Mark 50 Series Back Pressure Regulator Seat Adjustment & Operation
In this video, a customer would like to know if the seat on their Mark 50 back pressure regulator should be opened or closed when the valve is not operating.
Video Transcript Summary
The video addresses a common question from users (specifically a customer named Paul with a 3-inch Mark 50) regarding the state of the valve seats during non-operation.
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Question: Should the seats be open or closed when the valve is not operating?
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Answer: On a Mark 50 (and any size back pressure regulator that utilizes sliding gate seat technology), the valve is normally closed. When the valve is not operating, it will be stroked down and the seats will be closed.
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Seat Adjustment Procedure:
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Because the valve is closed at rest, you must adjust the seats while they are in the full open position.
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To achieve this, reach in through the outlet of the valve with a screwdriver.
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Push the back of the disc pin upward until the valve stops opening (reaches its full top travel).
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While held in this full open position, you can then proceed with the seat adjustment.
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How to Set a Back Pressure Regulator?
To set a back pressure regulator, slowly adjust the spring or setpoint screw until the desired upstream pressure is reached. Turning the screw clockwise typically increases the set pressure, while turning it counterclockwise reduces it.
Make adjustments gradually while monitoring the upstream gauge to avoid overshooting your target. Once the required pressure is achieved, secure the locknut (if provided) to hold the setting in place.