Fluid handling – Self-proportioning or correlating systems – Supply and exhaust type
Reexamination Certificate
2001-09-28
2004-07-06
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Self-proportioning or correlating systems
Supply and exhaust type
C137S115140, C137S115150, C137S116300
Reexamination Certificate
active
06758234
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to improvements in and relating to valves and valve systems for use in controlling the flow of fluids.
BACKGROUND OF THE INVENTION
In particular the present invention relates to improvements relating to valves and valve systems wherein a valve is used to control the flow of fluid between high pressure and low pressure fluid systems.
In general, the fluid may be a liquid. However, this should not be seen as limiting as the present invention may also be utilized to regulate the flow of other fluids such as gases for example.
Valves which regulate the flow of fluid between high pressure and low pressure fluid systems are known. However, they all suffer from a number of disadvantages.
One type of valve used to regulate the pressure between a high pressure and low pressure fluid system is the pressure reducing or pressure equalizing valve, such as the AJAX® valve. This type of valve is commonly used to regulate the flow of high pressure (“HP”) mains water (generally in the order of 20-100 PSI) as it enters a low pressure (“LP”) hot water storage cylinder (generally having a maximum internal pressure threshold of approximately 10 PSI).
In
FIG. 1
there is shown a typical prior art standard pressure reducing valve generally indicated by arrow
1
. The valve has a valve body
2
, an HP inlet
3
connected to a mains water supply and a LP outlet
4
connected to a low pressure hot water storage cylinder. The valve also has a rubber diaphragm
5
which is attached via a bracket
6
to a rubber washer
7
. Diaphragm
5
is also attached to a spring
8
which is capable of having its tension adjusted.
The rubber diaphragm
5
is sensitive to pressure changes within the hot water cylinder (“LP fluid system”) and either moves in the direction of arrow A when there is an increase in pressure in the LP fluid system, or moves in the direction of arrow B when there is a decrease in pressure in the LP fluid system.
The sensitivity of the rubber diaphragm
5
to pressure changes within the LP fluid system can be adjusted by altering the tension of spring
8
.
When valve
1
is in use, as pressure builds in the LP fluid system this causes washer
7
to also move in direction A and to contact a valve seat
9
to shut off the water supply from inlet
3
. Conversely, if the pressure within the LP fluid system is reduced the diaphragm and washer move in the direction of arrow B which allows water to enter the LP fluid system.
However, this type of valve suffers from a number of drawbacks.
One drawback with such valves, is that the seal between washer
7
and valve seat
9
is prone to being compromised due to small particles either damaging or obstructing the sealing face. Thus, this drawback can lead to a constant flow of water into the LP fluid system.
A further disadvantage with such valves is that poor construction of the valve can lead to washer
7
not being in proper alignment with seat
9
, thereby allowing HP water effectively to bypass the valve and enter the LP fluid system in an uncontrolled manner.
A further drawback with this type of valve is that if the sensitivity of rubber diaphragm
5
is not adjusted properly HP water can again effectively bypass the valve and enter the LP system.
A further disadvantage with such valves is that if there is an increase in pressure in the mains water supply, this increase may be sufficient to overcome the force being applied to the washer via the diaphragm so that HP water can enter the LP fluid system in an uncontrolled manner.
In addition to the above drawbacks, the use of standard pressure reducing or equalizing valves, such as described in relation to
FIG. 1
, in commercial or household hot water systems can also create a number of other problems.
The aforementioned type of valve due to its construction requires a hot water cylinder be fitted with a vent pipe. The presence of a vent pipe creates a number of problems which include:
The expense involved in creating a hole through the roof and flashing for the vent pipe;
One pipe circulation in the vent pipe caused by thermo-syphoning resulting in continual power wastage as the hot water that cools in the vent pipe needs to be reheated in the hot water cylinder; and
Burst hot water cylinders caused by frozen vent pipes leading to flooded premises and expensive repairs, as well as to increase the risk of electrocution.
A further disadvantage that occurs with this type of valve is that the diameter of the inlet orifice of the high pressure system must be reduced to allow the pressure of the LP fluid system, as amplified by the diaphragm, to equalize the pressure of the fluid at the HP inlet. As a result, the water pressure from this type of hot water system has a poor flow pressure at most outlets.
Another type of pressure reducing valve which suffers from the same drawbacks as described above is disclosed in NZ 153402/154210. The valve disclosed in this specification uses a flexible sleeve sensitive to pressure changes in a LP fluid system, to cause a valve head to move into or out of contact with a valve seat, located at the end of a high pressure fluid inlet.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a valve assembly which includes:
At least one valve port;
At least one fluid inlet; and
An outlet for connection to a fluid system;
characterized in that the valve assembly includes a pressure sensitive member which is connected to the outlet, so that the size of the pressure sensitive member is capable of increasing or decreasing in response to pressure changes within the fluid system, wherein the valve is configured so that said increases or decreases to the size of the pressure sensitive member cause the inlet and valve port to move either into or out of alignment with one another.
According to another aspect of the present invention there is provided a valve assembly substantially as described above wherein the valve assembly includes a relief outlet.
According to another aspect of the present invention there is provided a valve assembly substantially as described above wherein the valve assembly includes a relief outlet, characterized in that the valve assembly is configured so that the pressure sensitive member will increase in size to an extent that enables the member to move the relief outlet and valve port into alignment with one another, if a predetermined pressure threshold limit is reached.
According to a further aspect of the present invention there is provided a valve assembly wherein the valve assembly (“Mod Assembly”) includes:
a) At least one valve port;
b) A first opening;
c) Second opening or openings;
d) Third opening or openings; and
e) A pressure sensitive member;
characterized in that the valve assembly is configured so that the position of the pressure sensitive member is capable of being altered solely in response to pressure changes within a fluid system to which the first opening is connected, wherein said changes in the position of the pressure sensitive member cause the valve port to move either into or out of alignment with the second or third opening, so that the valve port is moveable to each of the following positions:
a) At least partially aligned with the second opening or openings but not the third opening or openings; or
b) At least partially aligned with the third opening or openings but not the second opening or openings; or
c) Non-aligned with either the second or third openings.
According to another aspect of the present invention there is provided a method of operating a valve assembly connected to a high pressure inlet of a relatively low pressure fluid system so as to regulate inlet flow into the system, the method characterized by the step of:
a) Utilizing a pressure sensitive member to move
Hepperle Stephen M.
Lowe Hauptman Gillman & Berner LLP
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