Zimbabwe National Oil Infrastructure Company (NOIC) Tank Farm Project
This article is based on a tank farm project of the Zimbabwe National Oil Infrastructure Company (NOIC), focusing on practical challenges in pipeline isolation and maintenance switching, including flammable media, the requirement for pressurized operation, and high reliability under outdoor conditions.
The solution involves a 10" 150LB swing type line blind valve, designed in accordance with ASME B16.34, with WCB cast steel body and metal sealing tested to API 598 zero leakage standards. Combined with worm gear operation and an anti-misoperation mechanism, the valve enables positive isolation switching without depressurization or shutdown.
1) Flammable Medium with High Safety Requirements
The transported medium is petroleum. Any leakage may result in serious safety incidents. Therefore, high sealing integrity and operational reliability are required.
2) Requirement for Isolation Under Pressure
Conventional valves cannot provide positive isolation without depressurization during maintenance. Depressurization leads to operational interruption, product loss, and additional restart costs.
3) Outdoor Installation with High Reliability Demand
The valve is installed in an outdoor station. It must withstand site environmental conditions and ensure stable operation with controlled risk of misoperation over long-term service.
To address the above conditions, Dervos Valve supplied a 10" 150LB swing type line blind valve with the following key design features:
1) Design Standard and Material
The valve is designed and manufactured in accordance with ASME B16.34. The body material is WCB cast carbon steel, suitable for petroleum service conditions, with a temperature range of -29°C to 150°C, offering adequate corrosion resistance and mechanical strength.

2) Sealing Performance
The sealing pair adopts a precision-machined soft sealing structure, tested in accordance with API 598. It achieves reliable zero leakage under petroleum service conditions, ensuring safe pipeline isolation.
3) Swing Type Blind Structure
The swing blind plate allows switching between flow and blind positions without pipeline disassembly or depressurization. This enables rapid transition and solves the limitation of conventional valves in achieving online positive isolation.
Swing Type Blind Technical Drawing
4) Operation and Safety Design
Equipped with a worm gear operator and anti-misoperation device, the valve ensures smooth manual operation with clear position indication, minimizing the risk of incorrect operation in field conditions.
After commissioning, the solution delivered the following benefits:
1) Reliable Isolation Performance
The valve meets API 598 leakage requirements. No leakage has been observed during operation, ensuring safe pipeline performance.
2) Improved Maintenance Efficiency
The swing type structure enables online isolation without depressurization. Maintenance time is significantly reduced, minimizing production interruption.
3) Controlled Operational Safety
Clear blind position indication and anti-misoperation design reduce risks for field operators, aligning with safety management practices in oil & gas facilities.
In this project, Dervos Valve provided a swing type line blind valve solution that achieves safe isolation under continuous operation in petroleum service. The solution ensures long-term sealing reliability and meets the project's requirements for safety, reliability, and operational efficiency in national oil infrastructure applications.
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