Liquid ring pump port member having anti-cavitation constructions

A liquid ring pump comprising:

• a pump housing defining a chamber that is substantially enclosed and that contains a quantity of liquid;
• a rotor at least partially disposed in the chamber the rotor including a shaft supported for rotation about a rotational axis and a plurality of blades extending radially from the shaft, the plurality of blades defining a conical interior space;
• and
• a port member disposed at least partially within the conical interior space, the port member defining an inlet port in fluid communication with a low pressure region, a discharge port in fluid communication with a high pressure region, and an anti-cavitation port in fluid communication with a fluid supply having a pressure between the low pressure region and the high pressure region, the plurality of blades arranged such that each pair of adjacent blades cooperates with the liquid and the port member to substantially enclose and define a variable volume bucket, wherein rotation of the rotor selectively positions a first bucket of the plurality of buckets in an inlet position adjacent the inlet port to draw low pressure fluid into the bucket, in an anti-cavitation position wherein the bucket is adjacent the anti-cavitation port and fluid is admitted into the first bucket, and a discharge position wherein the first bucket is positioned adjacent the discharge port to discharge fluid from the bucket to the high pressure region.

A method of reducing cavitation in a liquid ring pump comprising:

• defining a plurality of buckets between adjacent blades of a rotor;
• forming a liquid ring around the blades, the liquid ring and the blades cooperating to enclose each of the buckets such that as the buckets rotate about a rotational axis the volume within each bucket varies as a result of movement of the liquid ring with respect to the rotor;
• rotating a first of the plurality of buckets to a closed position wherein the bucket is substantially sealed and the volume of the bucket is at a minimum volume;
• rotating the first of the plurality of buckets to an intake position in which the bucket is in fluid communication with an inlet port;
• maintaining fluid communication between the first bucket and the inlet port during further rotation of the bucket during which the liquid ring moves radially away from the rotational axis with respect to the first bucket to expand the volume of the first bucket and draw fluid into the volume via the inlet port;
• rotating the first of the plurality of buckets to an anti-cavitation position wherein an anti-cavitation port is in fluid communication with the first bucket;
• admitting a flow of fluid into the first bucket via the anti-cavitation port to increase the pressure within the first bucket;
• rotating the bucket to a full discharge position in which the first bucket is in fluid communication with a discharge port and is not in fluid communication with the anti-cavitation port;
• and
• maintaining fluid communication between the first bucket and the discharge port during further rotation of the first bucket during which the liquid ring moves radially toward the rotational axis with respect to the first bucket to reduce the volume of the first bucket and discharge fluid from the volume via the discharge port.