| 摘要 |
<p>1,126,141. Valves. J. MARX. 21 Sept., 1966 [22 Sept., 1965], No. 42220/66. Heading F2V. [Also in Division G1] A change-over valve, for compound flow meter systems, directs the flow through an auxiliary meter 27 when the flow rate is low and by-passes this meter when the flow rate is high. A primary meter (not shown) is connected to the inlet 3 of the valve casing 1. Within this casing is a shell body 6 which provides a seating 11 for a primary flow responsive valve member 15. This shuts off direct flow through ports 7 to the outlet 4 at low flow rates. In this condition the fluid goes through holes 19 in the valve member 15 and through a seat 12 into a chamber 8, whence the fluid enters the meter 27 and flows round the shell body 6 to the outlet 4. The valve member 15 is slidable on a cylindrical guide 16. When the flow rate has sufficiently increased, an auxiliary flow responsive valve member 21, which is slidably mounted coaxially with the first valve and adjustably loaded by weights 23, rises to close the holes 19. The main valve then opens rapidly from the seat 11 and closes the seat 12 to the meter. The flow passage round the auxiliary valve is tapered inwardly in the direction of flow as shown. A static pressure connection 32 from this passage can be used to operate a brake for the primary meter so that only one meter is working at a time. If the primary meter is placed downstream of the valve, braking is not necessary. However, the low flow is not returned to the outlet 4. The return is blanked off by a partition 35 and the flow led from an auxiliary outlet 34 to a point downstream of the primary meter.</p> |
