Process Engineering Division – Instrumentation and Automation Section – Daily Question – Question dated 2020-09-20
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Process Engineering Division – Instrumentation and Automation Section – Daily Question – Question from 2020-09-20: Discussion question: 241. What are the two principles to keep in mind when operating the three-valve instrument group?
I think it should be the sequence of opening and closing the manual valve at the time of starting up and shutting down
(1) It is not allowed for the condensed water or isolation fluid in the pressure guiding tube to be lost； (2) The measuring element (diaphragm box or bellows) must not be subjected to pressure or heat.
1. The condensed water or isolation fluid inside the pressure guide tube must not be lost. 2. The measuring element (diaphragm box or bellows) must not be subjected to pressure or heat.
1. Start/stop sequence to prevent pressure on one side only; 2. Condensation after waste discharge to prevent overheating of the diaphragm box
1. The condensed water or isolation fluid inside the pressure guiding tube must not be lost. 2. The measuring element (diaphragm box or bellows) must not be subjected to pressure or heat.
1) It is not allowed for the condensed water or isolation fluid in the pressure guide tube to be lost； (2) The measuring element (diaphragm box or bellows) must not be subjected to pressure or heat
1. The condensed water or isolation fluid inside the pressure guide tube must not be lost. 2. The measuring element (diaphragm box or bellows) must not be subjected to pressure or heat.
(1) It is not allowed for the condensed water or isolation fluid in the pressure guiding tube to be lost； (2) The measuring element (diaphragm box or bellows) must not be subjected to pressure or heat.
1. Start/stop sequence to prevent pressure on one side only; 2. Condensation after waste discharge to prevent overheating of the diaphragm box
First, it is necessary to prevent the condensate or isolation fluid in the pressure guide tube from escaping; second, it is important to avoid subjecting the measuring element to pressure in only one direction.