GB1574489A

GB1574489A - Shut-off flap valve

Info

Publication number: GB1574489A
Application number: GB4462177A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-10-27
Filing date: 1977-10-26
Publication date: 1980-09-10
Also published as: FR2369480B1; FR2369480A1

Description

(54) SHUT-OFF FLAP VALVE (71) I, JOSEF NEMETZ, a citizen of the German Federal Republic, of von Bergmann-Strasse, 39, 6200 Wiesbaden Bierstadt, German Federal Republic, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a shut-off flap valve for service pipes with a flap mounted pivotably in a valve housing which flap is, in the closed position of the valve, in contact with the interior of a sealing lip on an inwardly oriented encircling flange of a seal lining arranged in the housing and made of plastics material, e.g. polytetrafluoroethylene, and with bracing rings arranged on both sides of the flange, between which bracing rings and the housing the seal lining is disposed.

The subject matter of the present invention is related to that described and claimed in my prior Patent 1,383,349 and in the Specification of my prior Application 25001/77 (Serial No. 1572436).

In the chemical industry, and also in other fields, plastics materials which are inelastic or only slightly elastic, such as polytetrafluoroethylene, but also others, are being used increasingly as sealing materials and linings. Due to the lack or comparative lack of elasticity, the customary constructions such as are used e.g. for seal linings made of highly elastic materials, are inappropriate for these plastics materials.

The known shut-off flap valves with interior lining of such a plastics material, more particularly polytetrafluoroethylene, are therefore provided with an inserted O-ring or elastomer ring in the sealing region. These constructions dictate a high opening and closing torque and only ensure adequate fluid-tightness of the shut-off flap valve at low pressures.

It is the aim of the present invention to produce a shut-off flap valve with a seal lining made of plastics materials, e.g.

polytetrafluoroethylene, which ensures adequate fluid-tightness of the shut-off flap valve even at high pressures.

According to the present invention there is provided a shut-off flap valve for service pipes and the like having a flap mounted pivotably in a valve housing which flap, in the closed position of the valve, buts against the inside surface of an inwardly concavely curved sealing lip, having oppositelydirected free edges, of a radially inwardly oriented encircling flange of a seal lining made of a plastics material arranged on the housing, and having bracing rings arranged on both sides of the flange, between which bracing rings and housing the seal lining is placed, wherein in the open position of the valve the internal diameter of the inside surface of the curved sealing lip perpendicular to the axis of the shutoff flap valve and parallel to the pivot axis of the flap is slightly less than the diameter of the flap perpendicular to the axis of the shut-off flap valve and parallel to the pivot axis of the flap, and by the provision, in the open position of the valve, of (a) a gap between the housing, or a member adjacent to the housing, and the seal lining and (b) a gap between the sealing lip and each bracing ring, the sealing lip is adapted to yield with respect to the closing movement of the flap to accommodate the flap to permit the flap to abut against the inside surface of the sealing lip to close the valve. Preferably the seal lining is made of a substantially inelastic plastics material.

The material for the seal lining and/or one or more other parts may be a polymer derived from a fluorohydrocarbon, e.g.

polytetrafluoroethylene.

When the flap is closed the said curved sealing lip, against which the flap strikes, yields and is urged in the housing direction.

When the flap is in the closed position, sealing lip portions on both sides of the seal lining are in contact with the outer peripheral surface of the flap. The outer peripheral surface of the flap is then conveniently convex and the inner peripheral surface of the coherent sealing lip on both sides is conveniently concave. It is also advantageous to round off or bevel off etc., the peripheral edges of the flap in order to ensure that the flap can, during the closing movement, urge the corresponding sealing lip towards the housing without difficulties. When the flap is closed, the service pressure presses upon the surface of the sealing lip remote from the flap and urges it against the flap.The fluidtightness of the shut-off flap valve according to the invention is therefore independent of the service pressure of the fluid medium, simply because the pressure of the fluid medium serves to press the sealing lips against the flap.

In a convenient embodiment of the invention, a gap remains, in the open position of the flap, between the housing and an annular part of the seal lining and also between the surfaces of the bracing rings confronting the seal lining and the surface of the sealing lip remote from the flap.

The said gaps are so dimensioned in practice so that the seal lining can yield sufficiently far radially when the flap is closed. When the flap is closed the seal lining presses back by its own tension and presses the sealing lip against the flap.

Fluid medium penetrates into the gap between the bracing ring and sealing lip on the corresponding side and urges the sealing lip against the flap. The gas volume enclosed between housing and seal lining then serves as additional spring means.

The enclosed gas is compressed during the closing operation and urges the sealing lip additionally towards the flap.

If the flange of the sealing lining is provided with an annular groove open towards the housing, the annular groove being interrupted by the means pivotably mounting the flap, then it is possible to conform the shut-off flap valve in such a way that there is also substantially no gap between housing and most of the annular part of the seal lining in the open position, but there will be a significant gap between the mutually confronting surfaces of bracing rings and sealing lip. In this case two side walls of the flange and/or of the groove will generally be reduced in thickness. Due to the reduction in thickness of the two side walls of the flange of the seal lining, the flange of the seal lining executes a bellows-like movement with the sealing lip during closure of the flap, whilst the corresponding portion of the sealing lip yields until the flap occupies the closed position.

Preferred means for pivotably mounting the flap comprises a pair of journals.

Several forms of the invention are illustrated in examplary manner by embodiments illustrated by Figures 1 to 15.

Figure 1 shows a half of a vertical section through a first form of shut-off valve taken at right angles to the axis of rotation of the flap, the housing exhibiting a strap; Figure 2 shows a vertical section (as taken in Figure 1) of a second form of shut-off valve similar to that shown in Figure 1, wherein housing has a differently conformed strap; Figure 3 shows a vertical section (as taken in Figure 1) of a third form of shutoff valve similar to that shown in Figure 1 through a shut-off flap valve with a housing without a strap; Figure 4 shows a vertical section (as taken in Figure 1) of a fourth form of shut-off valve similar to that shown in Figure 1 through a shut-off flap valve, the housing of which exhibits a strap, but the seal lining of which is differently conformed;; Figure 5 shows a vertical section (as taken in Figure 1) of a fifth form of shutoff valve similar to that shown in Figure 3, but with a different conformed seal lining; Figure 6 show a half of a section through a sixth form of shut-off valve taken parallel to the axis of rotation of the flap; Figure 7 shows a part of a section (as taken in Figure 6) of a seventh form of shut-off valve similar to that shown in Figure 6 but with a differently conformed seal; Figure 8 shows a detail of an eigth form of shut-off valve seen in vertical section (as taken in Figure 1) and similar to that shown in Figure 3; Figure 9 shows part of a section of a ninth form of shut-off valve with a differentialy conformed seal to that shown in Figure 6, the section being taken parallel to the axis of rotation of the flap; ; Figure 10 shows a part of a section of a tenth form of shut-off valve with a differently conformed seal to that shown in Figure 6, the section being taken parallel to the axis of rotation of the flap; Figure 11 shows a part of a section of an eleventh form of shut-off valve with a different conformed seal to that shown in Figure 6, the section being taken parallel to the axis of rotation of the flap; Figure 12 shows part of a vertical section taken at right angles to the axis of rotation of the flap of a twelfth form of shut-off valve analogous to the embodiment shown in Figures 2 and 5 but with a ring inserted into the seal lining; Figure 13 shows part of a vertical section (as taken in Figure 1) of a thirteenth form of shut-off valve analogous to the embodiment shown in Figure 5 but with an inserted seal ring;; Figure 14 shows a section (as taken in Figures 9 to 11) of a fourteenth form of shut-off valve but with a differently conformed seal to that shown in Figure 6, and Figure 15 shows a section (as taken in Figure 14) with a differently conformed seal to that shown in Figure 6.

In the embodiment according to Figure 1, the flap 3 is mounted pivotably in the housing 4. In the closed position, the flap 3 is in abutment with its external peripheral surface against the inside of sealing lip 1 arranged on the free end of an inwardly oriented encircling flange 11 of a seal lining 6 arranged in the housing 4. Bracing rings 7 are located on both sides of the flange 11. The bracing rings 7 are in abutment by their mutually confronting sides against the flange 11 of the seal lining. The seal lining 6 is placed with the annular part 5 between the bracing rings 7 and the housing 4. On both sides of the housing 4, the seal lining 6 has outwardly oriented encircling flanges 37 which lie in corresponding recesses in the housing 4.In the open position of the valve the internal diameter of the inside surface of the curved sealing lip 1 perpendicular to the axis of the shut-off flap valve and parallel to the pivot axis 14 of the flap 3 is slightly less than the diameter of the flap 3 perpendicular to the axis of the shut-off flap valve and parallel to the pivot axis 14 of the flap 3. The seal lining 6 consists of a substantially inelastic plastics material, such as polytetrafluoroethylene.

Nevertheless, in order to ensure that the flap 3 can be closed without the need to exert excessive force. and without the sealing lip 1 being damaged or even destroyed, the sealing lip 1 is arranged yieldingly, namely so that it can yield radially. The seal lining 6 is therefore arranged in such a way, that, in the open position of the flap 3, a gap 8 remains between the mutually confronting surfaces of the annular part 5 of the seal lining 6 and of the housing 4 and a gap 9 remains between the surfaces of the sealing lip 1 remote from the flap 3 and the surface of the bracing rings 7 confronting them. Both gaps 8 and 9 are dimensioned so that the sealing lip 1 against which the flap 3 strikes can yield sufficiently radially. If the flap 3 is now closed, the seal lining 6 is urged towards the housing 4 by the closing force acting upon the flap 3.The tensioning force of the seal lining 6 then urges the sealing lips against the flap 3. The gap 9 between the bracing rings 7 and sealing lip 1 should be so dimensioned that it always remains open, so that when the flap 3 is closed fluid medium penetrates into the gap 9 and acts upon the surface of the sealing lip 1 remote from the flap 3 and urges it against the flap 3. It is thus achieved that the shut-off flap valve is always adequately fluid-tight in the closed position completely irrespectively of the service pressure, because not only the tensioning force of the annular parts 5 of the seal lining 6, but also more particularly the service pressure, serves to urge the sealing lip 1 against the flap 3. The gas volume enclosed in the gap 8 becomes com pressed during closure of the flap 3.The pressure generated in the gap 8 by the compression serves additionally to urge the sealing lip 1 against the flap 3. It is also possible to fill the gap 8 with a liquid.

To compress the liquid requires a higher force, which then additionally urges the sealing lip 1 against the flap 3. In order to facilitate the opening and closing of the flap 3, it is advantageous to conform the interior of the two end portions of the lip 1 convexly and the external peripheral surface of the flap 3 concavely. It is further advantageous, in order to prevent damage to the inner free edges 2 of the sealing lip 1, to bevel or round off the peripheral edges 40 of the flap 3. The surfaces of the bracing rings 7 confronting the annular parts 5 of the seal linings 6, are con veniently inclined towards the flange 11 so that the gap 8 between annular part 5 and housing 4 widens from the outside inwards. In this way the yieldability of the seal lining 6 is increased. Seals 41 may further be arranged between the flanges 37 of the seal lining 6 and the housing 4.

In order to ensure that the medium cannot penetrate between the bracing rings 7 and the flange 11 of the seal lining 6, it is con veniently to provide the mutually con fronting surfaces of the bracing rings 7 with a groove and to insert into the latter a seal ring 10, conveniently an O-ring, which abuts against the flange 11 of the seal lining 6. It is furthermore possible to provide a groove also in the surface of the bracing rings 7 confronting the annular part 5 of the seal lining 6 at the end remote from the flange 11 of the seal lining 6 and to arrange a seal ring 42, likewise preferably an O-ring, therein (Figure 1 left-hand side).If the bracing rings 7 also consists of a substantially inelastic plastics material such as polytetrafluoroz ethylene then it is possible to conform the end of the bracing rings 7 which projects between annular part 5 and sealing lip 1 likewise as a sealing lip 13 which is in contact with the seal lining 6 and the free end of which is directed towards the sealing lip 1 (Figure 1 right-hand side). In order to improve the yieldability of the seal lining 6 in the region of the flange 11, it is possible to provide the flange 11 an annular groove 15 open towards the housing 4, which groove 15 is interrupted by journals 14. Polytetrafluoroetheylene tends to flow under high pressure and at high temperature.In order to ensure fluid-tightness even in this case, it is possible to provide the housing 4 with an inwardly oriented annular strap 17 which likewise is interrupted by journals 14, engages in the groove 15 and is in contact with the side walls 16 of the groove 15 on both sides.

In order to ensure the radial yieldability of the seal lining 6 in this case also, there is between the free end of the strap 17 and the base of the groove 15 a gap 18 which corresponds in height to the gap 8.

The flanges 37 on the seal lining 6 should project slightly laterally with reference to the housing 4. In this case there advantageously remains between flanges 37 and the surfaces of the housing 4 confronting the same a gap into which the seals 41 project. If now a pipe or the like is screwed onto the housing 4, the flange 37 is urged into the gap and the seals 41, conveniently made of an elastomer, are compressed, whereby the security of the seal is improved. In the case of the bracing rings 7 it is also advantageous to bevel the edge remote from the housing 4 between flange 37 and annular part 5 of the seal lining 6 and to provide the bracing ring 7 here with an attachment 43 which is in contact against the bevelled part by its surface confronting the seal lining 6 (right-hand side in Figure 1).When the valve is connected to service pipes etc., the attachment 43 urges the seal lining 6 against the housing 4, which leads to a sealing against media acting from the side between bracing rings 7 and annular parts of the seal lining 6.

In the embodiment of Figure 1, the housing 4 must be in two parts to enable the seal lining 6 to be inserted into the housing 4. The division of the housing is then made parallel to the flow direction.

The two housing parts are then screwed together in manner known per se.

However, if desired it is possible to conform the housing 4 and/or the seal lining 6 in such a way that the housing can also be made integral.

In the embodiment according to Figure 2 the encircling annular strap 17 of the housing 4 consists of at least two partannular segments 21, which are interrupted by the journals 14 (shown in Figure 1) and project into the groove 15. The ring segments 21 are anchored in a shallow groove in the housing 4. Should the seal lining 6 possibly become slightly heated, it becomes plastic. The ring segments 21 are inserted into said seal lining. The encircling flange 37 of the seal lining can be folded so that they lie in a plane with the annular part 5 of the seal lining 6. The seal lining can now be inserted, with the part-annular segments 21, into the housing 4 without particular difficulty. The one encircling flange 37 is then folded up again.In this case it is convenient, in order to facilitate the folding of the flanges 37, to provide the edges between the flanges 37 and the annular part 5 of the seal lining 6 with a channel 38 inside or outside, conveniently outside. In the embodiment according to Figure 2 there is arranged, as seal means between the bracing rings 7 and the seal lining 6, in the surface of the bracing rings 7 remote from the sealing lips 1, and at a short interval from the flange 11 of the seal lining 6, a groove into which a yieldable seal ring 12, more particularly an O-ring, is inserted. The interval between the seal ring 12 and the flange 11 of the seal lining 6 must then be shorter than the length of the sealing lip 1 from the free edge to the flange 11.It is thus ensured that the sealing lip 1 is urged onto the outer peripheral surface of the flap 3 by the services pressure and not the seal lining towards the housing 4, which would lead to a lifting of the sealing lip 1 from the flap 3. This mode of sealing between bracing rings and seal lining can obviously also be adopted for other embodiments of a shut-off flap valve. The reference numerals not separately mentioned here conform, like those in the following figures to those in Figure 1.

In the embodiment according to Figure 3, the housing 4 has no strap 17 (as shown in Figures 1 and 2) and no part-annular segments 21 (as shown in Figure 2) are provided. The lateral forces acting upon the seal lining due to service pressure and/ or the opening or closing moment, are absorbed by the bracing rings 7. The seal lining 6 also exhibits no outwardly oriented flanges 37. However, the bracing rings 7 have outwardly oriented encircling flanges or attachments 39 which lie in corresponding recesses on the housing 4. The seals 41 are arranged in corresponding grooves in the housing 4 between housing 4 and the flanges 39. In this embodiment, the seal lining 6 is first of all inserted into the onepiece housing 4, then the bracing rings 7 are pushed in from both sides until the mutuallly confronting surfaces of the bracing rings 7 are in abutment against the flange 11 of the seal lining 6. Ends 44 of the annular part 5 of the seal lining 6 are angled obliquely outwards. The corresponding edges of the housing 4 and the angles between bracing rings 7 and their flanges 39 are bevelled correspondingly to the angling 44 and abut with the bevelled part against the angled part 44.

The embodiment according to Figure 4 is analogous to the embodiment according to Figure 1. However, the annular part 5 of the seal lining 6 is also in abutment with the housing 4 and the bracing rings 7 on both sides in the open position of the flap 3. The strap 17 is of tear-shaped construction and the side walls 16 of the flange 11 of the seal lining 6 are reduced in thickness. The thickened free end of the strap 17 is in contact with the side walls 16 of the groove 15 on both sides. A gap 19 remains between the straps 17 and the side walls 16 on the end of the strap 17 confronting the housing 4. It is convenient to make the annular part 5 merge arcuately into the side walls 16 of the flange 11.A gap 20 remains between the mutually confronting surfaces of the bracing rings 7 and the flange 11 of the seal lining 6, whilst here again the mutually confronting surfaces of the bracing rings 7 and the external surfaces of the walls 16 of the flange 1 are conveniently of arcuate configuration.

With this configuration the sealing lip 1 and the flange 11 simultaneously execute a pendulum and slight vertical movement during closing and opening of the flap 3.

The embodiment according to Figure 5 is analogous to the embodiment according to Figure 3. However, the annular part 5 of the seal lining 6 abuts on the one hand against the housing 4 and on the other hand against the gracing rings 7. The side walls 16 of the flange 11 are reduced in thickness. The transition from the annular parts 5 to the side walls 16 is arcuate on both sides. The bracing rings 7 abut with their mutually confronting ends against the side walls 16 of the flange 11 of the seal lining 6. In this embodiment, when the flap 3 is opened or closed, the seal lining 6 executes a bellows-like movement in the region of the flange 11.As illustrated in Figure 5 (right-hand side), it is possible, and advantageous in the case of the embodiments without straps 17 or 17, 21 to provide the bracing rings 7 on one or on both sides of the sealing lips 1 which encircling breaks 49 respectively interrupted by the journals 14 (not shown in Figure 5). The seal lining 6, more particularly the sealing lip 1 on the side opposite the action of pressure, can be braced against said breaks 49.

Figures 7 and 8 shows convenient embodiments of seals in the region of the journals for a seal lining made of substances such as polytetrafluoroethylene.

As may be seen from Figure 6, a groove 22 is arranged round the journals 14 on the side confronting the flap 3. The groove 22 is conveniently triangular in crosssection. One arm of the groove 22 terminates at the journals 14, so that a lip 45 remains between the groove 22 and the journals 14. The flap 3 exhibits, on the side, confronting the sealing lip 1, a recess 26 surrounding the journals 14. The recess 26 is narrower on the mutually confronting sides than the groove 22. A seal ring 23 is inserted into the recess 26 and projects out of the recess 26 with a part 24. The projecting part 24 is likewise of triangular conformation and the surface of the projecting part 24 confronting the journal 14 abuts against the surface of the lip 45 of the seal lining 6 remote from the journals 14.Between the surfaces, remote from the journals 14, of the projecting part 24 of the sealing ring 23 and the groove 22 there remains a gap into which fluid medium can penetrate in the open position of the flap 3. The projecting part 24 is therefore urged against the lip 45 and urges the latter towards the journals 14. It is also possible to provide the surfaces, remote from the journals 14, of the projecting part 24 additionally with an encircling re-entrant portion 28, so that the top tip of the projecting part 24 is of lip-shaped construction and is urged against the lip 45 of the seal lining 6 by the service pressure of the fluid medium. In order to further increase the yieldability of the lip 45 of the seal lining 6, it is possible to provide an additional groove 31 in the seal lining 6 around the journals 14 at an interval from the groove 22.The seal ring 23 may also exhibit in the region of the recess 26, more particularly in the base, a groove in which a seal 25, conveniently an O-ring, is arranged, which abuts against the base of the recess 26 and seals the groove 22 here against the journals. In the exemplary embodiment illustrated the seal lining 6 has on its side remote from the sealing lip 1 a bearing neck 35 enclosing the journals 14, with which a bearing bushing 32 abuts by one end. The bearing neck 35 may also be taken as far as bearing cover 46 and serve as bearing bushing. The bearing neck 35 is surrounded by a seal ring 33 which is urged by means of a further bushing 36 against the seal lining 6 and thus creates additional security for the fluid-tightness.On the outside of the housing 4 is arranged the bearing cover 46, which is sealed with respect to the housing 4 by means of a seal 47 and with respect to the journals 14 by means of a seal 48.

In the embodiment according to Figure 7 the surface, remote from the journals 14, of the sealing ring 23 has a re-entrants portion 30 which forms a lip 29 in abutment with that side of the recess 26 remote from the journals 14. The lip 29 is urged by the service pressure of fluid medium against that side of the recess 26 remote from the journal 14 and thus seals the groove 22 with respect to the journal 14. A spring, more particularly a spiral spring, 27 is arranged between the bottom face of the sealing ring 23 and the base of the recess 26. In this embodiment the seal lining has no bearing neck. The seal ring 33 is placed between housing 4 and journals 14 and is urged against the seal lining 6 by the bearing bushing 32.It is possible here to provide in the seal lining 6, on the side confronting the seal ring 33, a groove in which a further seal 34 more particularly an O-ring, is arranged.

In the embodiment according to Figure 8, which is analogous to the embodiments shown in Figures 3 and 5, the annular part 5 of the seal lining 6 is cylindrically conformed at least with respect to both ends.

The seal lining 6 can be inserted into the housing without difficulty. The sealing to the side is effected by means of a seal ring 42, more particularly an O-ring.

In the embodiments according to Figures 9, 10 and 11, the mutually confronting surfaces of seal lining 6 and flap 3 have recesses encircling the journals 14 in the region of the journals 14.

In the embodiment according to Figure 9 the recesses are of rectangular conformation. Sealing rings 50 and 51 made of polytetrafluoroethylene, between which a sealing ring 52 made of an elastomer is inserted, are inserted into the recesses respectively on the side confronting the journals 14 (or a bearing shaft ) and on the side remote from the journal 14 (or bearing shaft). The sealing ring 52 made of an elastomer urges the sealing ring 50 made of polytetrafluoroethylene or a similar substance towards the journals 14 (or bearing shaft), and the sealing ring 51 made of similar substance against the side, remote from the journals 14 (or bearing shaft), of the recess in the flap 3 and in the seal lining 6.By this means again, it is possible for a relatively simple conformation of the sealing means 50, 51 and 52, to seal the journals 14 (or bearing shaft) here in such a way that fluid medium cannot penetrate through between flap 3 and sealing lip 1 to the journals 14 (or bearing shaft) and to the housing 4. The sealing ring 50 made of polytetrafluoroethylene or the like, which abuts against the journal 14 (or bearing shaft), furthermore reduces the friction between the sealing means 50, 51, 52 and the journal 14 (or bearingshaft).

In the embodiment according to Figure 10 the recesses round the journals 14 (or bearing shaft) are made in the mutually confronting surfaces of flap 3 and seal lining 6 in such a way that they are conjointly trapezoidal. A sealing ring 53 made of an elastomer or the like, which is likewise of trapezoidal conformation, is arranged in the said recesses. Between the sealing ring 53 and the seal lining 6 or the flap 3, a coffin lid-shaped ring 54 made of polytetrafluoroethylene or another substance which behaves similarly is provided.

The sealing ring 53 made of an elastomer or the like is here squeezed and urges the coffin lid-shaped ring 54 made of polytetrafluoroethylene or of a similar substance towards the flap 3 and the seal lining 6. The base of the conjointly trapezoidal recesses abuts against the journals 14 (or bearing shaft).

In the embodiment according to Figure 11 the recesses in the mutually confronting surfaces of seal lining 6 and flap 3 are again rectangular on the side confronting the journal 14 (or bearing shaft). Into this overall rectangular recess there is inserted a sealing ring 55 made of an elastomer or the like, whilst between the sealing ring 55 and the flap 3 or the seal lining 6 a channel-shaped ring 56 of polytetrafluoroethylene or of a similar substance is placed.

Here again the seal ring 55 is squeezed and urges the ring 56 made of polytetrafluoroethylene or the like towards the seal lining 6 or the flap 3, so that fluid medium cannot penetrate between flap 3 and the sealing lip 1 to reach the journals 14 (or bearing shaft) and further the housing 4.

If the bracing rings 7 consist of metal, then it is advantageous to make the housing 4 project laterally with reference to the bracing ring 7, more particularly its encircling flange 39 (shown for instance in Figure 8), and to arrange between bracing ring 7 and flange 39 on the one hand and the pipe or the like to be connected on the other hand a seal element which is limited outwards by the inner edge of the projecting part of the housing 4. In this way a good seal is obtained between valve and pipe or the like to be connected even with metallic bracing rings 7 and high pressure.

In the embodiment according to Figure 12 a ring 101 is inserted into the seal lining 6. Thet ring 101 is interrupted by bearing bushings 32 or the journals 14.

Bearing bushing 32 and journal 14 are shown for instance in Figure 6. With appropriate production it is naturally possible to provide the ring 101 with corresponding bores for the journals 14 or bearing bushings 32 and to pass the ring 101 round the bearing bushings 32 or the journals 14.

The ring 101 carries the encircling strap 102 which engages into the groove 15 in the seal lining 6 and, correspondinly to the ring 101, terminates in front of the bearing bushings 32 or the journals 14 or is carried round them. If the ring 101 is carried round the journals 14 or the bearing bushing 32, it should be divided parallel to the axis, preferably in the region of the bores for the bearing bushings 32 or the journals 14. For assembly it is advantageous to insert the ring 101 into the seal lining 6 and then to push both parts conjointly into the housing 4. The lateral flanges 37 of the seal lining 6 in this embodiment extend only to the outer peripheral surface of the ring 101.

The ring 101 is then thinner than the housing 4 by the thickness of the two flanges 37. In order to obtain a larger sealing surface between the housing 4 and the service pipes etc., to be connected, it is possible to provide the housing 4 laterally on the inside with a recess into which an additional sealing ring 137 is inserted. It is then convenient to provide bracing means 103 for the gap 8 between the annular parts 5 of the seal lining 6 and for the ring 101 at the mutually remote ends, as illustrated on the left-hand side in Figure 12.Instead of the additional sealing ring 137 it is possible to provide the seal lining 6 with a correspondingly long flanges 37, of which at least one lies in a plane with the outer surface of the annular parts 5 during the production of the seal lining 6 and is then bent upwards-e.g., after previous warming-after insertion into the housing.

The conformation can then be made such that the flanges 37 seal directly with respect to the housing. But it is also possible to provide additional sealing means between the flanges 37, the seal lining 6, the housing 4 and the bracing rings 7, as illustrated and described in the previous Figures. The gaps 8 and 18 between the annular parts 5 of the seal lining 6 and the ring 101 and between the encircling strap 102 and the base of the groove 15 in the seal lining 6 should exhibit equal heights. The gaps 8 and 18 should also be closed when the flap 3 is closed. Thus relatively great flexibility of the seal lining 6 is obtained without the possibility during service for the service pressure of fluid medium to spread the annular parts 5 of the seal lining 6 radially in the closed position of the flap 3.

In the embodiment according to Figure 13, the housing 4 contains in the regions of the flange 11 of the seal lining 6 a groove 104 into which a sealing ring 105 is interted which abuts against the base of the groove 104 and against the seal lining 6. Here again it is possible to extend the groove 104 and the sealing ring 103 round the journals 14 or the bearing bushings 32.

The ring 105 is then conveniently an elastomer ring. The cross-section of this ring is unimportant. The sealing ring 105 creates the appropriate pre-tension for the fluidtightness immediately after closure of the flap. The requisite fluid-tightness under service presure is again obtained because the service pressure can act upon that side of the sealing lip 1 remote from the flap 3. It will be realised that, with increasing service pressure of fluid medium, the contact pressure of the sealing lip 1 against the peripheral surface of the flap 3 also increases. In this case it is necessary to arrange the sealing ring 105 so that it cannot be displaced by the service pressure of the fluid medium.The gap 8 between the mutually confronting surfaces of the seal lining 6 and of the housing 4 is again dimensioned so that, the flap 3 being closed, the gap 8 is closed in the region of the flap 3. It is then practically irrelevant whether, the flap 3 being open, the seal lining 6 is braced through the flanges 37 against the housing edge 4b or against a separate bracing means 102 which is arranged on the mutually confronting ends of the gap 8 as shown on the left-hand side of Figure 13. The housing 4 can be of twopart or also integral construction. If the housing 4 is of integral construction, then it is advantageous during the production of the seal lining to produce at least one of the flanges 37 in a plane with the external surface of the annular parts 5 of the seal lining 6, and to bend it upwards, e.g.

after previous prewarming, after insertion into the housing. It is obviously possible to omit the groove 104 in the housing 4 and to insert the sealing ring 105 into the groove 15 in the seal lining 6. Encircling straps 17, 21 and 102 are then superfluous.

If desired, the grooves 15 or 104 in the sealing ring 105, and in the encircling straps 17, 21 and 102 may also be omitted. In this case however it is convenient to make the lip 1 on the free end of the flange 11 of the seal lining 6 longer in order to ensure that the service pressure of the fluid medium can act correctly upon that side of the lip 1 remote from the flap 3.

In all embodiments, the bracing rings 7 should be constructed so that they perform the necessary bracing of the seal lining 6 and/or the lip 1.

In this context it is irrelevant whether or not the bracing rings exhibit additional flanges 39.

It is obvious that the individual features of the exemplary embodiments illustrated can be mutually combined to a very great extent to suitable individual requirements.

Figures 14 and 15 illustrated further convenient, and more particularly highly economical, embodiments of sealing means in the region of the journals for a seal lining made of a substantially inelastic plastics material such as polytetrafluoroethylene. In the case of the known sealing means in the region of the journals when using a seal lining made of a substantially inelastic plastics material such as polytetrafluoroethylene, but also in the case of the embodiments illustrated in Figures 6, 7 and 9 to 11, the sealing to the side upon which the medium acts upon the shut-off flap valve, is provided with a protection of a corresponding plastics material, e.g., polytetrafluoroethylene, which is braced on the side remote from the medium by a sealing means made of another material, e.g., an elastomer.It is thus intended to achieve that the sealing means is protected so far as possible from any corrosive influence by fluid medium. However, when using an appropriate sealing means, e.g., a suitable elastomer, it is also possible to insert such a plastics material directly as sealing means between sealing lining and flap. A better seal is obtained by this means, simply because e.g., an elastomer swells readily when it comes into contact with the medium and thereby creates a higher contact pressure and hence greater fluid-tightness.

The fluid-tightness is also improved by the better adhesion of the elastomer to the seal lining.

In the embodiment according to Figure 14 the flap 3 contains on the side confronting the seal lining 6 a groove 106 into which an O-ring 107 is inserted which seals the journals 14 or the bearing bushings 32 from fluid medium in the region of the journals 14 or of the bearing bushings 32.

In this case the groove 106 is arranged in the flap 3 round the journals 14 or the bearing bushing 32.

In the embodiment according to Figure 15, the flap 3 contains round the journal 14 on the side confronting the seal lining 6 a recess 108 into which a sealing sleeve 109 is inserted. The sealing sleeve 109 is conveniently U-shaped in cross-section, whilst the open side confronts fluid medium, i.e., the side from which the fluid medium acts upon the shut-off flap valve. With such an embodiment, if the fluid medium actually penetrates between seal lining 6 and flap 3, it presses into the U-shaped sealing sleeve and presses its arms against the flap 3 and against the seal lining 6. It is obviously possible to insert an O-ring 107 (cf. Figure 14) into the recess 108, and conversely a sealing sleeve 109 into the groove 106 (cf. Figure 14). It is also possible to arrange the groove 106 or the recess 108 in the seal lining 6.

It is naturally possible, more particularly for low service pressures of fluid medium, to produce housing 4 and seal lining 6 integrally from an inelastic, or only slightly elastic, plastics material such as polytetrafluoroethylene.

The flap may consist of metal, e.g., stain less steel, or, alternatively, of plasticsenveloped solid cores, e.g. plasticsenveloped metal cores.

WHAT I CLAIM IS: - 1. A shut-off flap valve for service pipes and the like having a flap mounted pivotably in a valve housing which flap, in the closed position of the valve, abuts against the inside surface of an inwardly concavely curved sealing lip, having oppositelydirected free edges, on a radially inwardly oriented encircling flange of a seal lining made of a plastics material arranged on the housing, and having gracing rings arranged on both sides of the flange, between which bracing rings and housing the seal lining is placed, wherein in the open position of the valve the internal diameter of the inside surface of the curved sealing lip perpendicular to the axis of the shut-off flap valve and parallel to the pivot axis of the flap is slightly less than the diameter of the flap perpendicular to the axis of the shut-off flap valve and parallel to the pivot axis of the flap, and by the provision, in the open position of the valve, of (a) a gap between the housing, or a member adjacent to the housing, and the seal lining and (b) a gap between the sealing lip and each bracing ring, the sealing lip is adapted to yield with respect to the closing movement of the flap to accommodate the flap to permit the flap to abut against the inside surface of the sealing lip to close the valve.

2. Shut-off flap valve according to Claim 1, wherein the seal lining is made of a substantially inelastic plastics material.

3. Shut-off flap valve according to Claim 1 or Claim 2, wherein the seal lining is made of a polymer derived from the fluorohydro carbon.

4. Shut-off flap valve according to Claim 3, wherein the polymer is polytetrafluoro ethylene.

5. Shut-off flap valve according to any preceding claim, wherein the flange of the seal lining has an annular groove open towards the housing, the annular groove being interrupted by means pivotably mounting the flap.

6. Shut-off flap valve according to any preceding claim, wherein in the open position of the flap a gap remains between the housing and an annular part of the seal lining and a gap between each bracing ring and the surface, remote from the flap, of the sealing lip.

7. Shut-off flap valve according to any one of Claims 1 to 5, wherein in the open position of the flap an annular part of the seal lining abuts against the housing and bracing rings, a gap which remains between each bracing ring and the surface confront

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. inelastic plastics material such as polytetrafluoroethylene, but also in the case of the embodiments illustrated in Figures 6, 7 and 9 to 11, the sealing to the side upon which the medium acts upon the shut-off flap valve, is provided with a protection of a corresponding plastics material, e.g., polytetrafluoroethylene, which is braced on the side remote from the medium by a sealing means made of another material, e.g., an elastomer. It is thus intended to achieve that the sealing means is protected so far as possible from any corrosive influence by fluid medium. However, when using an appropriate sealing means, e.g., a suitable elastomer, it is also possible to insert such a plastics material directly as sealing means between sealing lining and flap.A better seal is obtained by this means, simply because e.g., an elastomer swells readily when it comes into contact with the medium and thereby creates a higher contact pressure and hence greater fluid-tightness. The fluid-tightness is also improved by the better adhesion of the elastomer to the seal lining. In the embodiment according to Figure 14 the flap 3 contains on the side confronting the seal lining 6 a groove 106 into which an O-ring 107 is inserted which seals the journals 14 or the bearing bushings 32 from fluid medium in the region of the journals 14 or of the bearing bushings 32. In this case the groove 106 is arranged in the flap 3 round the journals 14 or the bearing bushing 32. In the embodiment according to Figure 15, the flap 3 contains round the journal 14 on the side confronting the seal lining 6 a recess 108 into which a sealing sleeve 109 is inserted. The sealing sleeve 109 is conveniently U-shaped in cross-section, whilst the open side confronts fluid medium, i.e., the side from which the fluid medium acts upon the shut-off flap valve. With such an embodiment, if the fluid medium actually penetrates between seal lining 6 and flap 3, it presses into the U-shaped sealing sleeve and presses its arms against the flap 3 and against the seal lining 6. It is obviously possible to insert an O-ring 107 (cf. Figure 14) into the recess 108, and conversely a sealing sleeve 109 into the groove 106 (cf. Figure 14). It is also possible to arrange the groove 106 or the recess 108 in the seal lining 6. It is naturally possible, more particularly for low service pressures of fluid medium, to produce housing 4 and seal lining 6 integrally from an inelastic, or only slightly elastic, plastics material such as polytetrafluoroethylene. The flap may consist of metal, e.g., stain less steel, or, alternatively, of plasticsenveloped solid cores, e.g. plasticsenveloped metal cores. WHAT I CLAIM IS: -

1. A shut-off flap valve for service pipes and the like having a flap mounted pivotably in a valve housing which flap, in the closed position of the valve, abuts against the inside surface of an inwardly concavely curved sealing lip, having oppositelydirected free edges, on a radially inwardly oriented encircling flange of a seal lining made of a plastics material arranged on the housing, and having gracing rings arranged on both sides of the flange, between which bracing rings and housing the seal lining is placed, wherein in the open position of the valve the internal diameter of the inside surface of the curved sealing lip perpendicular to the axis of the shut-off flap valve and parallel to the pivot axis of the flap is slightly less than the diameter of the flap perpendicular to the axis of the shut-off flap valve and parallel to the pivot axis of the flap, and by the provision, in the open position of the valve, of (a) a gap between the housing, or a member adjacent to the housing, and the seal lining and (b) a gap between the sealing lip and each bracing ring, the sealing lip is adapted to yield with respect to the closing movement of the flap to accommodate the flap to permit the flap to abut against the inside surface of the sealing lip to close the valve.

ing them of the sealing lip and two side walls of the flange are reduced in thickness.

8. A shut-off valve according to any preceding claim, wherein mutually confronting surfaces of the bracing rings have a groove in which a seal ring abuts against the flange of the seal lining.

9. Shut-off flap valve according to Claim 8, wherein the said seal ring is an O-ring.

10. Shut-off-flap valve according to any one of Claims 1 to 7, wherein a surface of the bracing rings confronting an annular part of the seal lining has at a short interval from the flange of the seal lining a groove in which a yieldable seal ring is arranged.

11. Shut-off flap valve according to Claim 10, wherein the said yieldable seal ring is an O-ring.

12. Shut-off flap valve according to any one of Claims 1 to 7, having bracing rings made of a substantially inelastic plastics material, wherein the sides of the bracing rings confronting the flange of the seal lining are constructed as sealing lips abuting against the flange and oriented towards the sealing lip of the seal lining.

13. Shut-off flap valve according to Claim 12 wherein the plastics material of the bracing ring sealing lips is as specified in Claim 3 or Claim 4.

14. Shut-off flap valve according to Claim 5 or any claim appendant thereto, wherein the housing is provided with an annular strap projecting into the annular groove, the annular strap being interrupted by the means pivotally mounting the flap, whilst a gap remains between the free end of the strap and the base of the groove in the open position of the flap.

15. Shut-off flap valve according to Claims 5, 6, 7 and 14, wherein the strap is tear-shaped, the free end of the strap abuts against the side walls of the groove on both sides and in the open position of the flap there is a gap which remains between the end of the strap confronting the housing and the seal lining and a gap remains between each bracing rings and at waisted portion of the flange.

16. Shut-off flap valve according to Claim 14 and/or Claim 15, wherein the housing has internally an annular groove interrupted by the means pivotally mounting the flap and into which semicircular segments are inserted as a strap.

17. Shut-off flap valve according to any preceding claim, wherein means pivotably mounting the flap comprises a pair of journals and around each journal on the side thereof confronting the flap the said curved sealing lip has a groove there, and the flap has around each journal a recess into which a seal ring projecting out of the recess is inserted, the surface of which seal ring confronting the journal abuts against a projecting part on the wall of the said groove confronting the journal.

18. Shut-off flap valve according to Claim 17, wherein the said seal ring has on its underside a groove into which another seal ring, abutting against the base of the said recess is inserted.

19. Shut-off flap valve according to Claim 18, wherein the said another seal ring is an O-ring.

20. Shut-off flap valve according to Claim 17, wherein a spring is arranged between the underside of the said seal ring and the base of the said recess.

21. Shut-off flap valve according to Claim 20, wherein the spring is a spiral spring.

22. Shut-off flap valve according to any one of Claims 17 to 21, wherein a gap remains between the surfaces of the groove (first mentioned in Claim 17) confronting each journal and of that part of the said seal ring projecting out of the said recess.

23. Shut-off flap valve according to any one of Claims 17 to 22, wherein the groove (first mentioned in Claim 17) and the said projecting part of the said seal ring are of triangular configuration.

24. Shut-off flap valve according to any one of Claims 17 to 23, wherein the surface, remote from each journal, of that part of the said seal ring projecting out of the said recess has a re-entrant angle portion located at right angles to the axis of the journals.

25. Shut-off flap valve according to any one of Claims 17 to 23, wherein the surof the said seal ring remote from each journal has a re-entrant angle portion forming a lip in abutment with that side of the said recess remote from the journals.

26. Shut-off flap valve according to any one of Claims 17 to 25, wherein the said seal ring consists of a substantially inelastic plastics material.

27. Shut-off flap valve according to Claim 24, wherein the plastics material of the said seal ring is as specified in Claim 3 or Claim 4.

28. Shut-off flap valve according to any preceding claim, wherein means pivotably mounting the flap comprises a pair of journals and the seal lining has an indentation round the journals between the said curved sealing lip and housing.

29. Shut-off flap valve according to any preceding claim, wherein a seal ring urging the seal lining towards -the flap is arranged between seal lining and a bearing bushing.

30. Shut-off flap valve according to Claim 29, wherein an O-ring is arranged between the said seal ring and seal lining.

31. Shut-off flap valve according to any one of Claims 1 to 29, wherein means pivot ably mounting the flap comprises a pair of journals and the seal lining has a bearing neck placed around the journals, against which bearing bushings abuts with their ends confronting the flap.

32. Shut-off flap valve according to Claim 31, wherein the seal ring urging the seal lining towards the flap is arranged round the bearing neck and is urged against the seal lining by further bushings.

33. Shut-off flap valve according to any preceding claim, wherein the seal lining has outwardly oriented flanges encircling on both sides of the housing, which flanges are placed in corresponding recesses in the housing.

34. Shut-off flap valve according to Claim 33, wherein the seal lining has a recess in the edge between an annular part of the seal lining and said outwardly oriented flange.

35. Shut-off flap valve according to Claim 34, wherein the said recess is an external recess.

36. Shut-off flap valve according to Claim 34 or Claim 35, wherein the said recess is a throat-shaped recess.

37. Shut-off flap valve according to any one of Claims 1 to 32, wherein the bracing rings have outwardly oriented flanges or attachments encircling on both sides of the housing which engage in corresponding recesses in the housing.

38. Shut-off flap valve according to any one of Claims 1 to 32 and Claim 37, wherein the outer ends of annular parts of the seal lining are angled outwards and the edges of the housing and of the seal lining are correspondingly bevelled and abut against an angled part.

39. Shut-off flap valve according to any preceding claim, wherein the bracing rings, have on one or both sides of the said curved sealing lip an encircling beak interrupted by means pivotably mounting the flap.

40. Shut-off flap valve according to any preceding claim, wherein a surface of the bracing rings confronting an annular part of the seal lining has at the ends of the annular part an encircling groove in which a seal is arranged.

41. Shut-off flap valve according to Claim 40, wherein the seal first mentioned in Claim 40 is an O-ring.

42. Shut-off flap valve according to any preceding claim, wherein edges, confronting the bracing rings, at the end of an annular part of the seal lining are bevelled and the bracing rings have an attachment abutting against the bevel on the side confronting the annular part and the end remote from the flange of the seal lining.

43. Shut-off flap valve according to Claim 31, wherein the bearing neck extends to a bearing cover and constitutes a bearing bushing.

44. Shut-off flap valve according to Claim 33 or Claim 37, wherein the encircling flanges or the attachment project with respect to the housing, a gap remains between the said flanges or attachments and the surfaces of the housing confronting them, the seal rings which are arranged in grooves in the surface of the housing confronting the said flanges or attachments are arranged in the said gap.

45. Shut-off flap valve according to Claim 44, wherein the seal ring first mentioned in Claim 44 are elastomeric rings.

46. Shut-off flap valve according to Claim 38, wherein the inner peripheral surface of the said angled part and the outer peripheral surface of the bracing rings abutting therewith are cylindrically conformed.

47. Shut-off flap valve according to any one of Claims 1 to 37, 39, 40, 43 and 44.

wherein the ends of the annular part of the seal lining and the surfaces of the bracing rings and of the housing abutting therewith are cylindrically conformed.

48. Shut-off flap valve according to any one of Claims 1 to 16 and any one of Claims 28 to 47, wherein means pivotably mounting the flap comprises a pair of journals and the seal lining and flap have around the journals on the mutually confronting sides, similarly conformed recesses open on the mutually confronting sides, a seal ring is inserted into the said recess on the side confronting the journals, and a seal ring made of a substantially inelastic plastics material is arranged in the side remote from the journals.

49. Shut-off flap valve according to Claim 48, wherein the seal ring first mentioned in Claim 48 is an elastomeric ring.

50. Shut-off flap valve, according to Claim 48 or Claim 49, wherein the material of the seal ring mentioned secondly in Claim 48 is as specified in Claim 3 or Claim 4.

51. Shut-off flap valve according to any one of Claims 48 to 50, wherein a ring made of a substantially inelastic plastics material is arranged between the journals and a seal ring as first mentioned in Claim 48.

52. Shut-off flap valve according to Claim 51, wherein the material of the ring first mentioned in Claim 51 is as specified in Claim 3 or Claim 4.

53. Shut-off flap valve according to any one of Claims 48 to 51, wherein the seal ring mentioned secondly in Claim 48 is of channel-shaped conformation open towards the journals and abuts against the journals with its free ends.

54. Shut-off flap valve according to any one of Claims 48 to 53, wherein the re cesses in the seal lining and in the flap conjointly exhibit a rectangular configuration.

55. Shut-off flap valve according to any one of Claims 48 to 53, wherein recesses in the seal lining and in the flap conjointly exhibit a trapezoidal conformation with the base located on the journals.

56. Shut-off flap valve according to any one of Claims 1 to 10, wherein the bracing rings consist of a substantially inelastic plastics material.

57. Shut-off flap valve according to Claim 56, wherein the said plastics material is as specified in Claim 3 or Claim 4.

58. Shut-off flap valve according to any of Claims 1 to 55, wherein the bracing rings are made of metal, and wherein the housing projects lateraly with respect to the bracing rings and between each bracing ring and the flange on the one hand and the pipe to be connected on the other hand a seal is arranged which is limited outwardly by the inner edge of a projecting part of the housing.

59. Shutoff flap valve according to Claim 58, wherein the housing projects laterally with respect to an encircling flange of the bracing ring.

60. Shut-off flap valve according to any preceding claim, wherein there is provided a said member adjacent to the housing, which member is a ring arranged in the seal lining on the side confronting the housing.

61. Shut-off flap valve according to Claim 60, wherein the ring first mentioned in Claim 60 has on the side remote from the housing an encircling strap which engages into the groove (first mentioned in Claim 5) in the seal lining.

62. Shut-off flap valve according to Claims 33 and 61, wherein the outwardly oriented flanges of the seal lining extend to the outer peripheral surface of the ring first mentioned in Claim 60, and the said ring is shorter than the housing by the thickness of the two flanges.

63. Shut-off flap valve according to Claim 62, wherein the housing has internally on both sides recesses into which seal rings are inserted.

64. Shutoff flap valve according to Claim 61 or Claim 62, wherein a gap remains between the ring first mentioned in Claim 60 and annular parts of the seal lining and between the encircling strap and the base of the said groove in the seal lining.

65. Shut-off flap valve according to any one of Claims 60 to 63, wherein the ring first mentioned in Claim 60 is divided into two halves parallel to its axis.

66. Shut-off flap valve according to Claim 65, wherein the means pivotably mounting the flap comprises a pair of journals and the said ring is divided in the region of the bores for the journals.

67. Shut-off flap valve according to any one of Claims 60 to 63, wherein the ring first mentioned in Claim 60 is interrupted by means pivotably mounting the flap.

68. Shut-off flap valve according to any preceding claim, wherein means pivotably mounting the flap comprises a pair of journals and an encircling strap is provided around the journals.

69. Shut-off flap valve according to any one of Claims 60 to 68, wherein a bracing means is arranged in a gap at mutually remote ends.

70. Shut-off flap valve according to any preceding claim, wherein gaps between the housing or ring as first mentioned in Claim 60 and seal lining, and between the base of a groove as defined in Claim 5 and an encircling strand are of equal height.

71. Shut-off flap valve according to Claim 70, wherein the housing or ring as first mentioned in Claim 60 and seal lining, and the base of the groove as defined in Claim 5 and encircling strap abut one another when the flap is closed.

72. Shut-off flap valve according to any one of Claims 1 to 12, 17 to 58, 62, 63 and 69 to 71, wherein in an inner peripheral surface in the housing there is arranged a groove into which a yieldable ring abutting against the seal lining is inserted.

73. Shut-off flap valve according to Claim 72, wherein the groove specified in Claim 72 is arranged in the housing in the region of an encircling flange of the seal lining, into which the said yieldable ring specified in Claim 72 abutting against the seal lining is inserted.

74. Shut-off flap valve according to Claim 72 and/or Claim 73, wherein the groove specified in Claim 72 and ring specified in Claim 72 are interrupted by means pivotably mounting the flap.

75. Shut-off flap valve according to Claim 72 and/or Claim 73, wherein the groove and ring specified in Claim 74 extend around means pivotaly mounting the flap.

76. Shut-off flap valve according to any one of Claims 1 to 12, 17 to 58, 62, 63, 69 to 71, 74 and 75, wherein the ring as specified in Claim 72 is arranged in a groove as specified in Claim 5 in the seal lining.

77. Shut-off flap valve according to any preceding claim, wherein means pivotably mounting the flap comprises a pair of journals and the flap has around the journals on the side confronting the seal lining a groove into which an O-ring is inserted which abuts against the seal lining.

78. Shut-off flap valve according to any one of Claims 1 to 76, wherein means pivotably mounting the flap comprises a pair pair of journals and the flap on the side confronting the three seal lining on the journal and around the latter a recess into which a sealing sleeve which abuts against the seal lining is inserted.

79. Shut-off flap valve according to Claim 78, wherein the sealing sleeve is of U-shaped conformation and is open on the side remote from the journal.

80. Shut-off flap valve according to any preceding claim, wherein the width of the seal lining in both sides thereof is equal to or smaller than the width of the housing.

81. A shut-off flap valve substantially as herein described and with reference to any one of Figures 1 to 11 of the accompanying drawings.

82. A shut-off flap valve substantially as herein described and with reference to any one of Figures 12 to 15 of the accompanying drawings.