安德森格林伍德內部罐閥門的設計滿足了所有要求美國消防協會,設計和內部安裝閥門，須穿透任何來自外部的壓力管道噴嘴的失敗將導致超出了關閉閥門本身的內部座位。
Internal Tank Valves (ITV) Liquid Storage: LNG, LPG, NH3, LOX
- Description
- Specifications
- Documentation
The Anderson Greenwood Internal Tank Valve is designed to satisfy all of the requirements of NFPA No. 59A for this type of installation, specifically, paragraph 6333:
“The design and installation of an internal valve shall be such that any failure of the penetrating nozzle resulting from external pipe strain will be beyond the shut-off seats of the internal valve itself. ”The ITV is designed for long trouble-free life. Design features are simple yet rugged to withstａnd the rigors of construction. No maintenance of the ITV is required after installation.When mounted on the tank bottom, this valve allows near 99% withdrawal of liquid. It does not depend upon counter-weights or actuator forces for closing. The fail-safe condition of the ITV is closed.
A block valve is always to be provided in series with this valve. The downstream block valve must be closed before the ITV can be opened. This prevents the ITV from being opened on an open or ruptured downstream line.
Seal ruggedness and long life are evaluated as more important factors than absolute leak tightness.
The seal may be installed as a separate unit. The use of this valve increases safety, minimizes property requirements, and should lower insurance liability.
Features & Benefits:
- Fail Safe Isolation – The Internal Tank Valve is a fail-safe isolation valve for bottom and side withdrawal tanks. It is always in a position such that the weight of the disc will close the ITV?when not being held open by the operator.
- Self Seating Disc – The 4" to 18"[100 to 450 mm] pivot type ITV disc is free to pivot within the actuating arm and therefore sits freely on the circular Teflon® seal. The 6", 12", 24" and 30" [150, 300, 600, 750 mm] plug type ITV maintains a constant geometric relation between spherical disc face and conical seal. These design features permit perfect seating regardless of minor misalignments.
- All SS Construction – All materials are proven fully compatible with cryogenic temperatures. To ensure weld and thermal compatibility in service, the orifice plate material is of the same type as the tank bottom and is usually customer furnished. Rotating joints have one surface coated with Teflon®.
- Net Force On Tank Bottom Is Down – The cable force produced by the open and close operators is intentionally limited so that it can never exceed the total weight of the installed ITV. In this way we assure that up-loads will not damage the tank bottom.
- Redundant Open Cable – Completely redundant opening cables are provided so that the valve may be manually operated should the need occur.
- Pressure Equalizing Pilot Valve – The first motion of the open operator opensa pilot valve integral with the valve disc. Product flows through the pilot valve and fills pipe to the downstream block valve, equalizing the static differential pressure across the ITV disc. The force limited operator will stop until pressures equalize at which point the opening operator will continue.
- Anti-Vortex Vanes – A series of radially positioned flat plates are provided to counter the Coriolis Effect and thus prevent lowered pressure and resulting product gasification during withdrawal.
- Position Indication Switch Option – Anderson Greenwood can provide explosion-proof limit switches (NEMA Type 7, Class 1, Groups C and D) mounted on the open operator to indicate valve position (open or closed).
- Auxiliary Close Cables – Close cables are provided to augment normal sealing forces and to improve the manipulative flexibility of the system.
- Control Panel Option – Anderson Greenwood can provide all necessary components for control of the ITV in a single weather-tight enclosure designed for roof installation and remote operation.
Pivot Type Internal Tank Valve: 4" to 18"
Plug Type: 6", 12", 24" and 30"
Side Mounted Pivot Type Internal Tank Valve: 12" to 18"
