Swing check valve

Details Swing check valve Swing check valve

2000-06-09

2001-11-13

Lee, Kevin (Department: 3753)

Fluid handling

Line condition change responsive valves

Direct response valves

C137S527200, C251S284000

Reexamination Certificate

active

06314993

ABSTRACT:

This invention relates to a swing check valve also known as a flap valve and particularly to improvements in the construction and mounting of the flap member movable in the check valve.
BACKGROUND OF THE INVENTION
This concept of the flap valve has been in existence in various forms of manufacture for about 500 years. Most of these types of valve are used to allow fluid or gas to move in one direction and stop back flow when pumping is stopped. The valve comprises a valve body having a duct passing through the body with a flap member mounted on the valve body so as to pivot from an open position allowing fluid to flow through the duct to a closed position resting against a seat in the duct and closing the duct to prevent back flow thorough the duct. The valve includes a sealing disc or plate within the valve body with a mounting arrangement which allows the plate to pivot between the open and closed positions. The mounting should have a form of universal joint allowing movement without hindering the sealing such that the disc is able to accommodate wear and or misalignment without failure or allowing seepage. In addition, the valve should be manufacture in a manner which is inexpensive and provides a construction which does not allow metal parts to enter the stream in the event of damage to the valve.
Therefore further improvements to provide enhanced operation and ease of manufacture are still possible.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide a valve of this type in which the sealing disc within the valve body should has a form of universal joint allowing pivotal movement without hindering sealing such that the disc is able to accommodate wear and or misalignment with out failure or allowing seepage.
According to one aspect of the invention there is provided a check valve comprising:
a valve body having a duct through the body with an annular seat surrounding the duct through which a fluid can flow;
a flap member pivotally mounted on the valve body so as to pivot about an axis transverse to the duct from an open position allowing the fluid to flow through the duct to a closed position pressing against the seat in the duct and closing the duct to prevent back flow through the duct;
the flap member being biased to the closed position such that flow of fluid through the duct in a forward direction causes the flap member to be opened from the seat against the bias to the open position;
the flap member comprising:
a flap plate including a rigid backer plate and a front resilient layer attached to the backer plate, the backer plate and the layer being shaped for engagement of the layer with the seat
a mounting bracket having a rigid mounting plate generally parallel to the backer plate and a pivot mounting portion for mounting the mounting plate for pivotal movement about the axis;
the backer plate and the mounting plate each having at least one hole therethrough;
a connecting neck portion extending through the at least one hole of each of the mounting plate and the backer plate and interconnecting the backer plate to the mounting plate, the neck portion holding the mounting plate generally parallel to and spaced from the backer plate;
a projecting stopper portion extending from the mounting plate in a direction away from the flap plate for engaging a stop member on the valve body;
the stopper portion, the connecting neck portion and the front resilient layer being integrally molded from a resilient elastomeric material so as to provide resilient flexing movement between the flap plate and the mounting bracket.
Preferably the at least one hole comprises a single hole substantially central to the flap plate.
Preferably the neck portion has a bore therethrough from a mouth at the resilient layer and extending into the stopper portion.
Preferably the neck portion has a peripheral annular recess between the mounting plate and the backer plate.
Preferably the annular recess provides a minimum diameter of the neck portion which is approximately equal to the diameter of the hole in the backer plate and in the mounting plate.
Preferably the stopper portion has a base contacting the mounting plate and a generally conical part extending therefrom to an apex spaced rearwardly from the mounting plate.
Preferably the backer plate and the resilient layer are coextensive.
Preferably the mounting plate includes a pair of arms each at a respective side of the mounting plate and extending therefrom to a pivot shaft for supporting the mounting plate for said pivotal movement of the flap member.
Preferably each arm is formed from a part of the mounting plate bent at right angles thereto.
Preferably the part includes a first portion lying along one edge of the mounting plate and standing at right angles thereof on one side thereof and a second portion beyond said one edge and extending to an opposed side thereof for engaging the shaft.
Preferably the pivot shaft extends through an opening in the body and wherein the spring is mounted on the shaft exteriorly of the body.
Preferably the body includes two recesses each on a respective side of the body into each of which extends a respective end of the shaft and wherein each recess houses a respective spring.
Preferably the body includes a collar closely surrounding the shaft such that the spring is outside the collar and is prevented from entering the duct in the event of breakage of the spring.
Preferably the spring comprises a coil spring surrounding the shaft.
It is a second object of the present invention to provide a valve of this type which prevents the metal parts of a biasing spring from entering the fluid stream in the event of breakage of the spring after wear.
According to a second aspect of the invention there is provided a check valve comprising:
a valve body having a duct through the body with an annular seat surrounding the duct through which a fluid can flow;
a flap member pivotally mounted on the valve body so as to pivot about an axis transverse to the duct from an open position allowing the fluid to flow through the duct to a closed position pressing against the seat in the duct and closing the duct to prevent back flow through the duct;
a spring biasing the flap member to the closed position such that flow of fluid through the duct in a forward direction causes the flap member to be opened from the seat against the bias of the spring to the open position;
the flap member including a mounting plate and a pair of arms each at a respective side of the mounting plate and extending therefrom to a pivot shaft for supporting the mounting plate for said pivotal movement of the flap member;
wherein the pivot shaft extends through an opening in the body and wherein the spring is mounted on the shaft exteriorly of the body.


REFERENCES:
patent: 1885894 (1932-11-01), Campbell
patent: 3817278 (1974-06-01), Elliott
patent: 4043358 (1977-08-01), Sliski
patent: 4706706 (1987-11-01), Page et al.
patent: 5746246 (1998-05-01), Yokota et al.
patent: 6050294 (2000-04-01), Makowan
patent: 6152173 (2000-11-01), Makowan

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