Self draining valve

Details Self draining valve Self draining valve

2002-01-30

2004-02-10

Hirsch, Paul J. (Department: 3754)

Valves and valve actuation

Fluid actuated or retarded

Pilot or servo type motor

C251S129170, C251S331000

Reexamination Certificate

active

06688577

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to fluid valves, and, particularly to fluid valves that are electrically controllable and allow for automatic self draining upon removal of supply fluid pressure from the valve.
BACKGROUND OF THE INVENTION
Electronically operated valves that control fluid flow in an on/off manner are used in many applications. Electronically operated valves that use a diaphragm to control fluid flow wherein the diaphragm deflects in response to hydraulic forces formed by the flow of fluid through the valve are known in the art as a diaphragm valve. One example of such a prior art valve is depicted as reference number
10
in
FIGS. 1-3
. The valve involves a diaphragm
103
that is in contact with an opening or diaphragm seat
108
formed on an outlet tube
110
and which has a lower surface
114
. The valve
10
has a solenoid armature
105
that plugs a control opening
112
in the middle of the diaphragm
103
. The control opening is also located over the outlet tube opening
108
. When fluid supply under pressure is applied at the inlet tube
101
, the diaphragm top surface
113
(in the orientation shown in
FIG. 1
) is exposed to a fluid pressure approximately equal to the supply fluid pressure because the fluid delivered to the inlet tube
101
is in communication with the diaphragm top surface
113
through rim hole
104
. Rim hole
104
is located remotely from the outlet tube opening
108
and has a diameter smaller than control opening
112
. The entire diaphragm top surface
113
is exposed to fluid pressure that is approximately equal to the supply pressure, while only the area of the diaphragm bottom surface
114
that is not within the outlet tube opening
108
is exposed to the same pressure. Since more area of diaphragm top surface
113
is exposed to the supply pressure than diaphragm bottom surface
114
, the diaphragm
103
is forced into contact with and a seal is formed between the diaphragm
103
and the outlet tube opening
108
.
When the solenoid armature
105
is retracted into the solenoid cavity
115
through the application of current to the solenoid coil
107
, the control opening
112
allows fluid from the upper chamber
111
to drain into the outlet tube
110
because the pressure in the outlet tube
110
is less than the supply pressure in the inlet tube
101
. Since the size of the rim hole
104
is smaller than the control hole
112
, more fluid passes out of the upper chamber
111
and into the outlet tube than is admitted through the rim hole
104
. This results in a drop in pressure (and resulting force) against the diaphragm top surface
113
, thereby resulting in a lifting of the diaphragm
103
by the pressure along the diaphragm bottom
114
, thus causing the valve to open.
Once the valve is in the open state, i.e. the diaphragm
103
is away from the outlet tube opening
108
, the flow of fluid between the outlet tube opening
108
and the diaphragm bottom
114
results in a drop in fluid pressure near the outlet tube opening
108
. If the solenoid armature
105
is re-engaged into the control hole
112
, higher pressure will again develop along the diaphragm top
113
by fluid entering the rim hole
104
and combined with the lower pressure along the diaphragm bottom
114
, the diaphragm
103
will re-engage the outlet tube opening
108
, thereby closing the valve.
The prior art valve in the instant example utilizes a diaphragm
103
that is designed and located so as to be stable in one of two states. When supply fluid pressure is present and the solenoid armature
105
is engaged into the control opening
112
of the diaphragm
103
, the diaphragm
103
remains in the down, or closed, state. When supply fluid pressure is present and the solenoid armature
105
is removed/lifted from the control opening, the diaphragm
103
moves “up”, or to the open state. Upon removal of supply fluid pressure, the diaphragm
103
returns to the “down” state wherein the diaphragm
103
re-engages the outlet tube opening
108
.
FIGS. 2 and 3
also demonstrate diaphragm
103
resting atop diaphragm seat
108
in a relaxed state whether or not armature housing
403
is placed in sandwiching relation thereupon, in the absence of supply fluid pressure. That is, in the prior art valve shown in
FIGS. 1
,
2
and
3
, diaphragm
103
remains in sealing engagement with seat
108
in the absence of input fluid pressure in inlet tube
101
and with or without the influence of armature
105
.
The prior art valve illustrated in
FIG. 1
remains “closed” even when the supply fluid pressure is removed. In some applications, such as in hot tubs and whirlpool baths, the fluid may contain undesirable material such as bio-matter. Allowing the fluid with this undesirable matter to remain in the closed valve and associated tubing for an extended period of time may result in contamination of the fluid, valve and tubing and an unsanitary condition.
It is to be noted that this short coming in presently available valves applies to virtually any type of valve, not just diaphragm valves. All valves, gate valves, and all the others known to those of skill in the art, are designed so as to prevent fluid flow across the valve boundary when the valve is in its closed state. Consequently, use of any such pre-existing valve in applications such as those referenced above is less than desirable.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved valve design that automatically provides for drainage of the valve upon removal of supply pressure.
In its preferred form the invention employs a modification of the prior art valve shown in
FIGS. 1-3
such that the diaphragm, in its “at rest” position (as shown in FIG.
6
), namely, when the supply fluid pressure is equal to or approximately zero, is spaced from seat
108
a distance sufficient to readily permit the flow of supply fluid from inlet conduit
101
to outlet conduit
110
. In this way, when the flow of liquid is discontinued through the valve, any remaining liquid in the valve can freely drain, also permitting the entire system of conduits to which the valve is connected to drain as well.
The existing valve can be modified by lowering the position of the seat
108
relative to the at rest location of the bottom surface
114
of diaphragm
103
, raising the lower surface
114
of diaphragm
103
relative to seat
108
, or permitting the position of one or the other to be adjusted depending upon the viscosity and other characteristics of the supply liquid.
The present invention achieves this and further objectives by providing a valve having three stable states. When input fluid pressure is applied and the solenoid is de-energized, the diaphragm seats against seat
108
, terminating flow through the valve, as with prior art valves. When input fluid pressure is applied, and the solenoid is energized, fluid can flow between volumes
101
and
109
as in the prior art. However, when input fluid pressure is removed, the valve is constructed so as to cause the diaphragm to enter a third, stable, state wherein the diaphragm does not seat against the orifice seat
108
of the outlet tube, but is partially removed from that orifice, causing the valve to remain open so that fluid on either side of the diaphragm can drain off.


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