pressure is within the preset permissible shaft power range, the steam turbine 9 is made to output, and when the permissible power range is exceeded, the output is stopped. The steam turbine 9 can be driven by outputting only within the allowable power range of the compressor 1, and the power of the steam turbine 9 can be used to reduce the power of the motor. However, it is possible to prevent the power from exceeding the allowable power and solve the problem of damage caused by excessive torque being applied to the compressor 1.

Moreover, whether or not to take in the output of the steam turbine 9 is determined by detecting the suction side pressure and the discharge side pressure using pressure detectors 18 and 19, which are widely used in refrigeration equipment and are highly reliable. However, since the control is based on each of these pressures, in other words, the torque is controlled based on the pressure, it is possible to control the torque close to the actual measured value, at a low cost, and with high accuracy and reliability. This allows for a high level of control.

In the embodiment described above, the steam turbine 9 and the electric motor 7 are connected to the input side of the compressor 1.
The compressor 1 may be driven using only the steam turbine 9 as the drive source.

Further, even when the steam turbine 9 and the motor 7 are used together as in the embodiment described above, the compressor 1 can be operated by the steam turbine 9 alone by turning off the power to the motor 7. It may also be driven.

In this case, when the output of the steam turbine 9 is stopped, the compressor 1 is also stopped, but in this case, the power to the motor 1 is turned on and the drive is switched to the motor 7 to start the compressor. The machine 1 may continue to be driven.

[0039]

Effects of the Invention The present invention provides a low-pressure pressure detector for detecting the suction side pressure and the discharge side pressure of the compressor 1 in a compressor drive device comprising a steam turbine 9 connected to the input side of the compressor 1. 18 and a high-pressure pressure detector 19, and the compressor 1 is calculated based on the suction side pressure and the discharge side pressure.
The respective detectors 18, 19 are provided with shaft power data at
When the shaft power value obtained by calculating the suction side pressure and discharge side pressure detected by is within the permissible power range of the shaft power set in advance, the evaporator turbine 9 is operated and outputs the evaporative turbine 9, exceeding the permissible power range. By providing the turbine output control means 20 that stops the output of the evaporative turbine 9 when the steam turbine 9 is in the When the range is exceeded, the output of the steam turbine 9 can be stopped, so that an excessive torque exceeding the allowable power is not applied to the compressor 1, and damage to the compressor 1 can be prevented.

Moreover, since the operation of the steam turbine 9 is controlled by checking the suction side and discharge side pressures using the pressure detectors 18 and 19, the accuracy of torque limitation can be improved, and safety can be ensured while wide range of operation can be controlled. Since the pressure detectors used in refrigeration equipment can be used, the entire system can be made simple and inexpensive, and the pressure detectors 18 and 19 are
Since it is widely used in refrigeration equipment and has high reliability, it is possible to improve the reliability of the entire equipment.

Further, from the shaft power data of the compressor 1 calculated based on the suction side pressure and the discharge side pressure, the upper limit value of the suction side pressure and the upper limit value of the discharge side pressure are set in advance, and each of the above detections is performed. When the suction side pressure and the discharge side pressure detected by the devices 18 and 19 are below the respective upper limit values, the steam turbine 9 operates and outputs the steam turbine 9, and when the respective upper limit values are exceeded, the output of the steam turbine 9 is stopped. Turbine output control means 20
By providing this, it is possible to simplify the control system of the turbine output control means 20 and prevent excessive torque exceeding the allowable power from being applied to the compressor 1.

Furthermore, if the turbine output control means 20 opens and closes the steam valve 10 to control the operation and stop of the steam turbine 9, unnecessary operation of the steam turbine 9 can be eliminated, and the The durability of the material itself can also be improved.

[0043] Also, along with the steam turbine 9, the electric motor 7
Similarly to the above, when the shaft power of the compressor 1 exceeds the allowable range, the output of the steam turbine 9 can be stopped. This makes it possible to prevent damage to the compressor 1 due to torque.

Furthermore, when used together with the motor 7, a clutch 8 is provided between the steam turbine 9 and the motor 7, and by turning on and off the clutch 8, the steam turbine 9 is turned on and off. When controlling the output of the steam turbine 9, the output from the steam turbine 9 can be controlled with good responsiveness, and damage to the compressor 1 can be more reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a piping system diagram of an entire refrigeration system to which an embodiment of the present invention is applied.

FIG. 2 is a shaft power characteristic diagram showing the relationship between the suction side pressure, the discharge side pressure, and the shaft power of the compressor in terms of the pressure-equivalent saturation temperature.

[Explanation of symbols]

1 Compressor 7 Motor 9 Steam turbine 10 Steam valve 18 Low pressure pressure detector 19 High pressure pressure detector 20 Turbine output control means

Claims (5)

[Claims] 1. A compressor drive device comprising a steam turbine 9 connected to the input side of the compressor 1, wherein the compressor 1
A low-pressure pressure detector 18 and a high-pressure pressure detector 19 are provided to detect the suction side pressure and the discharge side pressure of The evaporator turbine 9 operates when the shaft power value obtained by calculating the suction side pressure and the discharge side pressure detected by each of the detectors 18 and 19 is within a preset permissible shaft power range. A drive device for a compressor, which is provided with a turbine output control means 20 for controlling the output of the evaporator turbine 9 and stopping the output when the output exceeds the permissible power range. 2. A compressor drive device comprising a steam turbine 9 connected to the input side of the compressor 1, wherein the compressor 1
A low pressure detector 18 and a high pressure detector 19 are provided to detect the suction side pressure and discharge side pressure of the compressor 1, and from the shaft power data of the compressor 1 calculated based on the suction side pressure and the discharge side pressure , the upper limit value of the suction side pressure and the upper limit value of the discharge side pressure are set in advance, and when the suction side pressure and the discharge side pressure detected by each of the detectors 18 and 19 are below the respective upper limit values, the operation is performed. A compressor drive device that is provided with a turbine output control means 20 that causes a steam turbine 9 to output and stops the output of the steam turbine 9 when each of the upper limit values is exceeded. 3. The steam turbine 9 comprises:
The turbine output control means 20 opens the steam valve 10 to operate the steam turbine 9 when the shaft power of the compressor 1 is within the allowable power range, and The compressor drive device according to claim 1 or 2, wherein the compressor drive device is controlled to close and stop operation of the steam turbine when the range is exceeded. 4. The compressor drive device according to claim 1, wherein a steam turbine 9 and an electric motor 7 are connected to the input side of the compressor 1. 5. Turbine output shaft 12 of steam turbine 9
5. The compressor drive system according to claim 4, wherein the drive shaft 13 of the motor 7 is connected to the drive shaft 13 of the motor 7 via a clutch 8.