Sensitive fluid balancing relief valve

#The present invention relates to a new and improved modulated pressure relief valve which balances vessel or line pressure against a reference pressure signal.

#There has been a long felt desire for a modulated pressure relief valve on a vessel for venting fluid when the pressure exceeds a desired dynamic set-point or threshold. A particular desire is for a modulated pressure relief valve with a threshold that could vary according to process requirements and its upper limit could serve to avoid blowing a safety relief device such as an expendable rupture disc or pop-off safety relief valve both of which are typically designed for infrequent use. It is desirable to communicate the desired pressure set-point to the relief valve via a reference pressure signal (typically air) that is equal to the desired vessel pressure.

#Furthermore, it is desirable to have a modulating pressure relief valve which is very simple, with cleanable parts and with no narrow passageways that can become plugged with debris or frozen product. Such a device would be useful in many applications including the food, beverage, gelatin, and polymer industries, where the product can become frozen in critical passages, and where all crevices must be exposed to the rinsing and cleaning processes.

#FIG. 1 is an exploded perspective view of an embodiment of the present invention.

#FIG. 2 is a cross-sectional view of an embodiment of the present invention.

#FIG. 3 is a schematic representation of a system incorporating the present invention.

#The invention is described with reference to the drawings. The drawings are provided to facilitate discussion of the invention and are not intended to limit the invention in any way. In the drawings all similar elements are numbered accordingly.

#An embodiment of the present invention is provided in FIG. 1. In FIG. 1, the modulated pressure relief valve, generally represented at 1, is shown in exploded perspective view. The modulated pressure relief valve, 1, comprises a diaphragm, 2, which is enclosed between an reference housing, 3, and a process housing, 4. The diaphragm, 2, comprises a reference surface, 20, and a process surface, 21, which is opposite the reference surface. For the purposes of the present application the volume between the reference surface of the diaphragm and reference housing is referred to as the reference volume and the area between the process surface of the diaphragm and the process housing is referred to as the process volume. An optional seal, 5, can be employed between the diaphragm and reference housing, between the diaphragm and process housing, or both to insure that the entire assembly is sealed relative to operating pressure ranges which are anticipated.

#The reference housing, 3, comprising a reference coupling, 9, which engages with a reference pressure source, 30. The reference coupling, 9, can be any coupling typically employed for connecting a fluid source to a device. Threaded couplings, compression couplings, ferreted couplings, soldered couplings, welded couplings, barbed couplings attached to flexible tubing and the like are imminently suitable for the demonstration of the invention. It would be well within the ability of one skilled in the art to attach a pressure system to a coupling and further description herein is not warranted.