ProFlapII and ProFlapPlusII Back pressure flap ProFlapII and ProFlapPlusII for explosion decoupling The Task The Solution

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Kathryn Hill
6 years ago
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ProFlapII and ProFlapPlusII Back pressure flap ProFlapII and ProFlapPlusII for explosion decoupling The Task Numerous processes can create explosive dust/air mixtures inside industrial systems (eg.

If ignition sources cannot be prevented due to process conditions, these systems are often equipped with constructive explosion preventive measures such as pressure relief or pressure suppression.

1 ProFlapII and ProFlapPlusII Back pressure flap ProFlapII and ProFlapPlusII for explosion decoupling The Task Numerous processes can create explosive dust/air mixtures inside industrial systems (eg., dust collectors, mixing machines, fluid bed granulator, mills, etc.). If ignition sources cannot be prevented due to process conditions, these systems are often equipped with constructive explosion preventive measures such as pressure relief or pressure suppression. In this regard, connected ductworks are decoupled from containers to be protected so that no flames and explosion pressure can be transferred into other areas. Sample application of an exhaust system that is equipped with explosion pressure relief: mounting distance fan capturing back pressure flap separator explosion pressure relief The Solution Keller Lufttechnik developed the back pressure flap series ProFlap for an effective explosion decoupling for nearly all industrial sectors. The ProFlap is certified as a protective system according to EU Guideline 94/9/EG (ATEX 95) and is approved for decoupling of dust explosions of organic and mineral dusts. ProFlapPlusII

Operation Normal operation During operation, the downstream mounted back pressure flap is kept open by means of the air flow. When fully stopped, the flap closes by its own weight.

During an explosion inside a protected system, the flap is closed by the pressure surge inside the ductwork. The explosion flame and the pressure cannot strike back the ductwork.

The flap damping element prevents the flap from opening following an explosion because of decreased pressure.

2 Operation Normal operation During operation, the downstream mounted back pressure flap is kept open by means of the air flow. When fully stopped, the flap closes by its own weight. When the system starts up, the opening of the flap is restrained by a damping element The downstream mounted back pressure flap is kept open by means of the air flow In the event of an explosion During an explosion inside a protected system, the flap is closed by the pressure surge inside the ductwork. The explosion flame and the pressure cannot strike back the ductwork. Personnel working at capturing points or downstream system parts are protected against the explosion effects. The flap damping element prevents the flap from opening following an explosion because of decreased pressure. On an explosion within a protected system the flap closes due to the pressure front spreading within the ductwork Monitoring function of ProFlapPlus (optional) To increase inspection intervals, the optional monitoring device ProFlapPlus is available (patented). An integrated wear sensor and a sensor to monitor the flap position control the wear of the flap and the closing operation. The sensors are completely wired inside a control cabinet which is mounted at the return valve. An analysis of the signals is carried out at the electrical cabinet which is provided by the customer. Alternatively, it is possible to purchase a separate electrical cabinet (see accessories ). Wear sensor Accumulation sensor ProFlapPlusII 2

Scope of applications downstream explosion decoupling of dry dust separators when grinding fiberglass reinforced components for chemical and pharmaceutical industries for timber industry for varnish

Applications also possible for dust concentrations exceeding the lower explosion limits.

3 Scope of applications downstream explosion decoupling of dry dust separators when grinding fiberglass reinforced components for chemical and pharmaceutical industries for timber industry for varnish dusts etc. for blasting plants Explosion decoupling for dryers, air separators, mills, silos, fluid bed granulators, etc. Applications also possible for dust concentrations exceeding the lower explosion limits. Advantages certified according to the latest test standard CEN/TC 305/WG 3 N457 (Stand: 05/2012) applicable for organic and mineral dusts passive system, no triggering sensors required inexpensive in comparison to other decoupling systems modular monitoring package for system control and greater inspection intervals easy access using fasteners, without loose components ease of access for inspection with swiveling flap integrated consoles for easy assembly variable mounting distances (for suction ducts, the referenced distances are minimum dimensions) application feasible for dust concentrations beyond the lower explosion limits (specified distances must be strictly adhered to) Simulation systems When developing the monitoring sensors, up-to-date air flow simulation systems were used in order to determine ideal positioning of the sensors. directly advancing flow flow advancing from below advancing flow from above laterally advancing flow CFD Proflap NS315 simulation parameters: velocity of oncoming flow : 20 m/s particle mass flow (silica): 5,7 g/s particle size distibution (silica): 10µm up to 500µm Effect of impacting particles on sheet metal (indication of abrasion): blue: no abrasion red: increased abrasion 3

4 Sizes, technical data Type Nominal width Length L Width B Height H Height S Weight Pressure loss on 20 m/s Max. opening angle of the flap NW mm mm mm mm kg Pa ProFlapII_ ProFlapII_ approx ProFlapII_ approx ProFlapII_ ProFlapII_ ProFlapII_ ProFlapII_ ProFlapII_ ProFlapII_ ProFlapII_ ProFlapII_ approx ProFlapII_ approx ProFlapII_ approx ProFlapII_ approx ProFlapII_ approx ProFlapII_ approx Mounting position: horizontal, on the suction side (fan behind ProFlapII) Air flow velocity: m/s Temperatures: -10 to + 60 C Materials: housing: S235JRG2, flap: stainless steel Paint finish: RAL 3000 blazing red Scale drawing ProFlapII 4

5 Possible dust explosion category Max. K ST - value Max. reduced excess pressure (pred, max) in the con - tainer filter)* Pressure surge resistance of back pressure flap Min. installation distance at St1 Min. installation distance at St2 Max. installation distance at St1 Max. installation distance at St2 bar x m/s bar bar m m m m St1 and St ,7 1,5 2,6 3,6 6,6 7 Subject to modifications. * The ductwork between ProFlapII and explosion protected housing/filter shall have the same max. reduced Pred, max (normally at least 2 mm sheet thickness, welded). 5

Guidelines and Standards Back pressure flaps are subject to a design check according to EU Guideline 94/9/EC (ATEX 95), latest

6 Accessories and guidelines Accessories A separate electrical control cabinet is available with integrated switch amplifier for the wear sensor. Guidelines and Standards Back pressure flaps are subject to a design check according to EU Guideline 94/9/EC (ATEX 95), latest standard applicable. Quality assurance is audited according to 94/9/EC (ATEX 95) and is regularly controlled. It is therefore permissible to return the back pressure flaps into circulation as independent protection systems. Reference installations examples 6

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ProFlapII and ProFlapPlusII Keller USA, Inc.

Explosion decoupling inside connected ductwork to protect separators

Back pressure flap ProFlapII Explosion decoupling inside connected ductwork to protect separators ProFlap back pressure flap prevents the spread of explosive pressure and explosion flame to other areas.