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Conceptual Self Acting Temperature Controlled Valve Actuator Oil & Gas Upstream up to 3000psig

Discussion QuestionsConceptual Self Acting Temperature Controlled Valve Actuator Oil & Gas Upstream up to 3000psig
Tamunofiniarisa Staff asked 4 years ago


Whenever hot reservoir fluid is at the surface in the Flowline, the high-temperature signal is transmitted through the
thermocouple connection to the Actuator Controller unit; which activates the closure of the control valve. Otherwise,
whenever there is no flow of hot reservoir fluid at the surface and the flow line temperature drops, the control valve return to
its normally open position.

We need you to design and fabricate an ACTUATOR CONTROLLER to achieve this objective or if you have an alternative device that can



1 Answers
Tamunofiniarisa Staff answered 3 months ago
From all indications the only challenge is the controller, and for me, the actuator does not need actual process gauge pressure (psig), which is 2500 as per your design.

Nonetheless, dear uncle, the Main Flow Control Valve’s actuator does not need that much pressure to travel the valve plug. By that I mean, the bellows assembly, return spring, or cylinder, etc. in the valve stem determines the counterbalance force beyond which drives the valve to close or to open as the case may be.


From what I understood pertinent to the problem at hand, the  ACTUATOR that would need External Power for control is not okay since the installation will be upstream, and on most remote platforms.


Now, due to work pressure, I could not have time to sketch; but read what I thought out carefully and I am within 95%-98% confidence interval that it would work.


The most important parts are:

  1. Capillary Tube (Flexible) is operable at High Pressure at least (100-350psig).
  2. 5-way direction control (Direct Acting ) Valves with spring return. See images below.
  3. Associated Tubings (Impulse Lines).
  • THE CAPILLARY FLEXIBLE TUBING: This shall come with the temperature system (A thermowell without an electrical connection). Instead, it is fitted with the tube filled with volatile temperature-sensitive gas (vapour tensioned, since it is for gas operations). This system will generate the necessary pressure to control the 5-way direction control valve.

Inline images 1

The valve above is an example of a closed centre valve. Open centre valves are also available as shown below

  • As per the diagrams above the valve is NORMALLY CLOSE when no pressure is sensed from the Capillary (Note that some modification is required to enable the capillary to drive the valve spool without loss of vapours in the capillary tube).
  • Ports A and B control the MAIN FLOW CONTROL VALVE by allowing or blocking flow on Main Valve Actuator. The “PUMP” in the diagram is where the pressure is tapped from (High-Pressure Line) Upstream the Gas Line and reduced to 250psig or depending on the operating pressure of the MAIN CONTROL VALVE.

Open in Centre

  • THE 5-WAY DIRECTION CONTROL VALVE: This allows upstream fluid tapped through a PRV (Pressure Reducing Valve) from 2500psig to 250psig used to move the Valve Cylinder.
  • Now, very importantly, the inlet and outlet of the control pressure are decided by the Thermosystem and Capillary Tubing as aforementioned. But the big deal here is there is no Instrument Air to control the valves. The main Gas lines are used for the control and that is a major concern.
  • Hence, the vents are redirected to the Low-Pressure Line Downstream of the Gas Line along the flow to avoid loss of Gas. That is what should be experimented with if no SAFETY ISSUES, then we are good to go.

I shall furnish you with further details based on this as we progress.

Thank you and warm regards

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