Device for bypassing flow rate pulsations around a flow rate transducer

Abstract

A device for bypassing flow rate pulsations resulting in reverse flow and abrupt flow rate surges around a volumetric flow rate transducer includes a housing defining a chamber. One end of the chamber is coupled in fluid communication with the inlet or upstream side of the transducer while the other end of the chamber is coupled in fluid communication with the outlet or downstream side of the transducer. A flexible, fluid impervious diaphragm is mounted in the housing so as to divide the chamber into two compartments. The diaphragm is affixed to the walls of the chamber so as to maintain a fluid seal between the two compartments of the chamber. When a forward flow rate pulsation occurs the resultant rise in the fluid pressure differential between the upstream and downstream compartments of the chamber will shift the diaphragm toward the downstream compartment. As the diaphragm moves, fluid is forced out of the downstream compartment and into the fluid stream on the downstream side of the transducer. After the pulse reaches its maximum and the flow begins to reverse, the reverse flowing fluid will drive the diaphragm back toward the compartment coupled to the upstream side of the transducer. As this occurs, the volume of the fluid that was driven into this chamber during the flow rate increase is exhausted from the upstream side of the chamber and is driven into the fluid stream upstream of the transducer. The net effect of the operation of the pulsation bypass device is to allow flow rate pulsations resulting in reverse flow to pass through the diaphragm, isolating the flow transducer from the pulsations by allowing the diaphragm to flex against the biasing spring and time averaging the flow through the transducer. Thus, the transducer is not exposed to sudden increases or decreases in flow rate.