Caractéristiques
Fonction et description
Automatic Venting Valves for Floating Roof Tanks
PROTEGO® Lift-Actuated Vent Valves Type AL-DK provide automatic venting of floating roof tanks when the floating roof is lowered onto its supports and the tank is either drained or refilled. When the floating roof is in its lowest position, the valve is forced to open through lift actuation, which prevents inadmissible vacuum during final draining or inadmissible pressure during refilling.
Design of Valves
The PROTEGO® AL-DK valve consists of a housing (1) with a sheet metal panel to be welded onto the floating roof or a flange for mounting on a mating flange, two or four connection nozzles (2) for installation of vent caps, cover (3), lift (4) including valve disc (5), lift pipe (6), and the condensate drain valve (7) which can be designed to be flame transmission proof. The condensate drain is sealed by a flat gasket attached to the valve disk (5). The cover (3) is sealed by a sealing cord Dichtschnur Die Dichtschnur ist eine Schnur aus Kunststoff, mit kreisförmigem oder quadratischen Querschnitt. Sie wird zur Abdichtung von Bauteilen eingesetzt. (8).
Dimensions for Different Floating Roof Heights
As the lowest position of the floating roof varies for operation and assembly, specify the dimensions h1 and h2: h1: Distance between the lower edge of sheet-metal panel (or mounting flange) and the tank bottom in lowest position of floating roof (operating position with an empty tank). h2: Distance between the floating roof in lifted maintenance position and the height of the floating roof in fully lowered operating position (operating position with an empty tank).
Conversion of Floating Roof Supports and Extension of the Plunger
If the floating roof supports are changed from operating position to maintenance position, the lift has to be extended as well. This is done with an adjustable locking pin that is secured with a split pin. The valve is not flame transmission proof. Based on a hazard analysis with regard to material selection and function, the valves have no potential ignition sources. As a result, they are not subject to the European Explosion Explosion Plötzliche Oxidations- oder Zerfallsreaktion mit Anstieg der Temperatur, des Druckes oder beider gleichzeitig. Protection Directive (ATEX) when used in explosive atmospheres.
Maßtabelle für AL-DK und AL-DK-4
| AL-DK | AL-DK-4 | |||||||
| DN1 | 200 / 8" | 200 / 8" | 200 / 8" | 200 / 8" | 250 / 10" | 250 / 10" | 200 / 8" | 200 / 8" |
| DN2 | 80 /3" | 100 /4" | 150 / 6" | 200 / 8" | 150 / 6" | 200 / 8" | 100 /4" | 200 / 8" |
| a | 350 / 13.78 | 350 / 13.78 | 350 / 13.78 | 350 / 13.78 | 350 / 13.78 | 350 / 13.78 | 350 / 13.78 | 350 / 13.78 |
| b | 465 / 18.31 | 465 / 18.31 | 465 / 18.31 | 515 / 20.28 | 465 / 18.31 | 515 / 20.28 | 465 / 18.31 | 650 / 25.59 |
| c | 870 / 34.25 | 870 / 34.25 | 870 / 34.25 | 870 / 34.25 | 870 / 34.25 | 870 / 34.25 | 870 / 34.25 | 870 / 34.25 |
| d | 450 / 17.72 | 450 / 17.72 | 450 / 17.72 | 450 / 17.72 | 450 / 17.72 | 450 / 17.72 | 450 / 17.72 | 600 / 23.62 |
| e | 345 / 13.58 | 360 / 14.17 | 385 / 15.16 | 415 / 16.34 | 385 / 15.16 | 415 / 16.34 | 415 / 16.34 | 415 / 16.34 |
| f | 460 / 18.11 | 445 / 17.52 | 285 / 11.22 | 370 / 14.57 | 285 / 11.22 | 367 / 14.45 | 445 / 17.52 | 370 / 14.57 |
| x | 658 / 25.91 | 920 / 36.22 | ||||||
Dimensions in mm / inches
Material
| Housing | Steel |
| Valve guide | Stainless Steel |
| Gasket | FPM |
Special materials upon request
Flange connection type
| EN 1092-1; Form B1 | andere Anschlüsse auf Anfrage |
| ASME B16.5 CL 150 R.F. |
Other types upon request
Data Necessary for Specification
Stored product Tank diameter (m or ft)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)
Selection and Design
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® EB or PROTEGO® LH/AD have additionally to be taken into account according to the appropriate charts in the relevant data sheetsor operating instructions.Design Types and Specifications
Two designs are available:Flow Capacity Chart
The flow capacity charts have been determined with a calibrated and TÜV certified flow capacity test rig. Volume flow V in (m³/h) and CFH refer to the standard reference conditions of air ISO 6358 (20°C, 1bar). For conversion to other densities and temperatures refer to Sec. 1: “Technical Fundamentals”.
Application Examples for PROTEGO® AL-DK
Lift-actuated vent valves of type PROTEGO® AL-DK can be combined with vent caps type EB 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”.
