Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
FIELD OF TEE INVENTIO~
This invention relates to adjustable check valve
for use in fluid supply systems. Whilst particularly useful
for mixing water from hot and cold water supply systems, the
valve of the invention is by no means confined to that appli-
cation and may be used to control the flow of both liquids
and gasses.
BACKGROUl~D OF THE I~ TIO~
In united States Patent No. 2,830,612 there is
described an anticondensation device for a flush tank in
which hot water is injected into a cold water supply to the
tank through a check valve and a restrictor orifice. I have
experimented with this device and have found that whilst
preventing condensation it leaves several problems unsolved.
The form of checX valve employed is very prone to chatter, re-
sulting in a noise problem, and there is nothing to prevent hot
water from entering the cold water supply in the event of a
pressure drop in the latter. Furthermore, the device is not
adjustable.
-}- ,,~;
,~;
.
, .
, - . ~ , . . . .
.: ,
.
:.
'
. ' ' ' '
.'~ ' ' ' ' ' ' ' ' .
8399
I am aware of the check valve structure disclosed
in Patent No. 2,044,629 to Parker in which two valve members
are arranged in series, one of the valve members being movable
relative to the other within a chamber forming part o the
fluid path from inlet to outlet of the valve structure so as
to provide a dashpot effect on opening or closing of the valve.
I am also aware of Patent No. 2,682,890 to May for a safety
valve in where a piston operated by the pressure of fluid up- ~ -
stream of the valve acts as a lifter for the valve, and Patent
~0 ~o. 2,646,066 to Nemetz for a check valve for lubricatio~
system~ in which a first valve member in the form of a piston ~ -
acts as a lifter for a second ball-type valve. However, none
of these valve~ operates or is constructed in the same manner
as that now to be described, nor do they have the same purpose,
which is here to provide a simple yet smoothly and silently
operating adjustable check valve.
SHORT DESCRIPTIO~ OF THE ~NVENTIO~
According to the present invention, a check valve
comprises a valve housing having an inlet and an outlet, a
valve seating in the housing defining a passage between inlet
and outlet chambers defined in said housing, a ball valve
seatable on the seating on the outlet side thereof, a compres-
sion spring urging the ball onto the seat, a spring abutment
adjustably mounted in the housing, the spring acting between
the ball and the abutment to apply an adjustable bias to said
ball tending to retain it on said valve seat, a first piston
having a path of movement in the passage defined by the valve
seating, passageway means defined by the piston and extending
rom an inlet in the one end of the piston nearest the inlet
..
. , . . .': . ' : ' ~., , `
8~399
to at least one outlet in the side of the piston so positioned
that at one end of the path of movement of the piston the
outlet is within the passage in the valve seating and at the
other end of the travel of the piston is on the outlet side
of the valve seat, the other end of the piston being engage-
able with the ball valve member, and dashpot means comprising
a second piston, constrained to move conjointly with said ball
and said firs~ piston, and cylinder means receiving said sec-
ond piston for movement relative to said housing, a leakage
path being defined communicating said cylinder to control the
rate of displacement of said piston in said cylinder. With
this arrangement, although the primary closure of the valve -
is by the ball valve member, the principal fluid flow through
the valve is through the passageway in the stem and the side
outlet or outlets in the latter. The rate of flow through the
valve i8 thus regulated by the piston, whose movements are
damped to an extent determined by the magnitude of th~ leakage
path past the dashpot piston, thus enabling any necessary
degree of damping required to prevent chatter and erratic
operation to be applied without restricting flow through the
valve. The pressure drop occurring across the valve may be ~-
adjusted by moving the ad3ustable abutment, which may be the
valve stem of a conventional faucet structure.
The valves may be used in pairs, for example in hot
and cold water supplies to a flush tank or a sink, in which
case they will act both accurately to proportion the hot and
cold water supplied to the tank or sink and to prevent any
communication between the hot and cold water systems.
SHORT DESCRIPTION OF THE DRAWI~GS
A preferred embodiment of the invention is æhown in
--3--
1~81B399
the accompanying drawing, in which:
Figure 1 shows a first embodiment of check valve
in section, and
Figure 2 is a diagram illustrating a use of the
valves in accordance with the invention,
Fi~ure 3 shows a modified form of check valve in - -
section, and
Figure 4 shows a ~alve according to the invention
incorporated in a mixer tap for a sink.
DESCRIPTIO~ OF THE PREFERRED EMBODIMENTS
The valve shown in Figure 1 comprises a body 2,
which may be formed of metal, or of a high strength moulded
plastics material such as a glass loaded acetal resin such as
is available under the ~rade mark DELRIN from DuPont. The
body is formed with a bore rom one end forming an inlet
chamber 4 and a bore from the other end forming an outlet ;~
chamber 6, both bores having threaded portions 8, 10 respec-
tively at their outer ends. The bores are connected by a
further bore 12 forming a passage between the chambers 4 and
6 through a valve seat 14. A tapped side outlet 16 in the
., - .
housing into the chamber 6 receives an outlet pipe ~not shown)
from the valve, whilst an inlet pipe (not shown) engages the
threaded portion 8. An additional side orifice 17 may be
provided for purposes to be discussed below. The threaded
portion 8 also receives a retainer ring 18 which renders a - -
piston assembly captive within a cylinder ormed by the cham- -
ber 4, a second piston 20 supporting a first piston 22 which
extend~ into and substantially closes the passage 12. The
outer end of the piston 22 is recessed tD engage a ball valve
'~ , '.
835~9
member 24 normally held in fluid tight engagement with the
valve seat 14 by a spring 26 acting between a cup 28 resting
on the ball and an abutment in the form of a cup 30 on the
end of a stem 32.
The stem 32 has a screw threa~ed portion 42 engaging
an internal thread 40 on a plug 34 which has an external thread
engaging the thread 10. ~ gla~d nut 36 retains liquid tight
packing around the stem 32, which has an operating knob 38 at
its outer end. By means of the knob 38, the position of the
cup 30 may be adjusted, thus altering the pressure applied to
the ball 24 tending to keep it seated. A locking device as
shown at 37, or of any other suitable alternative design may
be used to retain a desired setting. The piston assembly has
a passageway 48 extending from the side of the assembly near-
est the inlet end of the valve through the first piston 22 to
an outlet 44 in the side of the piston 22. Preferably there
are two diametrically opposite outlets, which are normally ~ --
masked by the seat 14. Small drillings 46 in the second
piston 20 provide a leakage path between its opposite sides:
they may be replaced by notches in the edge of the second pis-
ton 20 or by slightly reducing the diameter of the second pis-
ton so as to provide the desired leakage path. Interchange-
able piston assemblies with calibrated drillings may be selec-
ted so as to provide desired forward flow characteristics. A
spring 50 surrounds the stem 22 and is dimensioned so as to
arrest the piston assembly at the end of its upward stroke.
Otber alternative means of cushioning the upward end of the
piston stroke could be employed.
When a pressure differential is applied across the
valve from inlet to outlet, sufficient for the differential
1(~813399
, :
fluid pressure applied directly or indirectly to the ball 24
to overcome the pressure applied thereto by the spring 26,
the ball will rise until the spring is compressed so that the '~
pressures applied to the ball are again balanced. I this
results in the par~s of the outlets 44 rising ab~ve the seat :~ :
14, fluid will pass from the inlet chamber to the outlet cham-
ber through the passageway 48 at a rate determined both by
how far the piston 22 can rise against the increasing pressure ~;
of the spring 26 and by how much the pre~sure drop acro3s the
valve falls: unless the spring pressure is low and the back '~
pre~sure at the outlet 16 is low, the first piston asoumes . ~-
some intermediate position with the outlets 44 partly uncover-
ed. Sudden movements or oscillations of the piston 22 are
heavily damped by the dashpot formed by piston 20 and cylinder
4 since any such movements or oscillations reguire the dis- ::
placement or induction of fluid from or into the portion of
the cylinder.~~rmed.by chamber 4 above the second piston 20 ~ .:
through the'leakage path means 46 and any other leakage paths
around the second piston 20 and the first piston 22.. Since
the flow through the valve is controlled by the interaction
of the openingæ 44 and the seat 14,there is no sudden cut-off
or commencement of flow as the ball 24 seats or unseats, and
thus a further source of noisy operation is avoided, w,hilst
additional damping at the fully open position of the valve .
is provided by the spring 50.
Referring to Figure 2, the valve of the invention
will frequently be used as one of a pair of valves 52, 54 up-
stream of some further valve 56, in order to feed controlled
preset amounts of hot and cold water from separate hot and
cold supplies 58, 60 to an outlet controlled by the single
-6- .
1~15 8399
valve 56~ one example already mentioned is the float con-
trolled valve of a flush toilet, whilst other examples are
spray nozzles for watering indoor plants where it is desired
to avoid the shock of applying very cold water during winter,
and shower heads where it is desired to avoid having to set
up a predetermined water mix to provide a desired temperature
each time the shower is used. In all of these cases, single
valve control of the mixed water involves the danger of
water from one of the hot and cold systems entering the other
unles~ check valves are provided. The adjustable check valve
of the invention enable both the check valve and tempera~ure
control ~unctions to be carried out simultaneously in valves
which are simple to construct yet stable and quiet in opera- ~
tion. The valves 52 and 54 may have a common housing 62. - -
The orifice 17 may be used to accommodate a connec-
tion to a device 18, which may be a pressure gauge, a pressure
switch, or means for introducing additives into fluids leaving
the valve. Normally speaking, the valve of the invention will
be used in series with and upstream of some further valve,
such as the float valve of a flush tank or the control valve
of a watering or dispensing valve. The pressure in the out-
let chamber 6 will alter according to whether this downstream
valve is open or closed, and the pressure gauge or ~witch
will respond to such changes to provide indication or control
function, If a dispensing device for additives i5 used, this
may also be pressure controlled so as only to release addi-
tives when the pressure in the chamber 6 falls, thus indica-
ting that the downstream valve is open. Such a dispensing
device could be another valve in accordance with the invention.
883~9
Whilst in the embodiment described above, the valve
body is of moulded plastics and the remaining parts are prefer-
ably of stainless steel, the simple construction of the valve
means that it can readily be constructed from alternative mat-
erials having appropriate anticorrosive or heat resisting
properties if corrosive or very hot fluids are to be handled.
Subject to suitable calibration of the leakage path past the
second piston, the valve works equally as well with ga~e~ as
with liquids, and will work in any attitude.
Referring now to Figure 3, a modified version of the
valve of Figure 1 is shown, in which the same reference numer-
als indicate similar parts where applicable. As compared with
the embodiment of Figure 1 the piston 20 is omitted, together
with the associated cylinder portion of chamber 4 and the sprin~ -
50. The abutment 18 is formed integrally with the body and acts
directly of the piston 20. The spring 26 is located by a sec-
ond piston 100 which extends from a spring abutment forme* by
the cup 28 into a cylinder 102 formed within the threaded por-
tion 42 of the stem 32. The fit between the second piston 100
and the cylinder 102 is such that a leakage path exists between
the cylinder and the remainder of the housing such as to permit
damped movement of the piston in and out of the cylinder, thus
providing a dashpot assembly. The second piston acts through- .
the cup 28 on the ball 24 and thence on the first pi~ton 20 so
as to damp the movements of these latter parts in the same
manner as the piston 20 in the previous embodiment. However,
manufacture of the valve is simplified since the abutment 18
is now integral with the body, and all of the parts may be
assembled into or removed from the housing from one end and
--8--
.
.. . . . . . . . ..
1.C~88399
:
without the necessity for disconnecting the valve from any
associated pipework connected at threaded apertures 16, 17 and
4.
Figure 4 shows a further modification of the valve
incorporated into the body of conventional tap or faucet, the
whole of the original structure of the latter being retained
except for the seating, the washer and the washer carrier. The
same reference numerals are utilized in Figure 4 as in Figures
l,a~d 3, wherever applicable. The stem 32 and threaded portion
42 a~ well as the plug 34, the gland 36, the knob 38, the body
2 and the outlet 16 are formed by parts of a conventional fau-
cet structure, which itself may form part of a convent~al mixer
tap together with a further faucet structure (not shown), con-
nection piece~ 104 and a swivel outlet 106. The seat 14, the
abutment 18 and the bore 12 are defined in a screw-in insert
108 which replaces a conventionalscrew-in seat, and the conven-
tional washer and carrier is replaced by the piston 22, the
ball 24, the spring 26, the cup 28, and the piston 100, the
cylinder 102 for the piston being formed by the existing bore
for receiving the stem of the washer carrier. operation is the
same as in the previous embodiment. As compared to a conven-
tional faucet structure, the troublesome washer is eliminated,
a check valve action is provided which positively prevents any
mixing of water rom the hot and cold supplies, and the dashpot
action provided by the piston and cylinder 100 and 102 prevents
` hammer or chatter. Since the ball 24 is free to rotate, and
;~ will constantly reform the seat 14 when pressed down onto the
latter as the stem 32 is screwed down to close the valve,
~ leakage problems should be substantially eliminated. Moreover,
.~ _g_ .
.
, :
1~8~3399
a wide range o existing faucet structures can readily be
converted to the structure of the invention merely by replace-
ment of those parts which are usually in any event subject to
replacement during the life of a faucet.
--10--
