Non-return valve with a moving valve body and method of blocking the reverse liquid flow by means of the valve The invention relates to a non-return valve with a moving valve body, whose casing has a through-channel (conduit) with an outlet and an inlet with a ring seat or a nest, intended for the moving valve body to be settled in closed position, and has additionally a deflected area of width greater than the moving valve body, intended for the valve body to enter when in the valve open position, wherein at the inlet, at place where the deflected area lower part merges with the through-channel, the casing has extended cross- section of the flow area connected directly to the through-channel and is provided inside with a protrusion, deflected in relation to the through-channel, which constitutes the guide bar for the moving valve body, or is provided with a place for pendulous catch of the moving valve body, and in the corner, at place where the deflected area upper part merges directly with the through-channel at the outlet side the decreased pressure area exists, enclosed by internal surface of the casing corner wall, which connects the deflected area upper part with the through-channel.

The invention also relates to a method of blocking reverse flow of the liquid by means of the moving valve body being settled in closed position in the ring seat or in the nest, wherein the moving valve body moves in open position into the deflected area under the influence of reduced pressure of the liquid flowing through the flow area of extended cross-section in the corner connecting directly the deflected area upper part with the through-channel from the outlet side.

In known from Polish patent description no. PL 174 939 non- return valve with a moving valve body in a form of a ball inside the valve casing, in front of the corner connecting the through-channel with the upper part of the deflected area, the double-sided hollow is located symmetrically in relation to the valve symmetry axis, created by external bulge of the casing wall.

Operational examinations of such solution of the valve have proved, that both the liquid flow energy loss and the valve vibrations are considerably reduced in comparison with known valves of similar kind.

However, the valve vibrations were not eliminated, especially with high flow of the liquid, but only reduced. The valve vibrations indicate disturbed flow of the liquid, which causes additional energy loss of the liquid flow through the valve.

The main cause of the vibrations is instability of the moving valve body in the open position because in most known non-return valve designs flow of the liquid occurs both under and above the moving valve body. Little perturbations in the liquid stream flowing can cause sudden change of the moving valve body position. It also applies to the flap valves, though the flap instability is lower in this case. Large and flat surface of the flap better damps disturbances appearing in the liquid flowing round the flap, in which the flap nearly flows because of its pendulous attachment. In the flap valves the greater problem exists of quick closing of the flap in case of the reverse flow because large and not enough streamlined surface of the flap damps its quick reversing to the closed position and settling in the nest. Still greater problem exists due to unforseeability of the move direction of the moving valve body, especially of the flap, when the nest is positioned horizontally and the flow direction is from bottom to top. In such a case, when at the moment of the flap deflecting toward the nest the liquid flow suddenly disappears, the flap also must change its move direction, what can cause uncontrolled hydraulic stroke. Such a hydraulic stroke can be much stronger than it will be in case of the flap being still in such a critical moment. The same also applies to the ball non-return valve, though in a less degree.

There are also known non-return valves, especially intended for assembling between flanges, in which the flap is deflected by a reduced angle only, e. g. 60 degrees, and is blocked in this position. It prevents strong and unforseeable hydraulic strokes during reverse flow of the liquid but causes considerable energy loss of the liquid or gas pressure and its application is limited in case of liquids and gases being polluted with solid particles, which can block the gap between the flap edge and the valve casing internal wall.

In case of the non-return valves, wherein the moving valve body moves from the closed position to the open position (and inversely) along the inlet and outlet axis, the problem exists of high loss of energy of liquid flow through the valve. The loss is caused

particularly by strong distortion of the stream around the moving valve body.

The methods being known until now of reverse blocking of liquid flow by means of moving valve body have not ensured proper holding stability of the moving valve body in proper place and at the same time have not ensured low flow resistance and low suppleness of the moving valve body to blocking by solid particles encountered e. g. in waste water. Also the method until now has not been developed of effective and forseeable closing of the non-return valve during short time, which at the same time is dispensed of necessity of substantial reduction of the liquid flow cross-section of the valve and necessity of providing the valve with elements intended for reducing effects of the hydraulic strokes or eliminating the strokes.

As a result of deep-rooted analyses of the state-of-the-art and the research carried out on further reduction of the liquid flow resistance in non-return valves and on elimination of the moving valve body position changing under the action of disturbances of the liquid flow in the pipeline having mounted the valve, the new design of the valve was developed according to the invention.

As a result of the same research the method was developed, which enables the moving valve body being held up in the constant fully open position and closed with forseeable effects under the sudden flow disappearing.

The valve according to the invention is characterised in that the mowing valve body in the open position separates, hermetically in principle, the reduced pressure area from the upper part of the deflected area. In one of possible versions the moving valve body is a ball (spherical body) and at the place where the deflected area upper part merges with the reduced pressure area the supporting seat is located, facing toward the deflected area and to the best advantage made in form of incomplete ring or of two incomplete halves of ring.

The supporting seat can be formed at the deflected area upper edge intersection with the reduced pressure area and/or at internal side of the casing corner wall, which connects the deflected area upper part with the through-channel.

In order to avoid the blocking of the valve according to the invention by solid particles contained in the flowing liquid,

especially in waste water, the passage area width of the supporting seat should be approximately the same as the through-channel width.

The supporting seat to the best advantage merges fluently with the protrusion creating a guide bar, and is made in the valve casing and/or in the cover.

In the valve version, wherein the deflected area is located at the inlet-outlet axis, the external surface of the ball in the fully open position divides the through-channel into two symmetrical parts.

In a possible different version the moving valve body is made in a form of the flap.

In one variant of this version the flap has on reverse side the sealing border made in a shape of horseshoe.

This border in the fully open position separates the reduced pressure area from the deflected area upper part when is settled in the opposite corner wall of the casing.

In different variant of this realisation the casing corner wall has the settling border in the shape of horseshoe, attached to the wall and intended for the flap reverse side to be settled in the fully open position. In such a way the reduced pressure area is separated from the deflected area upper part.

The sealing border or the settling border or both these borders create such a distance between the flap reverse side and the opposite casing corner wall, which ensures at least the flap tip, where the borders are opened, to be located in the field of the liquid flow through the conduit (through-channel) or to deflect the flow.

The method according to the invention consists in that the moving valve body is maintained in the fully open position by trap, tight in principle, accomplished with the valve body, of the passage between the deflected area upper part and the reduced pressure area.

This trap is maintained by the pressure difference existing between the points in front of the moving valve body and behind it at the adequate rate of liquid flow. The reverse liquid flow is blocked by additional usage of the hydraulic hammer energy of the impact of the part of reverse liquid flow towards the closed, in principle in a tight manner, reduced pressure area.

The pressure difference, existing between points in front of the moving valve body and behind it, is obtained by means of the through-channel passage contraction, made at the place where the channel is blanked off to the maximum degree by the moving valve body surface in front of the outlet, as compared to the passage cross- section at the outlet, or is obtained by deflecting the liquid flowing in the through-channel at the moving valve body edge.

The basic advantage of the valve according to the invention is that it ensures stability of the moving valve body position in the fully open position with inconsiderable disturbances of the liquid stream flowing through the valve and at the same time with low local loss of pressure. The valve design also ensures its proper operation with e. g. raw waste water flow through the valve, because the rapid closing of the water flow from the deflected area upper part to the reduced pressure area by the moving valve body, in the fully open position, prevents the moving valve body against blocking by the solid particles contained in the waste water.

The main advantage of the method according to the invention is that the local pressure loss is used to maintain the moving valve body in the fully opened position, and also to close the reduced pressure area being from the deflected area upper part.

The example of the object of the invention is presented in figures, where fig. 1-6 presents the longitudinal sectional view of the ball non-return valve casing; fig. 7-enlarged perpendicular projection A, corresponding with fig. 1-5, of fragment of the casing of the ball non-return valve with the supporting seat; fig. 8- transversal cross-section B-B, according to fig. 6, of the non return valve casing; fig. 9-12-longitudinal cross-section of the casing of the linear version and angular 90° version of the flap non-return valve; fig. 13-longitudinal cross-section of the linear version of the flap non-return valve; fig. 14-enlarged perpendicular projection C according to fig. 9 of the casing fragment of the non-return valve with the sealing border; fig. 15-enlarged perpendicular projection D according to fig. 10-13 of the casing fragment of the non-return valve with the supporting border.

The non-return valve shown in fig. 1-6 with the moving valve body made in the form of a ball (spherical body) 1 has the casing with the through-channel 2, having inlet with the ring seat 3, where

the ball 1 is settled in closed position. The casing has also the deflected area 4 of width greater than the ball 1 diameter, to which the ball 1 enters in the valve open position. Near the inlet, at the place of the lower part of deflected area 4 connection with the through-channel 2, the casing has extended cross-section of the flow area connected directly with the through-channel 2 and is provided inside with the protrusion 5 deflected in relation to the through- channel 2, performing the role of the guide bar for the ball 1. At the corner 6, connecting directly the upper part of the deflected area 4 with the through-channel 2, from its outlet side, the reduced pressure area 7 exists, bordered with internal surface of the casing corner wall 8, which connects the deflected area 4 upper part with the through- channel 2. The ball 1 in the fully open position separates in principally hermetic manner the reduced pressure area 7 from the deflected area 4 upper part when is settled in the supporting seat 9.

The supporting seat 9 is situated at the place of the deflected area 4 upper part connection with the reduced pressure area 7. The seat is to the best advantage made in the form of incomplete ring (fig. 7) or two incomplete halves of the ring (fig. 8). The supporting seat 9 is formed at the intersection of the deflected area 4 upper part edge with the reduced pressure area 7 and/or in the internal side of the corner wall 8, connecting the deflected area 4 upper part with the through-channel 2. The passage width of the supporting seat 9 in most favourable realisation should be approximately equal to the through-channel 2 width and should be free of sharp edges (fig. 7 and fig. 8). It prevents the valve according to the invention from blocking by the solid particles contained in the liquid stream flowing through the valve, especially in raw waste water. Connecting of the protrusion 5, which performs the role of the ball 1 guide bar on its way of movement from the closed position to the fully open position, with the supporting seat 9 should be made in a smooth manner as shown in fig. 1-5. There are also shown in fig. 1-5 different variants of the supporting seat 9 placement in relation to the protrusion 5, wherein fig. 1, 2 and 4 present the supporting seat 9 made directly in the valve casing, and fig. 3 and 5 show seat made as the independent one being permanently connected to the cover 10.

The solutions of the valves according to the invention as in fig. 1-5 constitute improvements of the valves known from the state- of-the-art, while the solution as in fig. 6 is a new design

characterised in that the external surface of the ball 1 in the fully open position divides the through-channel 2 into two symmetrical parts. The through-channel 2 division into two symmetrical parts is ensured by the supporting seat 9, in which the ball 1 is settled in the fully open position. Such a method of the through-channel 2 division causes lesser distortion of the medium stream in comparison with situation of ball surrounding flow, what promotes the flow energy loss decreasing in the valve. Important feature of the solution is that the ball 1 is guided by four protrusions 5 (fig. 8), made by the edges of intersection of the cylindrical deflected area 4 with the cylindrical through-channel 2, and the supporting seat 9 is situated perpendicularly to the ball 1 movement linear trajectory in the deflected area 4. Furthermore the supporting seat 9, constituted by two incomplete ring halves, is made as separable one. One part of the seat is made in the casing, and the second part is integrated with the cover 10 attached to the deflected area 4 upper part. Such realisation of the supporting seat 9 makes the valve design much simpler and at the same time makes easier the access to the ball 1, as shown in fig. 8. Precise settling of the cover 10 in the valve casing is performed with the aid of the locating pins mounted in the casing.

The operation principle of the valve according to the invention as in fig. 1-6 consists in that under the influence of the liquid stream flow in the through-channel 2, from the inlet side terminated with the ring seat 3 to the outlet, the ball 1 tears away the ring seat 3 and moves toward the deflected area 4 upper part due to pressure difference between the deflected area 4 lower and upper part. This pressure difference, in the way of the ball 1 movement toward the deflected area 4 upper part, is obtained due to part of the liquid stream flowing through the space above the ball 1 and through the reduced pressure area 7. When the ball 1 reaches the level of the supporting seat 9, the reduced pressure action at the corner 6 causes the ball 1 settling in the supporting seat 9. Quick sealing of the ball 1 connection with the supporting seat 9 prevents this valve part against sediment of the pollution, if liquid contains larger solid particles, and ensures greater stability of the ball 1 position.

The non-return valve with moving valve body of the flap realisation shown in fig. 7-13 has the casing provided with the through-channel 2, which inlet is terminated with nest 11, intended for the flap 12 to be settled in the closed position. The casing also

has the deflected area 4 of width greater than the flap 12 width, intended for the flap to be settled in the valve open position. In the inlet, at the place of the deflected area 4 lower part merging with the through-channel 2, the casing has extended cross-section of the flow area connected directly to the through channel 2 and is provided inside with place of the pendulous attachment 13 of the flap 12. In the corner 6, connecting directly the deflected area 4 upper part with the through-channel 2, from the inlet side the reduced pressure area 7 exists, bordered with internal surface of the casing corner wall 8, which connects the deflected area 4 upper part with the through- channel 2. The flap 12, in the fully open position, separates hermetically the reduced pressure area 7 from the side of the deflected area 4 upper part. In one variant of the realisation the flap 12 has on the reverse side the sealing border 14 in the form of horseshoe. The sealing border 14 in the flap 12 fully opened position separates the reduced pressure area 7 from the deflected area 4 upper part by settling the sealing border 14 in the opposite corner wall 8 of the casing (fig. 9). In another variant of the valve realisation the casing corner wall 8 has the settling border 15, connected to the wall, in the form of horseshoe for settling the flap 12 reverse side, provided at both sides with sealing area (fig. 10-12). In fig. 13 the flap 12 reverse side has the separate disc, situated in parallel to the closing disc. The flap 12 reverse side in the fully open position separates the reduced pressure area 7 from the deflected area 4 upper part. The sealing border 14 itself and/or the settling border 15 creates the distance between the flap 12 reverse side and the opposite side of the casing corner wall 8, which distance ensures that at least the tip of the flap, where the borders are opened, is positioned in the flow field of the liquid stream flowing along the through-channel 2 or causes the stream deviation to the opposite side. In fig. 14 the enlargement is shown of the fragment of the flap 12 reverse side, as in fig. 9, with the sealing border 14 in the form of horseshoe opened from the outlet side. In fig. 15 the enlargement is shown of the fragment of the valve casing with the corner wall 8, as in fig. 9-12, and the settling border 15 in the form of horseshoe, connected to the wall. For realisation variants of 90° angle valves, what was marked with bolded broken line in fig. 9-12, the settling border 15, also marked with bolded broken line, has in its internal area the opening of width approximately equal to the through-channel 2 width. For these realisation variants the principal advantage consists in that the

valve blocking by the solid particles contained in raw waste water is practically impossible, moreover the 90° elbow pressure loss promotes the flap 12 reverse side or the sealing border 14 settling in the flow-through settling border 15 even at low flow of liquid stream. The flap 12, shown in fig. 9-12, is mounted in the casing cover 10 in a principally elastic (springy) manner, wherein the flap 12 shown in fig. 9 and 11 can perform limited rotary motion in the place of its mounting on the shaft. In the solutions shown in fig.

9-12 the flap 12 can be made as the rotary one, being mounted on the axle with bearing on both sides, similarly as in fig. 13, with such a difference that the flap 12 tongue is of elastic type. The intermediate solution between the elastic flap 12 mounting with the rubber tongue and rotary mounting on axle with bearings is the version with the flap 12 in the form of the thinner rubber tongue in order to decrease the flap elasticity and to simplify its deflecting even at minimal liquid flows through the valve. In the 90° angle realisation of the flap valve according to the invention the liquid stream influences the large surface of the flap 12 in nearly perpendicular direction, what ensures quick and reliable flap settling in the nest 11. The 90° angle realisation of the flap valve, shown in fig. 12, ensures simplified operation, in comparison to the linear flap valve, due to the possibility of simple taking down the valve from the pipeline and replacing the flap 12 by disassembling the sectional valve casing. The operation principle of the valve according to the invention, shown in fig. 9-13, consists in that under the influence of the medium flow along the through-channel 2 from the inlet with nest 11 toward the outlet, the flap 12 is tore away the nest 11 and moves pendulously around the place of pendulous attachment 13 to the deflected area 4 upper part due to pressure difference between the deflected area 4 lower and upper part. This pressure difference, in the way of the flap 12 movement toward the deflected area 4 upper part, is obtained by flow of part of the liquid stream above the flap 12 and through the reduced pressure area 7. When the sealing border 14 of the flap 12 is situated at the level of the valve casing corner wall 8, the action of reduced pressure in the corner 6 causes the flap 12 sealing border 14 to be settled in the nest 11, as shown in fig. 9. The flap 12 reverse side, having the sealing area on both sides, is settled in similar way in the settling border 15. In 90° angle realisation the flap valve according to the invention as in fig. 9-12 has the settling border 15 with the internal opening, in which the flap

12 is settled in the fully opened position. According to fig. 13 in the settling border 15 the separate disc of the flap 12 reverse side is settled in the fully open position.

The object of the invention is also the method of blocking the liquid flow by means of the moving valve body being settled in closed position in the ring seat 3 or in the nest 11 of the valve according to the invention.

During the liquid flow along the through-channel 2, the moving valve body, situated in the fully open position, is maintained in this position due to principally hermetic closing, performed by the body, of the passage between the deflected area 4 upper part and the reduced pressure area 7. This closing is maintained by pressure difference originating in points in front of and behind the moving valve body in the moment of proper value of the liquid stream flow.

The liquid stream flow to opposite direction is blocked with additional applying of the energy of part of the reverse liquid stream stroke into the closed, principally in a hermetic manner, reduced pressure area 7. This stroke causes the accelerated movement of the moving valve body toward the ring seat 3 or nest 11 and the reverse flow blocking.

Individual parts of the valve casing, as well as the moving valve body, can be made of typical materials, as in case of classic valve designs.

The examples of the valve realisation and the method according to the invention presented above do not cover all possible realisations and applications contained in the patent claims from atoll.