Branched valve

Abstract: A branched valve includes a main flow passage and a branch flow passage provided in a main body, a weir provided between the main and branch flow passages, and a valve disc which can contact with and come off from the weir and which selectively connects and disconnects the main and branch flow passages, wherein a branch flow entrance wall of the branch flow passage integrated with the weir has either a flat surface or a convex surface. The outer wall of the branch flow exit of the main flow passage may rise vertically from the outer wall of the main flow passage, and the side wall of the weir is located approximately on the center line of the main flow passage. The branch flow passage may be provided so that the center line thereof is located upper than the center line of the main flow passage. The valve disc may be a diaphragm.

Description: FIELD OF THE INVENTION This invention relates to a branched valve, and in particular to a branched valve used for the branching point in pipe lines for transferring pure water or super pure water used in a fabricating process of a semiconductor device such as ICs, LSls, or super LSls, germ-free water used in a pharmaceutical process, or food relating fluid. BACKGROUND OF THE INVENTION A conventional branched valve has been described in Japanese Patent Provisional Publication (Tokkaisho) No. 151676/87. The branched valve 1 includes a main body 2 provided with a main flow passage 3 and a branch-flow passage 4, a weir 5 provided between a branch flow exit 3A of the main flow passage 3 and a branch flow entrance 4A of the branch flow passage 4, and a diaphragm 6 (valve disc) which selectively connects and disconnects the main flow passage 3 and the branch flow passage 4. A branch flow entrance wall 4B of the branch flow entrance 4A which is integrated with the weir 5 has a recessed surface. However, the conventional branched valve 1 has a disadvantage in that the flux of the branch flow is not sufficient. In the conventional branched valve 1, the branch flow of the fluid which flows into the branch flow passage 4 from the main flow passage 3 is easily peeled off from the branch flow entrance wall 4B just after getting over the weir 5, and makes a turbulent flow. The turbulent flow causes the pressure loss which then causes a large amount of the flux loss. The weir valves disclosed in WO-91/00460 and WO-A-92/00476 have the same disadvantage as the branch flow of the fluid will peel off the weir wall and become turbulent due to the shape of the weir and the branch flow entrance wall, respectively. Further, the conventional branched valve 1 has another disadvantage in that the size is not compact, though the branched valve 1 which is to be connected within i.e. a circulation system of super pure water is desired to has a compact size with sufficient flux of the branch flow. In the conventional branched valve 1, the outer wall of the main flow passage 3 projects largely from the valve center (handle center) to make the width W of the branched valve 1 large, and the lower part of a socket of the branch flow passage 4 projects downward to make the height L of the branched valve 1 large. SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide a branched valve in which generation of the turbulent flow is prevented and sufficient flux of the branch flow is obtained. According to the invention, a branched valve is provided comprising the features defined in claim 1. The valve disc may be a diaphragm. In this branched valve, after getting over the weir, a fluid which flows into the branch flow passage from the main flow passage flows down along the branch flow entrance wall which has a convex surface, without being peeled off from the branch flow entrance wall. Therefore, a turbulent flow is not generated, and the pressure loss and the resulting flux loss are prevented. Accordingly, sufficient flux of the branch flow is obtained. BRIEF DESCRIPTION OF THE DRAWINGS This invention will be explained in more detail in conjunction with appended drawings, wherein: Fig. 1 is a cross-sectional view showing the conventional branched valve. Fig. 2 is a cross-sectional view showing a branched valve in an embodiment according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENT The branched valve according to the invention will be described in conjunction with Fig. 2. The branched valve 10 has a main flow passage 12 and a branch flow passage 13 in a main body 11, a weir 14 provided between a branch flow exit 12A of the main flow passage 12 and a branch flow entrance 13A of the branch flow passage 13, and a diaphragm (valve disc) 15 which can contact with and come off from a top surface (valve seat) 14A of the weir 14 and which selectively connects and disconnects the main flow passage 12 and the branch flow passage 13. The main body 11 which may consist of synthetic resin such as vinyl chloride resin, polyphenylenesulfide, polyvinylidenefluoride or polybutene, for example, is molded integrated with the main flow passage 12 and the branch flow passage 13. The branch flow passage 13 is branched in the direction of about a right angle with the main flow passage 12. A periphery 11A of the main body 11 is for supporting the periphery of the diaphragm 15. The diaphragm 15 which may consist of an elastic material of synthetic resin, for example, can contact with pressure and come off from the valve seat 14A of the weir 14 by rotating a handle 16, and the branch flow which flows into the branch flow passage 13 from the main flow passage 12 is controlled in the flux or shutted off. A bonnet 17 is fixed on the periphery 11A of the main body 11 by a bolt 18 so as to surround the diaphragm 15. A sleeve 19 is supported within the bonnet 17 so as to be allowed to rotate. The handle 16 is fixed on the part of the sleeve 19 out of the bonnet 17. A stem 20 is engaged with the sleeve 19 by screw threads, and the stem 20 can move up and down without rotating by rotating the handle 16 and the sleeve 19. A compressor 21 is connected with an inner part of the stem 20. The center part of the diaphragm 15 is connected with the compressor 21 by a pressing metal 22. The diaphragm 15 can contact with or come off from the valve seat 14A of the weir 14 by stem 20 which moves up and down by rotating the handle 16. A union socket 23 is connected to the branch flow passage 13. A branch flow entrance wall 13B which is integrated with the weir 14 in the branch flow passage 13 has a convex surface. This branched valve 10 may be connected at the main flow passage 12 to an impurity reducing apparatus, a sterilization apparatus, or a circulation system for super pure water processed by a filter and osmotic membrane apparatus, and at the branch flow passage 13 to the use point of either apparatus or system. In this branched valve 10, the sleeve 19 rotates by rotating the handle 16. As a result, the stem 20 which is engaged with the sleeve 19 by screw threads moves down without rotating, and the diaphragm 15 contacts with the valve seat 14A of the weir 14 with pressure, so that the branch flow is shutted off. On the other hand, the branch flow can flow and be controlled in the flux by rotating the handle 16 in the counterwise direction. In this embodiment, the branch flow which flows into the branch flow passage 13 from the main flow passage 12 after getting over the weir 14 flows down along the branch flow entrance wall 13B which has the convex surface without being peeled off from the wall 13B, so that a turbulent flow is not generated. Therefore, the pressure loss due to generation of the turbulent flow and the resulting flux loss is prevented. Accordingly, sufficient flux of the branch flow is obtained.

Claims: A branched valve (10), comprising: a main flow passage (12) and a branch flow passage (13) provided in a main body (11); a weir (14) provided between said main flow passage (12) and said branch flow passage (13); a branch flow entrance wall (13B) of said branch flow passage (13) integrated with said weir (14); and a valve disc (15) which can contact with and come off from said weir (14) and which selectively connects and disconnects said main flow passage (12) and said branch flow passage (13); characterized in that said branch flow entrance wall (13B) integrated with said weir (14) has a convex surface such that the valve disc (15), when in contact with the weir (14), comes into contact with a convex top area (14A) of the weir (14) and, when not in contact, leaves a smoothly widening branch flow entrance area (13A), and in that there is a smooth transit from said top area (14A) to said branch flow entrance wall (13B). A branched valve, according to Claim 1: wherein said valve disc is a diaphragm.

Inventors: SHIGENOBU KATO, YASUO YAMABE, SHIGENOBU, KATO, YASUO, YAMABE
Applicants: SEIKISUI CHEMICAL CO LTD, SEKISUI KAGAKU KOGYO KABUSHIKI KAISHA
Application year: 1993
Main classification: F16K1
IPC codes: F16K7, F16K1