Surging prediction device for a centrifugal compressor

• US 5,095,714 A
• Filed: 12/21/1990
• Issued: 03/17/1992
• Est. Priority Date: 12/25/1989
• Status: Expired due to Term

• Current Assignee: Daikin Industries Ltd
• Original Assignee: Daikin Industries Ltd
• Inventors: Oka, Tetsuo, Adachi, Yasunori
• Primary Examiner(s): TAPOLCAI, WILLIAM E
• Application Number:
  US07/631,459
• Time in Patent Office: 452 Days
• Field of Search: 415/47-49, 415/17, 415/129, 415/130, 417/295, 62/197
• US Class Current: 62/197
• CPC Class Codes: F04D 27/001 Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring
• CPC Class Codes: F05D 2270/3015 differential pressure
• CPC Class Codes: F25B 49/022 Compressor control arrangements

Abstract

A surging prediction device for a centrifugal compressor has a differential pressure detector and a controller. The detector detects a differential pressure between a hub side pressure in the vicinity of an inlet or a diffuser in the centrifugal compressor and a shroud side presser in the vicinity of the inlet of the diffuser. The controller compares the detected differential pressure from the detector with a set differential pressure beforehand set so as to be lower than a surging differential pressure between the hub side pressure and the shroud side pressure at an occurrence time of surging, and outputs a surging signal predicting an occurrence of surging when the detected differential pressure becomes higher than the set differential pressure.

Claims

1. In a surging prediction device for a centrifugal compressor including an impeller mounted on a shaft and a housing which accommodates the impeller and a diffuser formed so that an inlet of the diffuser confronts an outer periphery of the impeller, the surging prediction device for a centrifugal compressor comprising:

a hub side pressure detection means for detecting a hub side pressure which is a fluid pressure on a first wall of the diffuser in one direction of the shaft in the vicinity of the inlet of the diffuser;

a shroud side pressure detection means for detecting a shroud side pressure which is a fluid pressure on a second wall of the diffuser in the other direction of the shaft in the vicinity of the inlet of the diffuser;

a differential pressure detection means which is connected to the hub side pressure detection means and the shroud side pressure detection means, and detects a differential pressure therebetween; and

a control means which receives a signal representing the detected differential pressure from the differential pressure detection means, and compares the detected differential pressure with a set differential pressure beforehand set so as to be lower than a surging differential pressure between the hub side pressure and the shroud side pressure at an occurrence time of surging, and outputs a surging signal predicting an occurrence of surging when the detected differential pressure becomes higher than the set differential pressure.

2. The surging prediction device for a centrifugal compressor in accordance with claim 1, wherein the hub side pressure detection means is a conduit passage opened on the first wall of the diffuser, and the shroud side pressure detection means is a conduit passage opened on the second wall of the diffuser, and the differential pressure detection means is a differential pressure detector connected to both the conduit passages.

3. The surging prediction device for a centrifugal compressor in accordance with claim 1, wherein the hub side pressure detection means is a pressure sensor to detect a pressure on the first wall of the diffuser, and the shroud side pressure detection means is a pressure sensor to detect a pressure on the second wall of the diffuser, and the differential pressure detection means is a differential pressure detector electrically connected to both the pressure sensors.

4. In a surging prediction device for a centrifugal compressor including an impeller mounted on a shaft and a housing which accommodates the impeller and a diffuser formed so that an inlet of the diffuser confronts an outer periphery of the impeller, the surging prediction device for a centrifugal compressor comprising:

a hub side pressure detection means for detecting a hub side pressure which is a fluid pressure on a first wall of the diffuser in one direction of the shaft in the vicinity of the inlet of the diffuser;

a shroud side pressure detection means for detecting a shroud side pressure which is a fluid pressure on a second wall of the diffuser in the other direction of the shaft in the vicinity of the inlet of the diffuser;

a differential pressure detection means which is connected to the hub side pressure detection means and the shroud side pressure detection means, and detects a differential pressure therebetween;

a control means which receives a signal representing the detected differential pressure from the differential pressure detection means, and calculates a pressure gradient with respect to time in the detected differential pressure, and calculates predicted occurrence time of surging based on the pressure gradient, the detected differential pressure and a surging differential pressure between the hub side pressure and the shroud side pressure which is beforehand detected at an occurrence time of surging, and outputs a signal representing the predicted occurrence time of surging; and

a display means which receives a signal representing the predicted occurrence time of surging from the control means and displays the predicted occurrence time of surging.

5. In a surging prevention device for a centrifugal compressor including an impeller mounted on a shaft, a housing which accommodates the impeller and a diffuser formed so that an inlet of the diffuser confronts the outer periphery of the impeller, suction vanes and a vane opening adjustment mechanism for adjusting opening of the suction vanes, the surging prevention device for a centrifugal compressor comprising:

a hub side pressure detection means for detecting a hub side pressure which is a fluid pressure on a first wall of the diffuser in one direction of the shaft in the vicinity of the inlet of the diffuser;

a shroud side pressure detection means for detecting a shroud side pressure which is a fluid pressure on a second wall of the diffuser in the other direction of the shaft in the vicinity of the inlet of the diffuser;

a differential pressure detection means which is connected to the hub side pressure detection means and the shroud side pressure detection means, and detects the differential pressure therebetween; and

a control means which receives a signal representing the detected differential pressure from the differential pressure detection means, and compares the detected differential pressure with a set differential pressure beforehand set so as to be lower than a surging differential pressure between the hub side pressure and the shroud side pressure at an occurrence time of surging, and outputs a signal for controlling an opening of the suction vanes in opening direction to the vane opening adjustment mechanism when the detected differential pressure becomes higher than the set differential pressure.

6. The surging prevention device for a centrifugal compressor in accordance with claim 5, wherein the control means calculates a pressure gradient with respect to time in the detected differential pressure, and calculates predicted occurrence time of surging based on the pressure gradient, the detected differential pressure and the surging differential pressure between the hub side pressure and the shroud side pressure and outputs a signal representing the predicted occurrence time of surging, and further comprising a display means which receives a signal representing the predicted occurrence time of surging from the control means, and displays the predicted occurrence time of surging.

7. In a refrigeration apparatus having a centrifugal compressor including an impeller mounted on a shaft and a housing accommodating the impeller and a diffuser formed so that an inlet of the diffuser confronts an outer periphery of the impeller, a condenser, a pressure reducing means and an evaporator sequentially connected by a refrigerant piping, and a hot gas bypass line having a hot gas bypass valve arranged so as to connect the condenser to the evaporator, the refrigeration apparatus comprising:

a hub side pressure detection means for detecting a hub side pressure which is a fluid pressure on a first wall of the diffuser in one direction of the shaft in the vicinity of the inlet of the diffuser;

a shroud side pressure detection means for detecting a shroud side pressure which is a fluid pressure on a second wall of the diffuser in the other direction of the shaft in the vicinity of the inlet of the diffuser;

a differential pressure detection means which is connected to the hub side pressure detection means and the shroud side pressure detection means, and detects the differential pressure therebetween; and

a control means which receives a signal representing the detected differential pressure from the differential pressure detection means, and compares the detected differential pressure with a set differential pressure beforehand set so as to be lower than a surging differential pressure between the hub side pressure and the shroud side pressure at an occurrence time of surging, and outputs an operation signal for opening the hot gas bypass valve when the detected differential pressure becomes higher than the set differential pressure.

8. In a surging prevention device for a centrifugal compressor including an impeller mounted on a shaft, a housing which accommodates the impeller and a diffuser formed so that an inlet of the diffuser confronts the outer periphery of the impeller, suction vanes and a vane opening adjustment mechanism for adjusting opening of the suction vanes, the surging prevention device for a centrifugal compressor comprising:

a hub side pressure detection means for detecting a hub side pressure which is a fluid pressure on a first wall of the diffuser in one direction of the shaft in the vicinity of the inlet of the diffuser;

a shroud side pressure detection means for detecting a shroud side pressure which is a fluid pressure on a second wall of the diffuser in the other direction of the shaft in the vicinity of the inlet of the diffuser;

a differential pressure detection means which is connected to the hub side pressure detection means and the shroud side pressure detection means, and detects the differential pressure therebetween; and

a control means which receives a signal representing the detected differential pressure from the differential pressure detection means, and compares the detected differential pressure with a set differential pressure beforehand set so as to be lower than a surging differential pressure between the hub side pressure and the shroud side pressure at an occurrence time of surging, and outputs a signal for stopping the centrifugal compressor when the detected differential pressure becomes higher than the set differential pressure.

9. In a surging prevention device for a centrifugal compressor including an impeller mounted on a shaft, a housing which accommodates the impeller and a diffuser formed so that an inlet of the diffuser confronts the outer periphery of the impeller, suction vanes and a vane opening adjustment mechanism for adjusting opening of the suction vanes, the surging prevention device for a centrifugal compressor comprising:

a hub side pressure detection means for detecting a hub side pressure which is a fluid pressure on a first wall of the diffuser in one direction of the shaft in the vicinity of the inlet of the diffuser;

a shroud side pressure detection means for detecting a shroud side pressure which is a fluid pressure on a second wall of the diffuser in the other direction of the shaft in the vicinity of the inlet of the diffuser;

a differential pressure detection means which is connected to the hub side pressure detection means and the shroud side pressure detection means, and detects the differential pressure therebetween; and

a control means which receives a signal representing the detected differential pressure from the differential pressure detection means, and compares the detected differential pressure with a predetermined surging differential pressure between the hub side pressure and the shroud side pressure at an occurrence time of surging, and outputs a signal for stopping the centrifugal compressor when the detected differential pressure becomes higher than the predetermined surging differential pressure.