AL/DK & AL 200

AL/DK & AL 200

Vent Valve, Lift-actuated

Función y Descripción

PROTEGO® lift-actuated vent valves type AL/DK provide automatic venting of floating roof tanks when the floating roof is lowered on its supports and the tank is either finally drained or refilled. When the floating roof is in its lowest position the valve is forced to open through lift actuation and this prevents unacceptable vacuum during final draining or unacceptable pressure during refilling.

In general the device consists of a housing (1) with sheet-metal panel to be welded on the floating roof, two or four connection nozzles (2) for installation of vent caps, cover (3), lift (4) including valve pallet (5), lift pipe (6) and the condensate drain valve (7) which can be flame transmission proof if required. A flat gasket is attached to the valve pallet (5) to provide sealing. The cover (3) is sealed by a sealing cord (8).

In general the device PROTEGO® AL 200 consists of a housing (1) with sheet-metal panel to be welded on the floating roof as well as the valve seat (2), lift (3) including valve pallet (4) and lift pipe (5). A flat gasket (6) which provides sealing.

As the lowest position of the floating roof varies for operation and assembly specify the dimensions h1 and h2:

h1: Distance between lower edge of sheet-metal panel (or mounting flange) and tank bottom in lowest position of floating roof (operating position with an empty tank).
h2: Distance between floating roof in lifted maintenance position and height of floating roof in fully lowered operating position, if the tank is empty.

If the floating roof supports are changed from operating position to maintenance position the lift has to be lengthened as well. This is done with an adjustable locking pin that is secured with a bolt. The valve is not flame transmission proof.

A hazard analysis (which considers the material selection and function of the device) shows that the device doesn’t have any potential sources of ignition. Therefore they are not subject to the European Explosion Protection Directive 94/9/EC when used in explosive atmosphere.

AL/DK & AL 200
AL/DK & AL 200

Data Necessary for Specification

Stored product Tank diameter (m or ft)
Tank height (m or ft)

Support height h1 (operating position with empty tank)
Support height h2 (lifted assembly position)

Maximum allowable tank pressure pT (mbar or inch W.C.)
Pump rate (m³/h or CFH)

Selección y Diseño

The required quantity and nominal size DN will be defined based on the calculated flow rate from the thermal venting and pumprate in lowest floating roof position (Nm³/h or CFH) and based on the maximum acceptable tank pressure pT (mbar / inch W.C.) according to the flow capacity charts. Special models are available on request.Flow rates and pressure losses of vent caps PROTEGO® BE/HRor PROTEGO® LH/AD have additionally to be taken into account according to the appropriate charts in the relevant data sheetsor operating instructions. Lift-actuated vent valves PROTEGO® AL 200 can be applied incase just venting is required.

AL/DK & AL 200

Diagrama de flujo volumétrico

Los diagramas de flujo volumétrico han sido determinados con un banco de pruebas de caudal calibrado y certifi - cado por TÜV. El flujo volumétrico V. en [m³/h] y el CFH se refi eren a las condiciones estándar de referencia de aire según ISO 6358 (20°C, 1bar). La conversión a otras densidades y temperaturas están referidas en el Vol. 1: “Fundamentos Técnicos”.

AL/DK & AL 200

Application Examples for PROTEGO® AL/DK

Lift-actuated vent valves of type PROTEGO® AL/DK can be combined with vent caps type BE/HR which are deflagration proof and resistant against endurance burning. This ensures flame transmission proof ventilation.

If resistance against endurance burning is not required the valves can alternatively be combined with PROTEGO® deflagration proof devices type PROTEGO® LH/AD. The applicable data sheets are available in volume 2 “Deflagration Flame Arresters, end-of-line and Vent Caps”.

Application Examples for PROTEGO® AL 200

PROTEGO® AL 200 for fixed roof storage tanks with internal floating roof.

AL/DK & AL 200