[0001] The invention relates to a reducing valve adapted to be controlled by means of a
stay or stays on the basis of a superatmospheric pressure.
[0002] Such valves find particularly use in respirators in which they serve for reducing
inlet pressure from a pressurized vessel to the pulmonary pressure with a superatmospheric
pressure relative to the ambient atmosphere.
[0003] Respirators are usually provided either with a one-stage automatic pulmonary system
wherein pressure prevailing in a pressurized vessel (of, say, 20 MPa) is reduced to
the pulmonary pressure by a single closing element, or with a two-stage system in
which the first stage is associated with the pressurized vessel while the second as
a rule with the mask. In the last years, however, such systems have not experienced
any substantial progress, since any simplification of leverage mechanisms they are
based upon are rather limited.
[0004] Among other systems there may be named a device according to the Czechoslovak Inventorship
Certificate No. 250,347, comprising a single bent controlling stay which is received
in the mask and air-tightly closed by a diaphragm as well as a device described in
the Czech. Inv. Cert. No. 269,068 comprising a pair of bent stays provided in an air-tight
bag. The two above-mentioned systems do not operate but in subatmospheric pressure
respirators which, however, cannot be used for superatmospheric pressure breathing
regimes. With subatmospheric apparatuses, namely, any leakage may cause contaminants
to be aspirated from the ambient atmosphere so that the workers operating in media
of concentrated toxicity may become endangered. On the contrary, the superatmospheric
pressure respirators guarantee the operator's safety in such media even in case of
any leakage within the breathing cycle, and particularly due to a constant superatmospheric
pressure under the mask produced by lungs in any breathing regime, so that any of
unwanted substances are rather ejected than aspirated.
[0005] It is the object of the present invention to provide a valve controlling stay system
which operates solely under Superatmospheric pressure and the stays form directly
a bag. The invention is based upon the disclosure of the above-mentioned Czech. Inv.
Cert. No. 269,068 modified by the reversion of the function and by removing the bag.
According to the two above-cited references, the bent stays have in the inoperative
position the shortest length, the valve they control is closed, and the regulation
occurs by producing a vacuum in the bag, such vacuum straightening the bent stays,
i.e. prolonging them, and consequently opening the valve. On the contrary, in accordance
with the present invention, the straight stays, in inoperative position when no pressure
is let in from the pressurized vessel, have the longest form and keep the valve open.
The latter is closed until pressure is let in from said vessel, and the medium is
allowed to flow through the opened valve into the space of reduced pulmonary pressure
till an overpressure in this space has arisen. Such overpressure causes the stays
to diverge or bend away whereby they become shorter, the valve takes up its seat,
and the medium flow is cut off. Owing to the overpressure re-drop, the stays begin
to assume their straight form, viz. to extend their length, and open thus the valve
of throttle device. This cycle is then repeated ad infinitum. On their periphery,
the stays are gas-tightly closed by means of an elastic fold joint so that they are
allowed to diverge from each other and form thus therebetween a variable space or
bag. The space communicates gas-tightly with a rubber forechamber which confines the
entire automatic system and enables the medium to be let in and out. The device according
to the invention makes it possible to control the valve, after having been exposed
to pressure, with the exception that the stay is attached to the valve body at the
opposite side, relative to the connection with a holder which latter constitutes then
a valve tierod.
[0006] In order that the invention be better understood and carried into practice, some
preferred embodiments thereof will hereinafter be described with reference to the
accompanying schematic drawings in which
- Fig. 1
- is a sectional view of the reducing valve;
- Fig. 2
- is a section taken along the line A-A in Fig. 1 and showing the closure of stays on
the periphery;
- Fig. 3
- is a sectional view of the reducing valve in the closed state;
- Fig. 4
- is a sectional view of the reducing valve comprising a single stay; and
- Fig. 5
- is a sectional view of the reducing valve controlled after the pressure exposure.
[0007] As can be seen in the drawings, and particularly in Fig. 1 thereof, the straight
stays 1 are in the point 2 fixedly attached to a holder 3 which is secured to the
valve body 4, the free end of the stay 1 bearing on a needle 5 which latter bears
in turn on the valve 6 of a seat 7. The stays 1, including the connection point 2,
are enclosed on the periphery by means of a fold and define thus a cavity 8 together
with a forechamber 9 air-tightly communicating with the straight stays 1, reduced
pressure outlet for a hose 10, and the valve body 4.
[0008] The valve designed for being used in respirators adapted to operate exclusively in
the superatmospheric pressure breathing regime is controlled by a straight stay or
stays 1 immediately confining a space or cavity 8. In inoperative state where the
cavity inlet is not exposed to any medium pressure, the stays 1 are tight and hold
a valve 6 open until the pressurized medium has entered therethrough the cavity 8
where a superatmospheric pressure is produced consequently. Thereby the straight stay
or stays 1 are bent, get shorter and release the valve 6 which cuts off the medium
flow. By aspirating from the apparatus, the superatmospheric pressure in the cavity
8 drops so that the stays begin to reassume their original shape and to reopen the
valve 6. The cavity 8 is air-tightly separated from the ambient atmosphere by cementing
an elastic fold onto the periphery of stay 1, which fold is followed by a sealed forechamber
9 closing the entire automatic stay system and allowing the medium to be let in and
out.
[0009] One stay 1 is asymmetrically secured by one end in the point 2 relative to the holder
3 to the valve body 4 while it bears by its other end, via the needle 5, on the valve
6 between the inlet pressure and the reduced pressure cavities 11 and 8, respectively,
the stay 1 being air-tightly joined by fold with the holder 3, and defining thus the
cavity 8 air-tightly secured to the valve body 4 and, via forechamber 9, to the reduced
pressure inlet of the cavity 8 from the ambient atmosphere.
[0010] According to a further embodiment one or two straight stays 1 controlling the valve
6 are secured to the valve body 4 at the opposite side relative to the point 2 or
joint with the holder 3 which is constituted by a tierod bearing on the valve 6 of
a seat 7.
1. A superatmospheric pressure controlled reducing valve comprising two straight stays
attached each by one end to a valve body and bearing by their opposite end on a valve
between a space of inlet pressure and that of reduced pressure,
the valve being characterized in that the straight stays (1) are connected at one end in a point (2) with a holder
(3) secured to the valve body (4), and bear by the other, free end, via a needle (5)
on a valve (6) through an inter-space or cavity (8) of reduced pressure, the stays
(1) being joined together air-tightly at circumference by a fold and defining thus
said cavity (8) which communicates air-tighly with the valve body (4) and, via a forechamber
(9), with the reduced pressure inlet, from the ambient atmosphere.
2. A valve according to claim 1, wherein one stay (1) is asymmetrically secured by one
end in the point (2) relative to the holder (3) to the valve body (4) while it bears
by its other end, via the needle (5), on the valve (6) between the inlet pressure
and the reduced pressure cavities (11 and 8, respectively), the stay (1) being air-tightly
joined by fold with the holder (3), and defining thus the cavity (8) air-tightly secured
to the valve body (4) and, via forechamber (9), to the reduced pressure inlet of the
cavity (8) from the ambient atmosphere.
3. A valve according to claim 1, wherein one or two straight stays (1) controlling the
valve (6) are secured to the valve body (4) at the opposite side relative to the point
(2) or joint with the holder (3) which is constituted by a tierod bearing on the valve
(6) of a seat (7).
