Stemless Choke Valve With Sealed Rotator for Sand Wear
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Solution Overview
Problem
Choke valves used in oil and gas production with suspended sand particles experience accelerated wear, necessitating frequent servicing and replacement, and there is a need for a more conveniently adjustable, serviceable, and replaceable valve solution.
Innovation Solution
A stemless choke valve design featuring a hollow cylindrical rotator with a rotator gear, an actuating element, and a variable orifice mechanism, where the rotator is sealed to prevent fluid flow outside the central passage, allowing for rotation of the variable orifice to control flow and incorporating replaceable wear elements for reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional choke valve with stem and actuator is used, then the valve can control fluid flow, but the valve experiences accelerated wear from sand particles and requires frequent servicing
Solution Approach 1:
The valve is divided into modular components: a replaceable orifice assembly separated from the valve body, and a sealed rotator assembly containing moving parts. This segmentation allows the orifice to be replaced without replacing the entire valve, and protects the actuator mechanism from direct exposure to abrasive particles.
Solution Approach 2:
The actuator mechanism (rotator and gears) is extracted from the high-pressure fluid zone and sealed within the valve body, while only the orifice plate remains exposed to the fluid flow. This extraction removes the expensive and complex actuation components from direct contact with abrasive sand particles.
2Ease of operation
If a conventional choke valve with stem is used, then the valve can be actuated, but the valve is difficult to service and adjust
Solution Approach 1:
The orifice assembly is segmented as a separate, easily replaceable component that can be accessed through a service opening in the valve body, allowing quick adjustment of flow characteristics without disassembling the entire valve or dealing with a traditional stem mechanism.
Solution Approach 2:
The rotator gear mechanism is designed to be actuated from the outside through gears that mesh with the sealed rotator, allowing operators to adjust the orifice position without opening the valve body or exposing internal components to the fluid environment.
3Productivity
If a conventional choke valve with stem and actuator is used, then the valve can control flow, but the actuator components are exposed to high pressure and require frequent maintenance
Solution Approach 1:
The rotator and actuator gears are extracted from the high-pressure fluid zone and sealed within the valve body, creating a pressure-tight barrier that isolates these components from direct fluid exposure. This allows the actuation mechanism to operate in a controlled environment, reducing maintenance requirements.
Solution Approach 2:
A sealed barrier (such as an O-ring or piston seal) acts as an intermediary between the high-pressure fluid zone and the actuator mechanism, allowing force transmission while preventing fluid contact with the actuator components.
Data Source
AI summary
A stemless valve includes (a) a valve body having a longitudinal axis and defining a central flow passage and an upper actuator opening; (b) a cylindrical rotator disposed within the central flow passage, and having a rotator gear exposed through the actuator opening, the rotator sealed within the valve body to prevent fluid flow outside the central flow passage; (c) an actuating element passing through the upper actuator opening, and having a actuating gear which engages the rotator gear. Movement of the actuating rod rotates the rotator around the longitudinal axis within the valve body, causing opening or closing of a variable orifice connected to the rotator.