Fluid pulsation apparatus

Claim 1

Fluid pulsation apparatus having a fluid inlet and outlet for converting a continuous stream of fluid flowing under pressure into the inlet into a pulsating stream exiting from the outlet, comprising: a generally tubular elastomeric sleeve having upstream and downstream ends which communicate, respectively, with the apparatus inlet and outlet and which is designed to expand circumferentially in response to internal pressure generated by the inlet fluid stream; a generally tubular rigid housing surrounding the elastomeric sleeve and designed to restrict its circumferential expansion to a predetermined expansion limit; fluid barrier means located within the elastomeric sleeve for blocking fluid flow through that sleeve to the outlet when the barrier means is held in an upstream closed position; and bias means positioned between the inlet and the barrier means for biasing the barrier means in its closed position in opposition to an internal fluid pressure generated within the elastomeric sleeve between its upstream end and the barrier means by the inlet fluid stream, the bias means selected to allow the barrier means to open when the internal fluid pressure reaches a first level which is sufficient to cause the elastomeric sleeve to expand circumferentially to the predetermined expansion limit, but is less than the static pressure of the inlet fluid, where the barrier means remains open until the internal fluid pressure drops to a second level less than the first level, and where the flow of fluid downstream of the barrier means is sufficiently unrestricted to permit the internal fluid pressure to drop below the second level when the barrier means is open, whereby the barrier means is caused to sequentially open and close, generating the pulsating fluid stream at the outlet of the apparatus.