The present invention is directed generally to a bleed control apparatus for fluid conveying systems and more particularly to such an apparatus for eliminating the problem of surging in vacuum air systems and pressurized air systems.
Fluid conveying systems such as central vacuum systems for large commercial or industrial buildings or pressurized air systems for industry or waste water treatment plants experience a problem of surging in low flow situations. Surging is reverse flow of fluid in the system and is related to the piping system geometry. The surging problem may be solved by providing an air bleed in the system just upstream of the vacuum producer or just downstream from a compressor to allow additional air into the system, thereby to maintain air flow at a level above the surge limit and to prevent excessive heating of discharge air.
A flow actuated bleed valve was previously disclosed in Bailey U.S. Pat. No. 3,685,530. Whereas that valve was likewise designed to eliminate surging, it was somewhat cumbersome, requiring a long rotary movement of a valve paddle and experienced servicing problems relating to adjustment and access.
The alternative has been to provide a substantially more expensive electronic bleed control system which likewise requires expensive specialized service and which is cost prohibitive for many installations.
A primary object of the present invention therefor is to provide an improved bleed control apparatus for a fluid conveying system,
Another object is to provide a bleed control apparatus which is a self-contained flow actuated valve.
Another object is to provide a bleed control apparatus in which the valve member is of simple construction, minimizes interference with flow through the conduit on which it is mounted and may be quickly and easily installed in and removed from the apparatus.
Another object of the invention is to provide a bleed control apparatus which is externally adjustable for varying valve spring tension and orifice opening size.
Another object of the invention is to provide a bleed control apparatus which is simple and rugged in construction, economical to manufacture and efficient in operation.