SU1541563A1 - Device for control of liquid flows - Google Patents

Abstract

The invention relates to the field of automation of chemical technology processes and can be used to control liquid streams in systems requiring high process reliability, in particular in the process control system for producing corrosive liquids with the qualification of secondary purity. The purpose of the invention is to increase technological reliability in controlling the flow of aggressive liquids of the qualification of secondary purity. In the device, each diaphragm valve 1 is provided with an additional diaphragm 8 rigidly connected to the working diaphragm 5 by means of a rod 9 and forming a sealed cavity 10 connected through an inductor 11 and a switching valve 12 to an inert gas flow line 13 and to the first input of a differential pressure gauge 14 connected the second entrance with line 13 flowed. A pressure gauge 14 is connected via an analog-differential converter 15 to an additional control and indication unit. The device has a high technological reliability and it eliminates the need for scheduled preventive repairs. 1 il.

Description

 The invention relates to the field of automation of chemical technology processes and can be used to control liquid streams in systems requiring high process reliability, in particular in the process control system for producing corrosive liquids with the qualification of secondary purity.

The purpose of the invention is to increase technological reliability in controlling the flow of aggressive liquids of the qualification of secondary purity.

The drawing shows a diagram of a device for controlling fluid flows.

The device contains at least two diaphragm valves 1, each of which consists of a housing 2 with channels 3 and a liquid inlet and outlet, a working diaphragm 5 and an actuator 6 connected to the control unit 7, and the valve also has an additional diaphragm 8 rigidly connected to the working membrane 5 by means of the rod 9 and forming a sealed cavity 10 with it, which is connected via the throttle 11 and the switching valve 12 to the inert gas flow line 13 and directly to the first input of the corresponding differential manometer AND A second input with a line 13 flows, and the outputs of differential pressure gauges are connected by analog-digital converters 15. Controller 16, interface blocks 17, digital display 18 and alarm unit 19 are included in an additional unit.

The device works as follows.

With the help of control unit 7 OCU7

liquid flows are controlled by a given program by acting on the actuators 6 diaphragm valves 1. At the same time, $ 0

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There is continuous diagnosis of the valve system.

Valve system diagnostics is performed by inert gas supply from the leakage line 13 through switching valves 12 and throttles 11 into the sealed cavities 10 of the membrane valves 1. The pressures in the sealed cavities 10 and the leakage lines 13 are compared using differential pressure gauges 1.

In case the membranes 5 and 8 are not torn and do not have microcracks, the pressure in the cavity 10 will be equal to the pressure in the line 13 of leakage. In the event of ruptures or microcracks in the membranes due to leakage of inert gas, the pressure in cavity 10 becomes lower than the pressure in line 13 of leakage. At the same time, the output of the corresponding differential pressure gauge, through the corresponding analog-digital converter 15, sends a signal to an additional control unit, by means of which the corresponding valve is blocked and information is given about the failure of this valve.

The sensitivity of diagnosing diaphragm valves depends on the volume of the sealed chamber 10, the conductivity of the throttles 11 and the magnitude of the overpressure (pressure in the leakage line 13. By creating overpressure in the chamber 10 in case of a rupture of the working membrane 5, the flow of fluid from the working system to the external environment is excluded. Exclusion of fluid from The working system into the external environment is also provided by the introduction of an additional membrane 8.

Thus, the improvement of the technological reliability of the device is carried out, and the need for scheduled preventive repairs is also eliminated, which significantly

reduces system maintenance costs.

Claims (1)

Formula image, t and N and A device for controlling fluid flows, comprising a control unit and diaphragm valves, each consisting of a housing with inlet and outlet channels for the working fluid, a working diaphragm and an actuator connected to the control unit, in order to improve process reliability under control The flow of aggressive liquids, it contains an additional control and indication unit, throttles, switching valves, differential pressure gauge. ten 15 analog-to-digital converters according to the number of diaphragm valves, each valve being provided with an additional diaphragm rigidly connected to the working diaphragm via a stem and forming an airtight cavity connected to it through a series-installed choke and switching valve with an inert gas leakage line and directly to the first the input of the corresponding differential pressure gauge, connected by a second input to the inert gas flow line, the outputs of which through an analog-to-digital converter p Connected to the additional control and display unit, the output connected to the switching valve.