SHUT-OFF VALVE HOUSING

Abstract

A shut-off valve housing having a through-channel extending inside a main body between an inlet opening and an outlet opening, and a valve seat disposed inside the through-channel. To reduce flow losses, an outflow region of the through-channel immediately downstream of the valve seat on an outflow side has an inwardly curved contour.

Claims

1. A shut-off valve housing having a through-channel extending inside a main body between an inlet opening and an outlet opening, and a valve seat disposed inside the through-channel, wherein an outflow region of the through-channel immediately downstream of the valve seat on an outflow side has an inwardly curved contour.

2. The shut-off valve housing of claim 1, wherein the curvature in the outflow region of the through-channel has a transition from the valve seat to the outflow region extending parallel to, or at an angle of <10 with respect to a central axis of the through-channel.

3. The shut-off valve housing of claim 1, wherein the inwardly curved outflow region of the through-channel extends at a radius of curvature R1, with the product of the radius R1 and the quotient of a nominal diameter DN of the shut-off valve housing and an inside diameter Di at the narrowest point of the through-channel having a value between 140 and 400.

4. The shut-off valve housing of claim 1, wherein, along the transition to the valve seat, the outflow region of the through-channel extends tangentially with respect to a seat plane of the valve seat.

5. The shut-off valve housing of claim 1, wherein the outflow region immediately downstream of the valve seat in the direction of flow is adjoined by a further region of the through-channel having an outwardly curved contour.

6. The shut-off valve housing of claim 5, wherein the further outwardly curved region of the through-channel extends at a radius of curvature R2, with the radius R2 and the quotient of a nominal diameter DN of the shut-off valve housing and an inside diameter Di at the narrowest point of the through-channel having a value between 140 and 400.

7. The shut-off valve housing of claim 1, wherein an inflow region of the through-channel disposed on the inflow side of the valve seat has an outwardly curved contour.

8. The shut-off valve housing of claim 1, wherein the inside wall of the main body has a recess for receiving a material for the valve seat, which is applied by deposition welding.

9. The shut-off valve housing of claim 8, wherein the recess is disposed on an inside surface of a protuberance projecting inwardly from the main body.

10. The shut-off valve housing of claim 8, wherein the recess has the shape of a planar annular groove.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Additional features and advantages of the present invention follow from the subsequent description of a practical example with reference to the drawings. The drawings show:

[0012] FIG. 1 a partially sectioned view of a shut-off valve housing;

[0013] FIG. 2 a detail view of the shut-off valve housing shown in FIG. 1;

[0014] FIG. 3 a diagrammatic visualization of the flow inside a shut-off valve housing according to the present invention; and,

[0015] FIG. 4 a diagrammatic visualization of the flow inside a prior-art shut-off valve housing.

DETAILED DESCRIPTION

[0016] FIG. 1 shows a partially sectioned lateral view of a shut-off valve housing 1 of a shut-off valve, which is configured in the form of a butterfly valve and used as a shut-off valve in water pipes. The shut-off valve housing 1 comprises a through-channel 5, which extends inside a main body 2 between in inlet opening 3 and an outlet opening 4, and a valve seat 6 disposed inside the through-channel 5. The through-channel 5, which has a circular cross section, comprises an inflow region 7 disposed upstream of the valve seat 6 and an outflow region 8 immediately downstream of the valve seat 6 on the outflow side.

[0017] The shut-off valve housing 1, which is made of cast iron, another metal, or a plastic material, comprises a lateral bearing flange 9 for the rotary support of a flap- or disk-shaped valve body (not shown) and connecting flanges 10 and 11 on both ends for connecting the housing to pipelines. Disposed in the lateral bearing flange 3 is a bearing bore 12, which extends at right angles with respect to the longitudinal axis of the main body 2, for a drive shaft of the valve body, which is capable of being rotated between a closed position and an open position. The valve seat 6 is a hard-faced valve seat and can be produced with a weld overlay made, e.g., from stainless steel (chromium-nickel alloy). To this end, in the region of the valve seat 6, as shown in FIG. 2, the inside wall 13 of the main body 2 can have a protuberance 14 projecting inwardly into the through-channel 5 and having a recess 15 in the shape of an annular groove disposed on the inside surface for receiving the material which is applied by means of deposition welding.

[0018] As indicated especially in FIG. 2, the inflow region 7 of the through-channel 5 which, as seen in the direction of flow, is disposed upstream of the valve seat 6 first has a continuously increasing diameter and subsequently, up to the valve seat 6, a continuously decreasing diameter. Thus, as seen in the radial direction, the through-channel 5 has an inflow region 7 with an outwardly curved contour, i.e., curved towards the outside surface of the main body 2. In contrast, the outflow region 8 of the through-channel 5, which is disposed immediately downstream of the valve seat 6 on the outflow side, has a radially inwardly curved contour, i.e., curved towards the central axis of the through-channel 5. The inwardly curved outflow region 8 of the through-channel 5 extends at a radius of curvature R1, which is preferably selected in such a manner that the product (R1DN/Di), i.e., the product of this radius R1 and the discharge coefficient, i.e., the quotient of a nominal diameter DN of the valve housing and an inside diameter Di at the narrowest point of the through-channel 5, has a value between 150 and 400. The curvature in the outflow region 8 of the through-channel 5 is designed in such a manner that the transition from the valve seat 6 to the outflow region 8 extends as parallel as possible to the central axis of the through-channel 5 and, thus, as parallel as possible to the direction of flow. This makes it possible to attain a flow path that is as disturbance-free as possible.

[0019] The outflow region 8 of the through-channel 5 with the inwardly curved contour which, in the direction of flow, is disposed immediately downstream of the valve seat 6, is adjoined by a further outwardly curved region 16 of the through-channel 5 so that the through-channel 5 of the shut-off valve housing 1 on the outflow side of the valve seat 6 overall has an S-shaped contour. The radius R2 of the region 13 is preferably selected to ensure that the product (R2DN/Di), i.e., the product of this radius R2 and the discharge coefficient, i.e., the quotient of the nominal diameter DN of the valve housing 1 and the inside diameter Di at the narrowest point of the through-channel 5, has a value between 150 and 400.

[0020] As the flow visualization of FIG. 3 indicates, when the outflow region 8 has an inwardly curved contour, the flow on the outflow side of the valve seat 6 proceeds relatively free from disturbances and without the formation of back flows along the inside wall 13 of the main body 2.

[0021] In contrast, the flow visualization of FIG. 4 indicates that, along the inside wall 13 of the main body 2, back flows and turbulences form on the outflow side of the valve seat 6 when the outflow region has an outwardly curved contour, i.e., curved toward the outside surface of the housing 2.