SPECIFICATION

BACKGROUND OF THE INVENTION

This invention relates generally to in-line fluid flow check valves or back flow preventers, and more particularly concerns an improved construction which positions the closure member support downstream of the checked orifice, thereby enhancing fluid flow capa¬ bilities through reduced pressure drop.

In-line poppet type check valves currently in use of the type disclosed in U.S. Patents 2,918,083, and 2,928,416, employ poppet and/or cooperating seat constructions which during the non-check or flow condi¬ tion, result in highly turbulent flow regimes downstream of the flow checked orifice. As those skilled in the art will readily recognize these highly turbulent regimes result in greatly increased pressure drop through the check valve, sometimes requiring an increase in diameter in order to achieve an acceptable flow ^' char¬ acteristic in a given application.

The check valve of the invention disclosed here overcomes many of the pressure drop problems of current¬ ly used units, and demonstrates substantially decreased pressure drop or increased flow capability. The improve¬ ment demonstrated by the valve of this invention is achieved through positioning the poppet closure member, poppet stem support, and closure spring downstream of the checked orifice. Applicant has discovered that proper placement of the poppet and associated support elements adjacent the downstream flow areas establishes an elementary convergent/divergent flow passage result¬ ing in substantially reduced pressure drop in the unchecked or open positions.

Accordingly, it is the object of this invention to provide an in-line poppet type check valve or back flow preventer wherein pressure drop through the valve in its' unchecked or open position is substantially less than units in current use.

It is a further object of this invention to provide an in-line check valve utilizing a coaxial poppet closure member coacting with a seat seal wherein the seat seal is retained during high flow conditions by an angularly oriented seal groove.

It is a further object of this invention to provide an in-line check valve of the poppet type where¬ in the poppet stem support acts as an anti- urbulent baffle downstream of the checked orifice.

It is an additional object of this invention to integrate into the assembled valve a secondary sealing feature by metal-to-metal contact between the insert assembly and body.

BRIEF DESCRIPTION OF THE DRAWINGS

• Figure 1 is a sectional view of the check valve of the invention showing only the flow control insert assembly.

Figure 2 is a sectional view of the check valve of the invention particularly showing the flow control insert positioned within a housing of the preferred embodiment.

Figure 3 is a performance curve of the check valve of the invention in the open or unchecked posi¬ tion, wherein pressure drop through the improved valve is compared to that ^' of valves in current use.

DETAILED DESCRIPTION OF THE INVENTION

Referring first to Figure 2 with occasional reference to Figure 1, the disclosed improved check valve comprises insert assembly 3 positioned internal of a preferred housing 1. The insert assembly 3 incorpo¬ rates a flow inlet 6 in fluid communication with a flow orifice 15, having a circumferential seal 18 contained by an angularly disposed groove 22. Flow through the orifice 15 in the check position is controlled by an axially positioned poppet 19 having a poppet stem 24, and a poppet head 22. The poppet head 22 in check opera¬ tion cooperates with the seal 18, thereby shutting off flow through the orifice 15 in the check or non-flow direction.

The poppet stem 24 reciprocates within the con¬ centric poppet guide 28. The concentric guide 28 has outboard support in the form of a plurality of support vanes or flow baffles extending from the insert base to the further extension of the concentric guide. Typical¬ ly, four vanes spaced ninety radial degrees are employed. A poppet closure spring 23 is contained inter¬ mediate the poppet head 22 and the opposite end of the concentric poppet guide 28.

Surrounding the poppet insert assembly particu¬ larly adjacent to the downstream extension of the poppet stem 24 and support vane or baffle 28, are the body first flow length 12 and abutting second flow length 11. In keeping with the invention disclosed, the down¬ stream portion of the poppet concentric guide 28 is posi¬ tioned so as to have a predetermined extension into or overlap 13 with the upstream portion of the converging or second flow length 11.

In non-check or flow operation, fluid entering the inlet 6, upon exceeding the pressure required to

overcome the preset bias of poppet spring 23 due to force exerted on the upstream face of the poppet 19, lifts the poppet head 22 from its' sealing cooperation with seal 18 as positioned within angularly disposed or the oblique groove 22. Lift off of the poppet head 22 from sealing engagement with seal 18 allows fluid flow through the orifice 15, along the direction of arrows 29 and into 'a relief flow passage generally shown as 16, in the direction of arrow 30. Applicant has discovered that the presence of the flow baffles 28, poppet stem 24, and bias spring 23, inhibit the information of turbu¬ lent vortices 31 in the portions 11 and 12 of passage 16, resulting in substantially reduced pressure drop during flow conditions. Further, during non-check or flow conditions, the combination of first flow length or portion 12, and second flow length or portion 11, cooper¬ ate with the aforementioned support vanes 28 to estab¬ lish an elementary convergent/divergent nozzle.

In either flow or check operation, containment of the valve internal fluid is greatly enhanced through the use of primary and secondary seals. As shown, a primary radial seal 32 is contained in a peripheral groove 34 located on the inlet adapter 5, intermediate first and second threaded portions, i.e. 39 and 40, respectively. Contained in the groove 34 is a static seal 32. The groove 34 has at its inlet end, a shoulder 35, abutting and terminating the internal end of the threaded section 39. As shown, in its assembled posi¬ tion the inlet adapter 5 is in interference abutment with connoidal section 38 of the housing 1. The sealing combination of peripheral seal 32 and cooperating surfac¬ es 32 and 35 essentially eliminate any possibility of non-containment of valve internal fluid via leakage from pressurized fluids internal of the housing 1 upstream of

the orifice 15, when the poppet 22 is operating in its check position (reference Figure 2) .

As it is apparent that there has been provided in accordance with the invention an In-Line Check Valve Having Combined Downstream Poppet Support and Flow Control Elements, that fully supplies the objects, aims and advantages set forth above. While the improved In-Line Check Valve has been described as a separate flow control and check element, and said flow control element in combination with a preferred convergent/diver¬ gent housing, it is evident that many alternatives, modi¬ fications, and variations will be apparent to those skilled in the art as a consequence of their comprehen¬ sion of the foregoing description. Accordingly ^* , it is intended that the invention as disclosed and claimed shall embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.