Membrane safety valve.

The present invention relates to a diaphragm valve. It concerns more particularly a diaphragm safety valve to limit the pressure of a fluid.

Known safety valves for pressure compensation element. When excess fluid pressure provides an upward buoyancy whose value is greater than the downward force developed by the compensation element, the valve opens, and the fluid escapes into an annular chamber surrounding the shutter of the valve element. (See FR-A-2103729).

The use of membranes for valves using such safety valves (see for example the patent FR-A-2528932 plaintiff) is particularly advantageous. In these known safety valves the upper body comprises in the axis of the seat of the valve shutter, a cylindrical extension inside which is directly provided with a circular groove for receiving the edges of a membrane which is crimped in throat by folding an annular tab provided above it.

It is known to limit to a maximum setpoint pressure in a chamber by an assistance device for safety valve spring loaded (see for example FR-A-2115574).

These known devices have disadvantages. They require a lot of room for their achievement.

In addition, opportunities and tool wear cause imperfections dimensional pieces.

By making a series of identical pieces with a single tool, said identical parts will be a slightly different geometry.

Thus, room dimensions can not be strictly conform to their ideal theoretical geometrical definition.

The geometric variations due to these imperfections are called dispersion or technical error.

There are several kinds of dispersions.

Dimensional dispersion of parts of valves known during handling (manufacture, disassembly, assembly, etc.). This dimensional dispersion includes all the parts of each valve.

Other types of dispersions are divided between position dispersions and dispersions of orientation of the various parts of the valve.

Taking the parts of a valve at random, it is found, after mounting, a variation in intensities of the upward vertical thrust between the different assemblies of the valve; moreover, the position of the different parts (valve shutter body, annular groove, spring, membrane) with respect to the other is modified at each installation. The dispersion is such that the interchangeability of parts can be made at the cost of additional tare operation.

Some devices can not be disassembled and even in the case where removal is possible, it disrupts the valves, because of dispersions and requires a calibration operation after reassembly.

Accordingly, it is possible to note geometry variations due to different dimensions of the parts that are never strictly identical shapes and volumes. These differences in dimensions are added to or subtracted from each other resulting dispersions.

The invention aims to remedy these drawbacks. It therefore relates to a diaphragm valve for heating circuit, for example, a safety valve group supplying a cold water hot water generator storage.

This valve is characterized in that it constitutes a demountable modular element formed by at least one disk, a disk gate, a membrane, a rod, a calibration nut and a drain knob. The disk, the disk holder and the membrane are made in one piece.

The valve is incorporated into a device forming the seat.

The molded diaphragm on the valve stem is of discoid shape.

Other characteristics and advantages of the invention will appear on reading the following description and the annexed drawing which shows a longitudinal section of the valve according to the invention.

As shown the figure, the invention concerns a valve from its seat formed by a housing in a body 11 of a security group supplying a cold water hot water generator storage and a cartridge 4 which comprises a disk 1, a disk holder 2, a membrane 3, a rod 8, a calibration nut 6, a drain knob 7, a spring 5, a locking ring 9, an identification washer 10. The nut tare includes helical ramps 12 directed outwards from the body 11 of the security group; said helical ramps 12 are parallel to a cylindrical axial extension 13 of the nut 6. The calibration nut 6 comprises six PANAs 14 serving as a drive face. The helical ramps 12 are in the extension of an intersection of two of the hexagon 14.

The nut extends in the direction of the disk 1 by a threaded hollow cylinder 15 for fixing the valve body 11 of the security group.

The calibration nut 6 in the form of a hollow threaded spindle of which the operating head comprises opposite side of the thread 22:<ul><li>an operating head with hexagon 14 for use as plug in contact with a key,</li><li>a cylindrical extension 13 of a diameter less than the shortest length for joining two opposite sides 14 of said head,</li><li>at least two bosses 20 in the extension of the greatest diagonal distances from said head, the bosses 20 being of a lower height than said cylindrical extension 13.</li></ul>

Drain knob 7 includes many helical ramps 12 that the nut bosses 20.

Each helical ramp 12 cooperates with a boss 20.

The housing in the body 11 of a security group is present from the outside to the inside in the form of a threaded bore, a constriction 16 forming a stop followed by a larger diameter forming the chamber 21 which opens into a conduit 17 of smaller diameter.

Connecting the chamber 21 with the conduit 17 is capable of forming a valve seat 23, the disc 1 forming the valve.

The disk 1, the record carrier 2 and the diaphragm 3 are formed in one piece overmolded 18. The membrane 3 is flat and swingable about ten degrees by following the displacement of the rod 8. The part 18 is molded linked rigidly to the rod 8 which passes through the nut 6 by an axial bore 19 that this latter. The rod 8 has a shoulder 24 to receive one end of spring 5, which rests with its other end on the calibration nut 6. The locking ring 9 is attached to the end of the rod 8 and maintains the drain knob 7. Said drain knob 7 is guided by the cylindrical axial extension 13 of the nut 6.

The valve can be manually opened which allows an emptying of the body 1.

Manual opening of the valve is obtained by rotating the drain knob 7. The extension of this rotational movement closes the valve to the seat.

Thus the movements of opening and closing the valve guides are obtained by the same rotational movement in the same direction. It is not necessary to resort to a different direction of operation for the closure.

By the rotational movement of the drain knob 7, the helical ramps 12 pushing the drain knob 7 which moves away from the body 11 but is maintained in contact with the bosses 20 by the pressure of the spring 5 transfered to the ring 9 by through the component 18 and the stem 8.

The valve opens throughout this rotational movement of the drain knob 7, so that the helical ramps 12 remain in contact with the bosses 20.

The bosses 20 and the helical ramps 12 being of the same size, respectively, the extension of the rotational movement brings each helical ramp 12 beyond the boss 20 with which it was in contact. The pressure bosses 20 disappears, at that time the spring pressure causes the closure of the valve.

The nut is screwed in the housing, it secures the diaphragm 16 sealingly shrinkage abutment by a clamping. Under the pressure of the spring 5, Disc 1 closes off the duct 17.

The valve hydraulically security group membrane supplying cold water a hot water generator comprises at most three parts transmitting the pressure of the hot water generator to the calibration nut 6.

In effect the spring 5 conveys in the damping, the pressure fluid from the conduit 17 to the nut 6. Said pressure is transmitted to the spring 5 only via the part 18 and of the stem 8.

The valve function is performed without calibration station. Only, a precision spring 5 and a small number of elements, used to ensure the stack by calibration thereof.

Unlike the state of the prior art, the calibration does not require a post specially created for this operation, which complicated the manufacturing and especially reassembly.

The invention eliminates the operation of crimping and turn the valve in a removable cartridge valve for the calibration nut 6 is screwed into the housing provided in the body of the hydraulic safety group 11 for the positioning of the valve.

This new technology ensures the valve function by a modular element that can be incorporated into any set.

Alternatively, the membrane valve for hot water heating generator circuit constituting a modular element that can be incorporated into any set, and comprising at least a disk 1, a disk holder 2, a membrane 3, is characterized in that it comprises at least one feature as set out above.

Reducing the number of these elements allows a more reliable product in terms of quality of the various elements, so a lower number of rejected products.

The reduced number of parts decreased very strongly the dispersion, so that each assembly or reassembly of the valve according to the invention, the different parts meet the same geometry.

The oscillation, following displacement of the rod 8 of the diaphragm 3 of more or less five degrees around allows the use of a membrane of the shape of a disk and a rolling diaphragm not more difficult to manufacture and a cost higher.

The diaphragm 3 of the valve according to the invention is molded. This provides the advantage of not having to assemble components such as the rod 8, the membrane 3, the disc 1, the disc holder 2, etc ...

Thus, thanks to the small number of parts and the molded membrane that ensure reliability and consistency of the geometry, it is no longer necessary to calibrate the valve after installation during manufacture. Furthermore it can be traced back without performing calibration after a disassembly.

In addition, the reduced number of parts makes the most reliable valve especially when the parts are manufactured in series.

Furthermore, the valve according to the invention can be adjusted to a constant pressure; for example, it releases steam beyond 8.4 bar and for heating it limits the pressure to 3 bar.