* * *

DESCRIPTION

Technical field

The present invention describes a safety device for pumps .

More specifically, the present invention describes a device according to the preamble of appended claim 1.

Prior art

In the technical field safety devices, namely vent devices, are known, which have a casing comprising an inlet opening and an outlet opening for the liquid under pressure coming from a pump that is arranged outside of the device. The casing is generally manufactured using several brass components, which are coupled to one another by means of complementary threads. Generally, in correspondence to the inlet opening, there is associated a non-return valve, which is provided with a ball -shaped plug element, so as to prevent the liquid from flowing back to the pump.

Furthermore, the casing has a safety opening, which is associated with a safety or vent valve having a ball -shaped plug element, which is pushed by a compression pre-loaded helical spring. The elastic compression pre-load of said spring is duly adjusted (for example by positioning a screw or a dowel, which is able to conveniently push the spring) , so as to allow the fluid to flow through only when the liquid exceeds a predetermined threshold pressure.

A drawback that is associated with the safety devices of the known type is the use of a great number of components, which makes these devices more difficult to be assembled, thus increasing their cost.

A further drawback consists in the fact that said components are typically coupled to one another by means of complementary threads, which causes said safety devices to be more difficult to be installed.

Finally, the ball-shaped plug element offers a reduced sealing surface and, therefore, in order to adjust the opening of the safety valve to high threshold pressures (i.e. about 12 bar), helical springs with a significant length are generally used. Consequently, the use of the ball- shaped plug element causes the safety devices of the prior art to have a remarkable longitudinal size in the overall dimensions.

Therefore, the object of the present invention is to overcome the drawbacks described above, thus obtaining a safety device that is easy to be assembled, that it is not bulky and that can be produced at low costs.

Summary of the invention

The object of the present invention is to provide a safety device that is able to solve this and other drawbacks of the prior art, thus obtaining a safety device that is easy to be assembled, that it is not bulky and, at the same time, can be produced in a simple and economic way.

According to the present invention, this and other objects are reached by means of a safety device having the features set forth in appended claim 1.

The appended claims are an integral part of the technical teaches provided in the description with reference to the present invention.

Brief description of the drawings

Further features and advantages of the present invention will be best understood upon perusal of the following detailed description, which is provided by way of non- limiting example , with reference to the accompanying drawings, which specifically show what follows:

figure 1 shows a prospective view from the top of a safety device according to a first explanatory embodiment of the present invention;

- figure 2 shows a prospective view from the bottom of the safety device shown in figure 1;

- figure 3 shows an exploded prospective view of the safety device shown in the previous figures;

- figure 4 shows a vertical cross-section view of the safety device shown in the previous figures;

figure 5 shows a prospective view from the bottom of a safety device according to the present invention in a second explanatory embodiment of the invention;

- figure 6 shows a prospective view from the top of the safety device shown in figure 5;

- figure 7 shows an exploded prospective view of the safety device shown in figures 5 and 6; and

figure 8 shows a vertical cross-section view of the safety device shown in the figures from 5 to 7;

Detailed description of the invention

With reference to the figures from 1 to 4 , a safety device is shown, which is manufactured according to a first explanatory embodiment of the present invention. The safety device, which is generically indicated with reference number 1, can be associated with a pump (not shown) .

Safety device 1 comprises a casing, which comprises, in turn, a first element 2 and a second element 3, which are both preferably made of plastic. Preferably, the casing consists of the first element 2 and of the second element 3. The first and the second element 2 and 3 can be coupled to one another by means of a quick coupling device. The safety device comprises, furthermore, a non-return valve 4 and a safety valve 5 (see, in particular figures 3 and 4) .

The first element 2 comprises an inlet opening or fitting 21, adapted to receive the fluid coming from the (external) pump, and an outlet opening or fitting 22, adapted to deliver the fluid flowing into the casing through inlet opening 21 under normal conditions, namely when said fluid is subject to a pressure that is lower than a predetermined threshold pressure.

The first element 2 has, furthermore, a cavity comprising a first chamber 23 and a second chamber 24, which are adjacent to one another. In particular, the first chamber 23 is adjacent to inlet opening 21 and the second chamber 24 is adjacent to outlet opening 22. The first chamber 23 has a plurality of hollows 25, which are obtained on its inner surface.

The casing, and preferably the second element 3, has a safety opening or fitting 31 for the vent or outlet of the high-pressure fluid under anomalous conditions, namely when said fluid reaches a pressure that is higher than or equal to the predetermined threshold pressure, and a third chamber 32, which is adjacent to safety opening 31.

Preferably, inlet opening or fitting 21 and outlet opening or fitting 22 are arranged according to directions that are transverse to one another and, more preferably, said directions are orthogonal to one another.

Preferably, inlet opening or fitting 21 and outlet opening or fitting 31 are arranged according to directions that are parallel to one another and, more preferably, said directions coincide with one another.

As mentioned above, the first and the second element 2 and 3 are coupled by means of quick coupling means. In this first embodiment, the mechanical connection between elements 2 and 3 takes place by means of a coupling of the bayonet type; preferably, the first element 2 has a plurality of peripheral recesses 26 (which, for example, are obtained on the inner periphery of said first element) , and the second element 3 has a plurality of peripheral projections 33 (which, for example, are obtained on the outer periphery of said second element) , which can slide, while rotating, in the plurality of recesses 26 of the first element 2. Furthermore, a first O-ring 7 is arranged on the second element 3, so as to adhere to the inner walls of the second chamber 24 of the first element 2.

Non-return valve 4, which can be inserted into the first chamber 21 of the first element 2, is contained in a cartridge or housing member 41. Said housing component 41 has an annular structure 410, from which four curved peripheral arms 411 project in an axial direction centrally converging on an axial guide hollow body 412.

Furthermore, housing member 41 comprises an annular shoulder 414, on which annular structure 410 acts on the opposite side with respect to arms 411. Advantageously, annular shoulder 414 peripherally has a further sealing gasket 415, which, for example, is housed in a radially external peripheral recess (not numbered) and exerts a radial seal in chamber 23.

Furthermore, non-return valve 4 comprises a mushroomlike plug element 42, which has a stem 421 and a head 422, a spring 43 and a second O-ring 44. Stem 421 of plug element 42 can slide inside axial guide hollow body 412 of housing member 41, where said spring 43 is interposed. The second O-ring 44 is arranged on head 422 of plug element 42.

Furthermore, housing member 41 has a plurality of projections 413, (which can be better seen in figure 3), which, for example, are supported by arms 411 that can elastically spread apart. Projections 413 can be engaged in the above-mentioned plurality of hollows 25 obtained on the first chamber 23 of the first element 2, thus being locked therein, and, by so doing, they make it easier for nonreturn valve 4 to be inserted and locked inside the first chamber 23 of the first element 2.

Safety valve 5, which is contained in a housing portion 35 of the second element 3, comprises a mushroomlike plug element 52, which has a stem 521, a head 522 and a third 0-ring 523, an upper element 53 and a spring 54.

In this embodiment, cavity 32 is obtained in housing portion 35 and has a mouth 512, where a plurality of hollows 514 are obtained. Plug element 52 is housed in cavity 32 and between head 422 and housing portion 35 there is axially interposed a helical spring 54, which hinders the axial sliding of cut-off element 52. The spring is adjusted so as to allow safety valve 5 to open only when the pressure of the fluid flowing into inlet opening 21 exceeds a predetermined threshold value .

Upper element 53 has a plurality of protuberances 531, each of which is able to be inserted into a respective hollow 514 of seat 512, thus being coupled, by means of a bayonet coupling, to housing portion 35, so as to prevent plug element 52 from coming out in an undesired manner.

With reference to the figures from 5 to 8 , a safety device is shown, which is manufactured according to a second explanatory embodiment of the present invention. The safety device is identified, as a whole, with reference number 1 ' .

In this embodiment, the components that are the same as those of the previous embodiment are numbered with same reference numbers and, for the sake of brevity, are considered as already described.

Safety device 1' mainly differs from the one described above in the coupling system between the first element 2 and the second element 3 and in the shape of safety valve 5 ' .

The connection between the first element 2 and the second element 3 takes place by means of coupling means, namely by engaging a fork 6, whose arms 61 are inserted into a plurality of holes 27 obtained on the first element 2, thus fitting into a groove 34 obtained in the second element 3. Therefore, the two elements 2 and 3, in this way, are locked in an axial direction.

Safety valve 5 ' , which is housed in the third chamber 24 of the second element 3, is contained in a cartridge or housing member 51', which is substantially similar to cartridge or housing member 41 of non-return valve 4.

In this embodiment, housing member 51' has an annular structure 510', from which four curved peripheral arms 511' project in an axial direction centrally converging on an axial guide hollow body 512' .

Furthermore, housing member 51' comprises an annular shoulder 514', on which annular structure 510' acts on the opposite side with respect to arms 511'. Advantageously, annular shoulder 514 ' peripherally has a further sealing gasket 515', which, for example, is housed in a radially external peripheral recess (not numbered) and exerts a radial seal in chamber 32.

Safety valve 5' comprises a mushroom-like plug element 52', which has a stem 521' and a head 522', a spring 53' and a third O-ring 54'. Stem 521' of plug element 52' can slide inside the axial guide hollow body 512' . A spring 53' is interposed between plug element 52 ' and hollow body 512'. The third O-ring 54' is arranged on head 522' of plug element 52 ' .

Furthermore, housing member 51' has, on arms 511', which can elastically spread apart, a plurality of projections 513', which are able to be engaged in a plurality of hollows 35' obtained on the third chamber 32 of the second element 3, thus being locked therein, and, by so doing, they make it easier for safety valve 5 to be inserted and locked inside the third chamber 32 of the second element 3.

A first advantage of the safety device according to the present invention is the use of plastic material, which allows the number of the components to be reduced, thus allowing cost reduction.

A further advantage is the extreme simplicity with which the device can be assembled, which is guaranteed by the reduced number of components an by the easy coupling systems .

Furthermore, a further advantage consists in the fact that the mushroom- like plug element, given the same elastic force, offers a smaller longitudinal size of the safety device, thanks to the use of a spring with a smaller length, due to the larger extension of the sealing surface of the O-ring in the head of the plug element.

Naturally, the principle of the present invention being set forth, the embodiments and the implementation details can be widely changed with respect to what described above and shown in the drawings as a mere way of non- limiting example, without in this way going beyond the scope of protection provided by the accompanying claims.

In particular, as a person skilled in the art can appreciate in the light of the present description, the different technical features of the different versions of the embodiments described and illustrated above are freely exchangeable, if possible. By mere way of non exhaustive example, in further embodiments (not shown), a person skilled in the art, in the first embodiment, can replace safety valve 5 with safety valve 5 ' shown in the second embodiment, and vice versa.