Helium compressor with dual after-coolers

Abstract

This invention relates generally to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) cycle. This invention provides redundancy between water cooling and air cooling if there is a blockage in the water or air supply by having air and water cooled after-coolers in series or parallel.

What is claimed is: 
     
       1. A method of operating an oil-lubricated helium compressor system located in an indoor environment, the compressor system comprising;
 a compressor; 
 a separator internal or external to the compressor that receives a mixture of compressed helium and oil and discharges helium and oil through separate ports, 
 a water cooled after-cooler for effecting cooling of the helium and oil; 
 an air cooled after-cooler for effecting cooling of the helium and oil, and the air cooled after-cooler comprising a heat exchanger and a fan, the water cooled after-cooler and the air cooled after-cooler connected in series; 
 one or more sensors connected to a controller programed to detect a fault in the water cooled after-cooler, 
 a first line extending from the helium discharge port and passing through the water cooled after-cooler and the air cooled after-cooler, the helium being cooled by one or both the water cooled after-cooler and the air cooled after-cooler; and 
 a second line extending from the oil discharge port and passing through the water cooled after-cooler and the air cooled after-cooler, the oil being cooled by one or both the water cooled after-cooler and the air cooled after-cooler; 
 wherein the first line and the second line are separate; 
 
       the method comprising the steps of:
 (a) running the compressor with water flowing through the water cooled after-cooler, 
 (b) detecting a fault in the water cooled after-cooler, 
 (c) turning on the fan. 
 
     
     
       2. The method in accordance with  claim 1 , further comprising the step of having the fan on all the time. 
     
     
       3. A method of operating an oil-lubricated helium compressor system located in an indoor environment, the compressor system comprising;
 a compressor; 
 a separator internal or external to the compressor that receives a mixture of compressed helium and oil and discharges helium and oil through separate ports, 
 a water cooled after-cooler, 
 an air cooled alter-cooler; 
 one or more sensors connected to a controller programed to detect a fault in the water cooled after-cooler, 
 a first line extending from the helium discharge port and passing through a three-way valve then one of the water cooled after-cooler and the air cooled after-cooler, the helium being cooled by the respective water cooled after-cooler or the air cooled after-cooler; and 
 a second line extending from the oil discharge port and passing through a three-way valve then one of the water cooled after-cooler and the air cooled after-cooler, the oil being cooled by the respective water cooled after-cooler or the air cooled alter-cooler;
 wherein the first line and the second line are separate.,  
 
 
       the method comprising the steps of:
 (a) running the compressor with the helium and oil being cooled by the water cooled after-cooler, 
 (b) detecting a fault in the water cooled after-cooler, 
 (c) switching the flow of helium and oil from the water cooled after-cooler to the air cooled after-cooler. 
 
     
     
       4. An oil lubricated helium compressor system which is located in an indoor environment where the ambient air temperature is between 15° C. and 30° C., the compressor system comprising:
 a compressor; 
 a separator internal or external to the compressor that receives a mixture of compressed helium and oil and discharges helium and oil through separate ports; 
 a water cooled after-cooler for effecting cooling of the helium and oil; 
 an air cooled after-cooler for effecting cooling of the helium and oil, the air cooled after-cooler comprising a heat exchanger and a fan, the water cooled after-cooler and the air cooled after-cooler connected in series; 
 a first line extending from the helium discharge port and passing through the water cooled after-cooler and the air cooled after-cooler, the helium being cooled by one or both the water cooled after-cooler and the air cooled after-cooler; 
 a second line extending from the oil discharge port and passing through the water cooled after-cooler and the air cooled after-cooler, the oil being cooled by one or both the water cooled after-cooler and the air cooled after-cooler, wherein the first line and the second line are separate; 
 a temperature sensor mounted downstream of the water cooled after-cooler, wherein the temperature sensor senses temperature of the helium or oil leaving the water cooled after-cooler; and 
 a controller configured to turn on the fan when the temperature exceeds a defined temperature.  
 
     
     
       5. The compressor system in accordance with claim 4, wherein the first line and the second line pass through the water cooled after-cooler before the air cooled after-cooler.  
     
     
       6. An oil-lubricated helium compressor system located in an indoor environment where the ambient air temperature is between 15° C. and 30° C., the compressor system comprising:
 a compressor; 
 a separator internal or external to the compressor that receives a mixture of compressed helium and oil and discharges helium and oil through separate ports; 
 a water cooled after-cooler; 
 an air cooled after-cooler connected in parallel to the water cooled after-cooler; 
 a first line extending from the helium discharge port and passing through a three-way valve then one of the water cooled after-cooler and the air cooled after-cooler, the helium being cooled by the respective water cooled after-cooler or the air cooled after-cooler; 
 a second line extending from the oil discharge port and passing through a three-way valve then one of the water cooled after-cooler and the air cooled after-cooler, the oil being cooled by the respective water cooled after-cooler or the air cooled after-cooler, wherein the first line and the second line are separate; 
 a temperature sensor mounted downstream of the water cooled after-cooler, wherein the temperature sensor senses temperature of helium or oil leaving the water cooled after-cooler; and 
 a controller configured to turn on the fan and to switch the three-way valves so the helium and oil flow through the air cooled after-cooler, when the temperature exceeds a defined temperature.  
 
     
     
       7. The oil-lubricated helium compressor system in accordance with claim 6, wherein the oil and helium flow through one of the air cooled and water cooled after-coolers.