JPS5884313A - flow control device - Google Patents

Abstract

PURPOSE:To secure the reliability of the flow rate control for a long period of time, by exercising a stepped control over the flow rate of a separate cascade by means of an ON/OFF valve. CONSTITUTION:For a separate cascade which has no trouble even with the + or -5% fluctuation of the rated flow rate, the ratio of the flow rate that can be supplied to flow rate throtting mechanisms 2-5 like orifices, etc. is set at 80, 20, 10 and 5% of the rated flow rate. Thus various different flow rates can be obtained from the combinations of the above-mentioned flow rate ratios. In other words, the flow rate ratio is set with every 5% and at maximum 115% at the level near the rated flow rate. Thus the following advantages are obtained by controlling the flow rate by opening and closing the ON/OFF valves 6-9. First, the solenoid valves are available to the ON/OFF valves to increase the reliability, and an electrical function suffices. Second, the accuracy is improved for the flow rate, and at the same time the control is facilitated for the flow rate in spite of a stepped control. Third, the maximum flow rate that gives no trouble to the main body of a gas separating cascade can be selected by means of a fail-open valve even if all valves have troubles.

Description

[Detailed description of the invention] The present invention relates to a flow rate control device.

For example, a gas separation cascade is known as a device for separating a mixed gas of heavy gas components and light gas components into each component gas. The method of controlling the flow rate of this gas separation cascade is generally to install a control valve to control the flow rate, but in this case, the control valve has low reliability.
If long-term reliability is to be ensured, it is necessary to arrange multiple units in parallel. This will cause an increase in costs.

The present invention uses an on-off valve to control the flow rate of the gas separation force scale V in steps;
Section M1! It is an object of the present invention to provide a flow rate control device for a gas separation cascade that can ensure i-characteristics. In other words, the on-off valve itself is more reliable than the control valve, and even if the valve remains out of order, it is possible to limit the flow rate, which is advantageous for live women.

The configuration of the present invention will be explained below with reference to illustrated embodiments. As shown in the figure, in the gas supply section of the gas separation cascade l, flow rate restricting mechanisms 2 to 5 such as orifices and on/off valves 6
.about.9 connected in series are connected in parallel (Figure 1 shows the case of 4 parallel connections). Then, the on/off valves 6 to 9 are opened or closed to adjust the flow rate in steps.

Next, the effect will be explained. In the separation cascade, the performance is not impaired even if the flow rate is ±5% of the rated value.
If the proportion of the flow rate that can flow through each of the orifice equal flow rate restricting mechanism types -5 is, for example, 80%, 20%, 10%, and 5% of the rated flow rate supplied to the gas separation cascade, various flow rates can be obtained by combining these. That is, 80%, 85%, 90%, 95%, 100% near the rated flow rate.
, 105% flow rate is obtained in 5% steps, and the maximum flow rate is 1
It becomes 15%. Using an on-off valve in this way and adjusting the flow rate by opening and closing the valve has the following advantages. First, a solenoid valve can be used as an on/off valve.

More reliable than continuous control valves. It is also electrically actuated and no other utilities such as air are required. wI&
2. The accuracy of the flow rate is determined by the flow rate restriction mechanism such as the orifice.
Good accuracy. Also, although it is step-wise, the flow rate can be easily adjusted by simply turning it on and off. Then, we use a fully open valve for @3 so that even if all the valves fail and become open, the maximum flow rate will not affect the gas separation cascade body at all.
For example, it can be selected to be 115% of the above example.

Further, in this embodiment, a flow rate restricting mechanism such as an orifice is used, but these may be pipes themselves of different sizes. Furthermore, although the explanation has been made assuming that the present invention is applied to a gas supply section of a gas separation cascade, it may also be used in a product section that is an outlet section.

As described above, according to the present invention, a reliable flow rate control device for a gas separation cascade can be provided.

[Brief explanation of drawings]

The figure is a piping system diagram showing an embodiment of the flow rate control device according to the present invention. 1 Gas separation cascade 2-5 flow rate throttling mechanism 1 On-off valve

Claims (1)

[Claims] 1. A flow control device comprising a plurality of series-connected pairs of a flow rate restricting mechanism and an on/off valve provided in either or both of a supply section and an outlet section and arranged in parallel.