US2791396A - Butterfly valves - Google Patents

Description

May 7, 1957 K. REPFVEIIRT 2,791,396

BUTTERFLY VALVES Filed Aug. 20, 1954 2 Sheets-Sheet l May 7, 1957 Filed Aug. 20. 1954 K. REPPERT BUTTERFLY VALVES 2 Sheets-Sheet 2 BUTTERFLY VALVES Karl Reppert, Heidenheim (Brenz), Germany, assignor to Firma Johannes Erhard, Heidenheim (Brenz), Germany, a corporation of Germany Application August 20, 1954, Serial No. 451,240 Claims priority, application Germany August 24, 1953 4 Claims. (Cl. 251-175) The present invention relates to butterfly valves for controlling fluids flowing in pipe lines.

In the co-pending patent app1ication,-Serial No. 399,419, filed December 21, 1953, butterfly valves are disclosed for the shutting off of pipe lines, in which valves a flap is rotatably mounted on a fixed axis. The main characteristics of the flap reside in the fact that the latter is provided with a separate flap packing ring which is mounted by means of supporting members and rubber buffers, resilient members, or the like, and which is displaceable in axial direction .on the periphery of the flap.

It is one object of the present invention to provide a butterfly valve which amounts to a further development of the above disclosed'butterfly valve and to provide in the case of changing flowing direction a one piece casing with a single casing seat; this arrangement brings about the advantage that independent from the prevailing flow direction a closing angle of 90 is only necessary for the closing of the flap.

It is also another object of the present invention to provide a flap in a butterfly valve which includes a separate flap packing ring and in which the said flap has 2. preferably annular recess behind the flap packing ring, which recess is in communication with the rear face of the flap packing ring by means of specially provided borings, the said recesses being provided selectively in the flap packing ring, while the borings are disposed in the flap itself.

It is still another object of the present invention to provide a clamping ring which covers the flap packing ring, displaceable axially, at the rear side of the latter, the said clamping ring extending preferably with its outer edge towards the flap packing ring.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawings, in which:

Figure 1 is an axial section of the construction of a butterfly valve in accordance with the present invention; and

'Fig. 2 is a section through a part of the flap, shown at an enlarged scale. I

Referring now to the drawings, the present butterfly valve comprises a casing 1 which carries the casing seat 2. The flap disk 3 carries the flap seat 4, and the seats 2 and 4 are devised in such manner that spherical seating faces are formed. The flap disk 3 is rotatably mounted on a fixed axis 5.

The normal and forwardly directed flow direction of the medium to be stopped is indicated in the drawing with Pv, while the arrow Pr indicates the opposite flow direction of the medium, as it is possible in connection with alternating flow directions.

A flap packing ring 6 is inserted in the flap disk 3, which flap packing ring 6 carries the flap seat 4 and permits relative movement to a certain extent to the flap disk 3, as will be pointed :out more clearly below in the description of Fig. 2 of the drawing.

A clamping ring 7 is fixedly secured by means of screws nited States Patent 2,791,395 Patented May 7, 1957 8 to the flap disk 3. A recess 12 is provided behind the flap packing ring 6, which recess 12 is in communication with the rear side of the flap packing ring 6 by means of the borings 13 and 14.

Referring now to Fig. 2 of the drawing, the recess or chamber 12 may be easily recognized, which chamber is achieved by providing an annular recess in the flap packing ring 6.

The elastic connection .of the flap packing ring 6 on the flap disk 3 is brought about by means of guide bolts 10 which are permanently screwed into the flap packing ring 6, whereby inserted, elastic intermediate members 9 serve as resilient means. These resilient means are shown in Fig. 2 as particular disk-like spring members. It is, however, also possible to provide in their place rubber buffers or otherwise shaped spring bodies. The clamping ring 7 serves as counter-bearing for the elastic intermediate members 9 and the flap packing ring 6. An undesirable penetration of the medium from one side of the pipe line to its other side through the recess 12 and the borings 13 and 14 is prevented by means of a packing 11a on the ring face a, by a packing 11b on the ring face b, by a packing 110 on the ring face 6, and by a packing lid on the ring face at.

During normal forward movement of the flowing medium in the direction of the arrow Pv, the flap packing ring 6 and, thereby, also the flap seat 4, is pressed in axial direction Pv and this axial movement presses the flap seat 4 very tightly unto the casing seating ring 2 under the influence of the medium, thereby achieving an absolute tightness of the flap disk 3. The latter assumes in this position as a carrying element for the main pressure, while the flap packing ring 6, as sealing element, is pressed toward the casing seating ring 2 only with the force required for achieving the sealing.

In case of reversed flow in the direction indicated by 'i ice the arrow Pr a pressure is exerted in the recess 12 of the flap packing ring 6 in a direction opposite to the flow direction in the closing position of the flap by means of the borings 13 and 14 disposed in the flap disk 3. In this manner the flap disk ring 3 is pressed unto the casing seating ring 2 against the direction of flow P1- and an absolute scaling is achieved.

In both above mentioned closing positions, the packings 11a, 11b, 11c, and 11d prevent the penetration of the working medium from one side to the other.

The closing movement of the flap packing ring 6 towards the engaging face of the clamping ring 7 is extremely small. In order to indicate, however, that such axial movement of the flap packing ring 6 is provided for, Fig. 2 of the drawing, which is drawn at enlarged scale, shows the engaging faces of the flap packing ring 6 and the clamping ring '7, respectively, spaced apart at a distance r. This play of the flap packing ring 6 permits of a very tight seal between the casing seat 2 and the flap seat 4 and is brought about by the pressure exerted by the fluid upon the flap packing ring 6 upon reaching the closed position of the valve. It is quite clear that the rear face a of the flap packing ring 6 will be very slightly, and in particular for the same amount, lifted from the engaging face of the flap disk 3, as the flap packing ring is advanced toward the engaging face of the clamping ring '7, without, however, interfering with the ielfective operation of the packing 11a between the two last mentioned faces. The actual axial movement of the flap packing ring 6 is smaller in length than the distance 1; between the engaging faces of the flap packing ring 6 and the clamping ring '7 in their initial position, that means before the fluid pressure is applied to the flap packing ring 6, since a complete sealing between the casing seat 2 and the flap seat 4 must be achieved before the available distance s is used up.

It is thus clear that due to the operationof the elastic members, the flap packing ring 6 will assume in all open positions of the flap disk 3 the extreme right position (Fig. 2'), in which the rear face a of the flap packing ring 6 will engage closely the adjacent face of the flap disk 3, while its front face will be spaced apart from the rear'face of the clamping ring 7 for the full amount s.

If during closing of the valve the closing position of the flap disk 3 is reached, only then takes place the mentioned axial movement of the flap packing ring 6 and before exhausting the available distance s for such movement, a tight sealing between the casing seat 2 and the flap seat 4 is already achieved. As also shown in Fig. 2, the casing seat 2 and the flap seat 4 are also, however, still more slightly spaced apart for the distance s,, in said initial position of the flap packing ring 6. The distance s, is shown in Fig. 2 rather exaggerated for better demonstration, since it is in fact so small that it cannot be recognized with the free eye.

If, now, the flow of direction of the fluid is that of the arrow Pv (Fig. 2), the pressure force exerted by the fluid which moves the flap packing ring 6 towards the left correpsonds with the annular cross-section A. If, however, the flow of direction of the fluid is that of the arrow Pr (Fig. 2), the pressure force exerted by the fluid which moves the flap packing ring 6 towards the left, that is in the same direction as achieved in the flow of the fluid in opposite direction, corresponds with the annular cross-section B. The movement of the flap packing ring 6 in the same direction as before is brought about by means of the recess 12 and the borings'l3 and 14 which again permit application of the fluid pressure at the rear face of the flap packing ring 6. The packings 11a and 110 amount to the limiting means for the respective annular pressure areas A and B The present structure functions in such manner that in all open positions of the flap disk ,3 the force of the elastic members 9 surpasses that of the fluid pressure, and only just before the closing position of the flap disk 3 is reached, the fluid pressure, being no more balanced on both sides of the flap disk 3, prevails over the force of the elastic members 9, regardless whether the annular pressure area A or annular pressure area'B is effective, responsive to the flow of direction of the fluid. Accordingly, the axial movement of th flap packing ring and, thereby, a sealing between the seats 2 and 4 is achieved.

The structure of the butterfly valve in accordance with the present invention permits of application not only for liquids but also for media consisting of gases. Constructive details may vary from the construction shown in the drawings without leaving the scope of the present invention. For instance, the choice of the material to be used for the respective parts may be chosen in accordance with the particular application and is of no importance for the present invention.

The material and formation of the elastic bodies 9, are likewise of no importance, which bodies 9 may be made rubbe butters o othe re il e t lement F thermore, the screws 8 may be replaced by other construction elements, as for instance, rivets or the like and the screw bolt 10 may also be mounted in the clamping ring 7. In case only low pressures are encountered, the screw bolt 10 may be eliminated entirely.

In all instances, the pressure face of the flap packing ring 6 formed by the recess 12 is greater than the pressure face disposedon the opposite side andformed by the end face of the flap seating ring 4.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

1. A butterfly valve including in combination, a casing having a valve seating, a flap disk movable in said casing from an open inoperative position into closing, said valve seating engaging and operative position, a flap packing ring resiliently and axially movably mounted on the said flap disk, a flap seating mounted on said flap packing ring and engaging the said valve seating in the closed position of the valve and adapted to be urged by the static pressure of the shut-off medium into better contact with said valve seating by axial movement of the, said flap packing ring, the said flap disk and said fiap packing ring defining a chamber and said flap disk having borings communicating the said chamber with the front face of the said flap disk, in order to bring about axial movement of said flappaeking ring in the same direction independently of thedirection of flow of fluid and the fluid pressure urging said flap-packing ring together with said flap seating toward said valve seating so as .to increase the contact between said valve seating and said flap seatmg.

2. The valve, as set forth in claim 1, in which the said chamber is formed by a recess disposed in the said flap packing ring and the said borings are disposed in the saidfiap disk.

3. The valve, asset forth in claim 1, which includes a clamping ring covering the front face ofthe said flap packing ring and extending with its outer edge to the said flap seating.

4. The valve, as set forth in claim 1, which includes resilient means disposed between ,said flap packing ring and'said clamping ring, in order to bring about said resilient mounting of said flap packing ring.

References Cited in thefilepf this patent UNITED STATES PATENTS 1,591,903 White July 6, 1926 1,860,619 Pfau May 31, 1932 FOREIGN PATENTS 237,059 Switzerland of 1945

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