CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is the US national stage under 35 U.S.C. § 371 of International Application No. PCT/EP2019/076641 which was filed on Oct. 1, 2019, and which claims the priority of application LU 100958 filed on Oct. 11, 2018, the content of which (text, drawings and claims) are incorporated here by reference in its entirety.

FIELD

The invention is directed to the field of taps for compressed gas, more particularly to devices for regulating the pressure of compressed gas. Such devices are usually mounted on gas cylinders.

BACKGROUND

Prior art patent document published EP 1 327 804 A discloses a tap for compressed gas comprising a shut-off valve, a pressure reducer and a flow selector. The shut-off valve and the flow selector are both operated by a single hand-wheel carried by a rotatable spindle. The latter comprises a disk with calibrated holes for being selectively positioned in front of a gas passage in order to select a flow rate. The spindle cooperates also with a system that converts a rotation of the spindle into a translation for operating a shut-off valve. The conversion is based on a threaded engagement of an element with the body, the element being driven in rotation by the spindle while being able to translate relative to the spindle. The device can therefore be operated for opening the gas passage and also selecting an appropriate flow rate by rotating the hand-wheel. The inherently low pitch of the threaded engagement implies that the shutter of the shut-off valve is moved over a limited stroke when rotating the hand-wheel over a fraction of a turn. Also the shutter is downstream of the seat, meaning that a minimum force must be exerted thereon for achieving a proper shut-off of the passage. This requires a very accurate machining and mounting of the many elements thereof. Also, the pressure reducer is arranged laterally, i.e., perpendicularly to the longitudinal axis of the device, rendering thereby the device particularly bulky.

Prior art patent document published WO 96/07843 A1 discloses a device for regulating the pressure of compressed gas, comprising a pressure reducer and a flow selector. A rotatable spindle carried a hand-wheel and a disk with calibrated holes for being selectively positioned in front of a gas passage in order to select a flow rate, similarly to the preceding document. The disk comprises also a cam for pressing the piston of the pressure reducer and thereby urging the shutter thereof against the seat. This teaching is interesting in that it is more compact than the preceding one while providing a proper shut-off function. However, in case of damage to the shutter or the seat of the pressure reducer, the shut-off function might be impaired.

SUMMARY

The invention has for technical problem to alleviate at least one drawback of the above cited prior art. More particularly, the invention has for technical problem to provide a compact pressure regulating device with a safe shut-off function. Even more particularly, the invention has for technical problem to provide a compact pressure regulating device with enhanced functions, like flow selection and/or pressure selection.

The invention is directed to a device for regulating the pressure of a compressed gas, comprising: a body with a gas inlet, a gas outlet and a gas passage fluidly interconnecting the inlet and outlet; a mobile element biased by a main spring and carrying a shutter cooperating with a seat in the gas passage, the shutter and the seat forming a regulating valve, the element delimiting with the body a regulating chamber downstream of the valve and being configured to regulate the gas pressure in the chamber by varying a flow section in the valve dependent on the pressure; a shut-off valve with a shutter and a seat in the gas passage upstream of the regulating valve; an actuation assembly of the shut-off valve; wherein the shutter of the shut-off valve comprises a stem extending through the mobile element and the shutter of the element, for cooperating with the actuation assembly located in front of the element.

Advantageously, the actuation assembly is located in front of the mobile element, i.e., in vis-à-vis of a face of the element that is opposite to the shutter and seat of the regulating valve.

Advantageously, the shutter of the regulating valve is downstream of the seat of the valve. Advantageously, the main spring biases the piston such as to move the shutter of the regulating valve away from the seat of the valve.

According to an exemplary embodiment, the shutter of the regulating valve, i.e., an end thereof cooperating with the seat, has an annular cross-sectional profile and a wedged longitudinal profile.

According to an exemplary embodiment, the mobile element is a piston with a protruding portion carrying the shutter of the regulating valve, the portion and shutter comprising each a through-hole through which the stem of the shutter of the shut-off valve extends.

According to an exemplary embodiment, the stem of the shutter of the shut-off valve extends through the protruding portion in a gas tight fashion by means of a gasket between an outer cylindrical surface of the stem and an inner surface of the protruding portion.

According to an exemplary embodiment, the device further comprises a circular element with a cylindrical inner surface guided in translation in a gas tight fashion by the protruding portion of the piston and with a front surface biased in a gas tight fashion by a spring against a seat surface on the body, so as to form a pressure relief valve.

According to an exemplary embodiment, the spring of the pressure relief valve is the main spring biasing the piston such as to move the shutter of the regulating valve away from the seat of the valve.

According to an exemplary embodiment, the shutter of the shut-off valve comprises an operative portion upstream of the seat of the valve, the stem extending through the seat. The operative portion shows a flared profile configured for engaging the seat.

According to an exemplary embodiment, the seat of the shut-off valve and the seat of the regulating valve are formed on opposite sides of a seat element with a through-hole forming the gas passage and through which the stem of the shutter of the shut-off valve extends.

According to an exemplary embodiment, the body comprises a cavity with a bottom surface with the gas passage at a centre portion thereof, the seat element being held between the surface and an inner face of a disk element mounted against the surface, the seat surface of the pressure relief device being on an outer face of the element. The disk element is in various instances mounted by screwing into the cavity.

According to an exemplary embodiment, the shutter of the shut-off valve comprises a stem opposite to the stem extending through the mobile element, the opposite stem being slidable in a gas tight fashion with the body so as to end in a cavity at the ambient pressure and to compensate at least partially an effect of the inlet pressure on the shutter when in a shut-off position against the corresponding seat tending to press the shutter against the seat.

According to an exemplary embodiment, the actuation assembly of the shut-off valve comprises a hand-wheel carried by a spindle rotatable on the body, and a system for converting a rotation of the hand-wheel into a translation moving the shutter of the shut-off valve.

According to an exemplary embodiment, the system of the actuation assembly comprises a cam spigot rotatably housed in the spindle and a counter-cam spigot movable in translation but not in rotation relative to the body, and acting on the stem of the shutter of the shut-off valve.

According to an exemplary embodiment, the spindle is operatively linked to a flow selector disk with calibrated holes selectively forming the gas passage downstream of the shut-off valve. The spindle and the flow selector disk are in various instances unitary, i.e., a single piece.

According to an exemplary embodiment, the device further comprises an adjustment assembly of the regulating valve, the assembly being around the actuation assembly of the shut-off valve and being configured for adjusting the biasing force on the mobile element resulting of the spring.

According to an exemplary embodiment, the adjustment assembly comprises a system with a threaded engagement for converting a rotation into a translation, the translation adjusting a compression of a counter-spring on a face of the movable element opposite to the main spring or moving a housing on which the main spring rests.

According to an exemplary embodiment, the actuation assembly comprises a central translating rod configured for acting on the stem of the shutter of the shut-off valve and an actuation system of the rod, the system in various instances comprising a lever with a cam acting on the rod.

According to an exemplary embodiment, the converting system of the adjustment assembly comprises a rotatable element housing the central translating rod and a counter-element movable in translation but not in rotation and in threaded engagement with the element.

According to an exemplary embodiment, the rotatable element pivotally carries the lever with the cam.

According to an exemplary embodiment, the counter-element compresses the counter-spring.

According to an exemplary embodiment, the rotatable element comprises a cylindrical wall housing in a gas tight fashion the movable element and delimiting the regulating chamber, and the counter-element comprises a cylindrical wall surrounding the cylindrical wall of the rotatable element and supports the main spring.

The invention is particularly interesting in that it provides a very compact design while providing many useful functions, i.e., at least a specific shut-off valve and a pressure reducer. Also, the different elements, e.g., the pressure reducer, are all in-line, i.e., centred on the longitudinal axis of the device. This renders the machining and assembling operations easier and therefore cheaper. Additional functions such as a pressure relief valve, a residual pressure and/or a flow selector can be easily integrated. Also the pressure reducer can be adjusted while still providing a separate actuation of the shut-off valve. This is particularly useful in that once the outlet pressure has been adjusted, the device can be shut-off and reopened without any change to the setting.

The invention is also interesting in that it provides an efficient command or actuation assembly for selectively shutting-off and opening the gas passage. The cam mechanism according to the invention is particularly efficient in that it is compact, easy to manufacture, reliable and provides an improved command, essentially in that the gas passage can be fully opened by rotating the hand-wheel over a fraction of turn, e.g., less than a half turn, the rest of a turn being available for the flow selection, if any.

