CH258665A - Non-return valve, in particular for compressors. - Google Patents

Description

Non-return valve, in particular for compressors. The invention relates to automatic check valves and it relates more particularly, but exclusively, among the valves, to those designed to be mounted in a gaseous fluid compressor such as an air compressor.

Valves of the indicated type are already known having at least one closure element in the form of an elastic laurel capable of undergoing deformations between a seat and a butt surface Ae, in order to open, under the influence of a Pressure difference, uu passalte convergent-divergent, for the fluid which will have to pass through the valve, while the valve takes its closed position, under the influence of its own elasticity, when there is no pressure difference between its opposite sides.

The object of the invention is to improve the above known valves.

The valve according to the invention is characterized in that at least one additional elastic laurel is juxtaposed to said closing laurel.

0n thus obtains a valve capable of operating correctly, in 1 es, difficult conditions. as they occur in high speed compressors; that is to say having a large number of oscillations even unit of time, and this for long periods, except that the valve requires monitoring and without which gives rise to leaks. annexes represent several forms of execution of the object of the invention and this by way of example.

fig. 1 shows a first form of execution in section, the part situated to the left of the line A-A being a section along the line IL-IL of FIG. 2, and the part of fig. 1 located to the right of the line A-A being a section along the IR-IR line of FIG. 2.

fig. 2 is a section: along line 2-2 of FIG. 1.

fig. 3 shows a sectional detail along line 3-3 of FIG. 1.

fig. 4 shows another detail in section, along line 4--4 of FIG. 2.

Figs. 5 and 6 show in perspective, respectively a side element and an intermediate element of the valve represented by FIGS. 1 and 2, Ges elements bearing surfaces which form the valve seat.

fig. 7 representations, ente in perspective a thrust plate of the same valve.

Figs. 8 and 9 show in perspective, respectively, a closing lavra and an auxiliary lavra of the valve in question.

fig. 10 shows in section an RTI ID="0001.0269" WI="10" HE="4" LX="1691" LY="2032"> Part of a valve established according to another embodiment of the invention.

The figs. 11 and 12 show in perspective a lateral element and an intermediate element of the valve represented; entered in FIG. 10, these elements bearing. valve seat surfaces.

fig. 13, finally, shows in perspective an auxiliary lavra of the valve represented by fig. 10.

The valve shown in Figs. 1 to 9 comprises two side members 10 which carry surfaces 13 which form valve seats and between which a certain gap is provided. Between the elements 10 there are intermediate elements 11 which also carry surfaces 13 constituting valve seats and whose number can be chosen as desired. A buttress plate 12 is arranged between each pair of two adjacent elements 10 or 11. The surfaces 13 of the elements constituting the valve seats are planar. The seats arranged opposite each other and forming a pair of seats move away from each other in the direction of the flow of fluid. The lateral elements 10 are provided, near the inlet end of the valve, with two bosses 14" and the intermediate elements, 11 also comprise two bosses 15. These bosses serve for the passage of bolts and their surfaces are flush with the plane seats 13. Further, each of the side members 10 is provided with an intake port 16 which extends across the inlet edge 17, between the bosses 14, and over a substantial portion of the surface 13.

Each intermediate element 11 is constituted by a transverse part 18 and by two end parts 19, the latter extending from the bosses 15 to the transverse part 18. The space comprised between the bosses and the said end parts constitutes the inlet port which is common to both valve seats of the intermediate element.

Between each seat element 10 or 11, on the one hand, and the abutment plate 12, on the other hand, are arranged: 10 a spring steel laurel 20A which rests flat on the seat surface 13, and 20 an auxiliary laurel 20B which presses against the thrust plate when the valve is open. The entry edge of each abutment plate 12 has a wedge-shaped section, the angle of this wedge corresponding to the divergence of two adjacent seats 13. The two series, located at the two ends of the valve, -of bosses 14 and 15 as well as holes made in the Stop plates 12 and in the blades 20A, 20B are traversed by tension bolts 21 which tighten firmly. each pair of laurel by their inlet end between, on the one hand, a pair of bosses 14 or 15 and, on the other hand, the adjacent edge of an abutment plate. At the same time, they lock the parts of the valve in their desired mutual position.

The valve body is completed by two identical terminal RTI Plates 22 which are fixed to the side members 10 at the seats. . The fixing of the end plates is obtained by means of screws and a dowel which engage, respectively, in the threaded holes 35 and in a dowel hole 36 (see fig. 5) provided in each of the side elements with seat. . The Edges of the blades at the inlet end of the valve between the bosses are fixed to the Stop Plates 12 by means of: others being secured by rivets 24 which pass through the blades and the stop plates. The intermediate side seat members are provided with langitudinal prongs 25 and 28, the edges of these prongs being located in the plane of the seat surfaces; these prongs serve to support the blades at the intake ports when the blades are in the CLOSED Position.

The Thrust Plates 12 can be fastened directly to the End Plates 22 by means of screws 2.9 and dowels 30 (see Fig. 3) which serve to transmit to the valve body the thrust which, thanks to the difference - Pressure reference taking place in the fluid during its passage through the valve, acts on all of the intermediate elements: the seats, the thrust plates and the blades. Said screws and studs also serve to prevent lateral displacement of the outlet ends of the Stop Plates.

In the example described, the closing blades 20A are flat as long as they are not subjected to an external constraint (see FIG. 8). On the other hand, the auxiliary blades, when they are free from any external constraint, are concave on that of their sides which is opposite the seat (see fig. 9). The closing blades are made of spring steel having a thickness between 0.15 and 0.3 mm and a length of about 27 mm measured between their fixed edge and their free edge. The auxiliary blades 20B are also made of spring steel sheet having a thickness between 0.15 and 0.3 mm, but their length is a little less than that of the closing blades, however at least equal to two-thirds of the length of the closing slats. In addition, the auxiliary blades have small, shallow protrusions obtained by stamping. These protrusions are found from the convex surface of each auxiliary laura and are uniformly distributed in an area which extends from the free edge of the laura for only a fraction of the height of the last laura. They are intended to facilitate the exit and the entry of the fluid Jans 1'espace located between said laure and the surface of the abutment (see fig. 9). The auxiliary blades have a uniform curvature from one. line, which corresponds to the inner edge of the binde 23 of reinforcement, to their free edge. This curvature corresponds to the surface of the segment of a cylinder whose axis is parallel to the fixed and free edges of each laure. The curvature of the auxiliary blades is chosen so that, when they are free from any external constraint, a tangent applied to the fixed edge of the lavra has a distance of 1.2 to 2.5 mm from the free edge of rette laure. This distance is indicated by T' Jans in fig. 9. The auxiliary laurel has the effect of preventing or at least lessening the tendency of the closing laurel to stick to the abutment surface when the valve is to close. In addition, the auxiliary lavra cushions the destructive shocks that would occur when hammering the closing lavra against its seat. The presence of the auxiliary lavra therefore increases the duration of the valve and reduces the risk of a break in the closing lavra.

Either an is content to proceed as described above, or, and better, an has recourse, in addition, to Pune auRTI ID="0003.0275" WI="9" HE="4" LX="1106" LY="581"> minus the following provisions: One of these provisions is intended to increase the life of both the blades and the intermediate elements with valve seats.

It is known from experience that the blade breakage angle, of angar which is particularly high for the free corners of the blades, in particular for their corners located in the vicinity of the outlet end of the valve, can be decreases if an gives the surfaces constituting the valve seats a relatively wide width, that is to say if an chooses the area relatively wide. mutual overlap between the valve seat element and the valve.

A wide seat width, however, can throttle the flow of fluid flowing through the valve, so that the last valve efficiency is reduced.

According to the arrangement in question, at the end portions of the intermediate seat element, seen in a direction normal to the surface of one of the seats, a width which increases from the bosses to, bolts 15 to the transverse portion 18. In this way, on the one hand, one obtains, for the free corners of the blades, seats which are wide enough to substantially reduce the risk of destruction of the res blades and, on the other hand , an reinforces the seat elements in places which would otherwise have a rather weak section. Finally, it retains near the inlet end of the valve where the blades, even in their fully open position, only slightly deviate from the seats, a fairly narrow seat width, of So that. unlike what would occur for wide seats, the flow of fluid through the valve is not significantly restricted.

One embodiment of this latter arrangement is represented by los fig. 2 and 6. According to these figures, the width of the end portions 19 of the intermediate elements 11 to 6 increases from a minimum A which is located in the vicinity of the bosses 15 until it reaches a considerable width B which is is where the end portions 19 join the transverse portion 18 of the intermediate element. It should be noted that, at location A, the thickness of the End Parts in a direction normal to the plane of FIG. 2 is relatively high, whereas this thickness is relatively small at the right side B. The section of the end parts at this last place would be very small if the width of the plane of FIG. 2 was at the place <I>A la</I> same quo Gelle at the place <I>B.</I>

The aforesaid construction of the intermediate elements to Seats has, moreover, the effect of ensuring a considerable width of seat to the closing blades 20_A, close to their corners, that is to say at a place where the blades s significantly apart (distance D shown in fig. 1) from the Seats, when the valve is completely open; on the other hand, the seat width E is only relatively small, ä, in the right direction where the slats deviate only slightly (distance d represented by FIG. 1) from their seats.

Furthermore, it is ensured that the channel-shaped part of the intake port, which is located between the end part 19 of the seat element and the adjacent fork, extends less far towards the outlet end of the valve than the other channel-shaped portions of the inlet port;therefore the seat width in front of the free corners of the laurel is increased also in the direction of the flow of the valve. fluid.

In this way, the danger of damage to the free corners of the blades is considerably reduced without at the same time increasing the resistance which the valve offers to the movement of the fluid passing through it. Furthermore, the element ä. seat which can be obtained by a Die-casting process can, in this way, obtain a high mechanical resistance which makes superfluous the application of reinforcing ribs which would extend from one of the End Parts to the other and which would have for effect of partially obstructing the inlet openings of 1a. valve.

The seating surfaces of the side elements have a shape similar to that of the seating surfaces of the intermediate elements, also in order to reduce the danger of damage to the blades which coact with the RTI ID="0004.0270" WI="14" HE="4" LX="1362" LY="774"> side elements to Seats.

In the event that a prong 28 of an intermediate valve seat element is fairly close to an end part 19, a rib 26 may be provided between said prong and said part. However, the provision of such a rib is not essential.

The various dimensions of the valve represented by figs. 1 to 9 may be the following, the dimensions being given by way of example and without any restrictive effect: C = 5.0 mm E = 3.0 mm D = 2.0 to 2.5 mm The clearance between the edges of the blades and the end plates 22 can be of the order of 0.05 mm.

The closing slats, instead of being flat when they are free from any external constraint (see fig. 8) can be curved, as are the auxiliary slats. In this Gas, their assembly must be carried out in such a way that their curvature tends to press them against their Seats.

The valve represented by fig. 10 to 13 has a construction similar to Gelle of the valve described above. The parts represented by figs. 10 to 13 which correspond to certain parts represented by figs. 1 to 9 are designated by the same reference numerals provided with a letter A.

Selan los fig. 10 to 13, the auxiliary laurel 20C acts as a shock absorbing plate; this is why this lavra is interposed between the corresponding closing strip 20A and the element adjacent to the seat. The 20C blade is made of spring steel sheet and has a thickness of between 0.125 and (<B>)</B>.25 mm. Its profile corresponds to the contact area which, without the strip 20C, would exist between the closing strip, on the one hand, and the surfaces forming the seat, the bosses and the prongs of the seat element, on the other. go. The blade 20C is provided with an opening 32 through which bars which correspond to the prongs 25A or 28.1; this shock-absorbing plate increases the duration of the closing blade by the slowing down that the latter undergoes when it hits the shock-absorbing plate, which takes place immediately before the moment when the. closing blade is stopped by the seat.

The slats <I>20AA</I> and also the slats 20C are formed in pairs from a flat sheet which has been given, by bending, a hairpin-shaped section. The prongs 25A which support the blades and which form part of the side elements with seats 10A, as well as the corresponding prongs 28A of the intermediate elements with seats 11.i1 are extended to the inlet end of the valve. At the fold of the. auxiliary blade 20C, cutouts 33 (fig. 10 and 11) have been made in the four chons and the bosses provided on one of the two seat elements which are located on either side of each stop plate, while the prongs and the bosses of the other element are provided with heels 34 which engage in the cutouts 33 to apply the fold of the pairs of blades 20AA and 20C firmly against the edge of the. thrust plate 12A.

It has been found in practice that, in valves of the type described above and having a plurality of passages arranged side by side, the closing blades which coact with the two side seat elements more easily lose the required tightness, when the valve is subjected to strenuous working conditions than the. closing slats which interact with the intermediate elements with seats. This may be due to the fact that the side seat elements are more rigid than the intermediate seat elements. To remedy this unequal distribution of fatigue, .one gives, according to another provision, the inlet passages 16 or 16A. which are provided in the side elements with seats, a section smaller than that which is provided for each valve seat, in the intermediate elements. This softens the working conditions for the two end closing blades. To this end, the depth (measured in the direction of the traction bolts 21 or 21A) of the passages 16 or 16A is reduced.

Of course, a shock absorber plate as shown in FIGS. 10 to 13 can be used in combination with an auxiliary blade arranged behind the closure blade, as has been shown in FIGS. 1 to 9. In addition, each of the blade combinations described above can be used, both in a valve having separate blades (fig. 1 to 9) and in a valve having blades obtained in pairs at the same time. using the bending of a common sheet.

Claims (12)

CLAIM Check valve, in particular for com pressors, having at least one iron element in the form of an elastic blade suscepti ble to undergo. deformations between a seat and an abutment surface, in order to open, under the influence of a pressure difference, a convergent-divergent passage, for the fluid which will have to pass through the valve, while the blade takes its position closure, under the influence of its own elasticity, when there is no pressure difference between its opposite faces, and characterized in that at least one additional elastic strip is juxtaposed to said closure strip. SUB-CLAIMS: 1. Valve according to claim, characterized in that the additional blade is arranged between the closing blade and the corresponding abutment surface. 2. Valve according to claim, charac terized in that the length of the additional blade measured from its fixed edge to its free edge is at least equal to two thirds of the length of the closure blade, while the widths of the blades are substantially the same. 3. Valve according to claim, charac terized in that the additional blade, when it is free of any external constraint, is curved in such a way that it turns its concave surface towards the seat which is flat. 4. Valve according to claim and sub-revenâication 3, characterized in that the closing blade is flat, when it is free of any external constraint. 5. Valve according to claim, charac terized in that the additional blade is provided, on its surface which is turned towards the abutment surface, with irregularities intended to facilitate the exit and the re-entry of the fluidr: in the space located between said blade and the abutment surface. 6. Valve according to claim and sub-claim 5, characterized in that the additional blade has shallow stamped protrusions distributed in a zone which extends from the free edge of the blade over only a fraction of the height & the latter. 7. Valve according to claim, charac terized in that the closing blade coacts directly with the seat, while the additional blade is on the opposite side of the closing blade. 8. Valve according to claim, charac terized in that the seat is covered by an additional blade in which is provided an opening which is opposite the intake port formed in the surface forming the seat. 9. Valve according to claim, characterized in that it has at least one intermediate seat element and that the width of the end parts of this element, seen in a direction normal to the seats, increases in the direction from the bosses of said element, which are intended for the crossing of traction bolts, towards a transverse part of this same element. 14. Valve according to claim, characterized in that it has at least one intermediate seat element comprising two end parts, a transverse part joining together the said end parts and .prongs suspended on the transverse part and arranged in the 'gap between the parts, end, to support the my, when the valve is closed, and that each of the end parts of the intermediate elements is braced by a rib which extends between said end parts and the neighboring fork. 11. Valve according to claim, characterized in that its seat elements comprise bosses and prongs, the latter extending towards the inlet end of the valve and serving to support the flexible blades of the valve and that the bosses and prongs of one of two neighboring elements are provided, in the vicinity of the inlet end of the valve, with cutouts in which the heels provided on the prongs and the bosses of the valve engage the other seat element forming part of said pair, the inner surfaces of these heels extending below the fold formed by a sheet of folded sheet metal, so as to have a hairpin-shaped section and to form a pair of blades. 12. Valve according to claim, characterized in that it comprises side elements with seats and intermediate elements with seats, each of these elements being provided with a passage for the admission of the fluid and that the passages formed in the side elements seats have a section smaller than that of the passages provided in the intermediate elements for each of the valve seats that comprise these latter elements.