System and method for condition monitoring of vertically suspended pumps

Abstract

A vertically suspended pump assembly configured to pump fluid from an open sump or a closed suction double casing, the vertically suspended pump assembly comprising: a motor disposed in a top portion; and one or more impellers disposed in a bottom portion and driven by the motor so that centrifugal forces are generated within a central passage way to pump fluid from the open sump or the closed suction double casing upwards through the central passage way; and a vibration sensor located at a bottom of the bowl casing or at an inlet casing of a first stage impeller; and a controller configured to receive, from the vibration sensor, a stream of data encoding one or more vibrational characteristics at the bottom of the bowl casing or at the inlet casing of the first stage impeller so that the vertically suspended pump assembly is monitored in real-time.

What is claimed is: 
     
         1 . A system comprising:
 a vertically suspended pump assembly configured to pump fluid from an open sump or a closed suction double casing, the vertically suspended pump assembly comprising:
 a top portion located above-grade at a first end of the vertically suspended pump assembly; 
 a bottom portion located below-grade at a second end of the vertically suspended pump assembly; 
 a motor disposed in the top portion; 
 one or more impellers disposed in the bottom portion and arranged in a stack within a bowl casing, wherein the one or more impellers are driven by the motor so that centrifugal forces are generated within a central passage way between the top portion and the bottom portion of the vertically suspended pump assembly to pump fluid from the open sump or the closed suction double casing upwards through the central passage way, wherein the one or more impellers comprise a first stage impeller at a bottom level of the stack; and 
   a vibration sensor located at a bottom of the bowl casing or at an inlet casing of the first stage impeller; and   a controller in communication with the vibration sensor and configured to receive, from the vibration sensor, a stream of data encoding one or more vibrational characteristics at the bottom of the bowl casing or at the inlet casing of the first stage impeller so that the vertically suspended pump assembly is monitored in real-time.   
     
     
         2 . The system of  claim 1 , further comprising:
 a vibration cable that connects the vibration sensor to the controller.   
     
     
         3 . The system of  claim 2 , further comprising:
 a pressurized pipe enclosing the vibration sensor and the vibration cable so that the vibration sensor and the vibration cable are insulated from the fluid.   
     
     
         4 . The system of  claim 3 , further comprising:
 a pressure gauge attached to the pressurized pipe and configured to measure a pressure inside the pressurized pipe.   
     
     
         5 . The system of  claim 4 , wherein the pressure inside the pressurized pipe is higher than a pressure of the fluid outside the pressurized pipe. 
     
     
         6 . The system of  claim 3 , further comprising:
 a flanged connection comprising two flanges facing each other and connected through a gasket, wherein the flanged connection is located on the pressurized pipe and by the vibration sensor such that, when the flanged connection is opened, the vibration sensor can be inspected.   
     
     
         7 . The system of  claim 2 , further comprising:
 a pressurized hose enclosing the vibration sensor and the vibration cable so that the vibration sensor and the vibration cord are insulated from the fluid.   
     
     
         8 . The system of  claim 7 , further comprising:
 a pressure gauge attached to the pressurized hose and configured to measure a pressure inside the pressurized hose.   
     
     
         9 . The system of  claim 8 , wherein the pressure inside the pressurized hose is higher than a pressure of the fluid outside the pressurized hose. 
     
     
         10 . The system of  claim 7 , further comprising:
 a flanged connection comprising two flanges facing each other and connected through a gasket, wherein the flanged connection is located on the pressurized hose and by the vibration sensor such that, when the flanged connection is opened, the vibration sensor can be inspected.   
     
     
         11 . The system of  claim 1 , wherein the one or more impellers are multi-stage impellers arranged in the stack. 
     
     
         12 . The system of  claim 1 , wherein the vertically suspended pump assembly comprises: a vertically suspended open suction pump, and a vertically suspended closed suction pump. 
     
     
         13 . A method for monitoring a vertically suspended pump assembly comprising one or more impellers arranged in a stack within a bowl casing, the method comprising:
 placing a vibration sensor at a bottom of the bowl casing or at an inlet casing of a first stage impeller of the one or more impellers;   driving the one or more impellers using a motor so that centrifugal forces are generated within a central passage way of the vertically suspended pump assembly to pump fluid from the open sump or the closed suction double casing upwards through the central passage way;   receiving, from the vibration sensor and on a controller in communication with the vibration sensor, a stream of data encoding one or more vibrational characteristics at the bottom of the bowl casing or at the inlet casing of the first stage impeller; and   monitoring the vertically suspended pump assembly in real-time as fluid is from the open sump or the closed suction double casing upwards through the central passage way.   
     
     
         14 . The method of  claim 13 , further comprising:
 connecting, using a vibration cord, the vibration sensor to the controller.   
     
     
         15 . The method of  claim 14 , further comprising:
 enclosing, using a pipe or a hose, the vibration sensor and the vibration cable so that the vibration sensor and the vibration cable are insulated from the process fluid.   
     
     
         16 . The method of  claim 15 , further comprising:
 pressurizing the pipe or hose so that a pressure inside is higher than a pressure of the process fluid.   
     
     
         17 . The method of  claim 16 , further comprising:
 measuring, using a pressure gauge, the pressure inside the pipe or the hose.   
     
     
         18 . The method of  claim 13 , further comprising:
 determining, based on, at least in part, the one or more vibrational characteristics, a condition of the vertically suspended pump assembly.   
     
     
         19 . The method of  claim 18 , further comprising:
 in response to determining that the condition of the vertically suspended pump assembly is abnormal, causing the vertically suspended pump assembly to stop operation.   
     
     
         20 . The method of  claim 13 , further comprising:
 opening a flanged connection by the vibration sensor; and   inspecting the vibration sensor.