Envelope Filters
Envelope Filters are just that – they articulate the filter using an envelope. To do this, there is usually a knob dedicated to the filter frequency (cut-off point) just for the filter envelope. Turn the normal filter cut-off down, and turn the filter envelope cut-off higher, and then program the filter envelope like a normal envelope.
Takes a while to figure out, but its worth it – for example, turn the sustain on the filter envelope off, forget about the release and attack (set them to zero), and make the decay short – then turn up the release and wow! The thing to remember here is that its not the volume (amplitude) that your changing, it’s the cut-off frequency with the envelope, so you can create great effects with clever programming – such as emulating brass sounds by increasing the attack on the filter envelope.
Features
MODULAR SIZING
The size 50 - 1100 range of envelope filters is designed to cater for the most common dust problems, which usually involve a ducted system. Larger systems utilise a number of units in a modular form, or other types of filter from our range.
To cater for the wide range of air volumes encountered in ducted systems we can offer a variety of fan options. The units can be supplied without fans for multiple banking fan applications. Our engineers are at hand to select the correct fan for your particular requirement.
SPECIALIST FILTER MEDIA
The filtration of the air is achieved by passing it through cloth arranged in a multi-pocket, envelope form. Standard units are supplied with bags manufactured in cotton fabric, however, other media are available for greater efficiency. These include plain needle felt fabrics, felts with either surface treatments or membranes, or alternatively felts manufactured incorporating epitropic fibres to give antistatic properties.
AUTOMATIC FABRIC CLEANING
Each filter unit is supplied complete with an electro-mechanical shaking device which raps the filter element thoroughly following a delay after the main fan is switched off. This is all dealt with automatically by a control panel supplied free issue with each unit.
ENERGY EFFICIENT FANS
This range of fans from 0.7Kw up to 18.5Kw is designed to give high energy efficiency for the volume being handled, whilst still delivering sufficient external system pressure to cover most of the range of commonly encountered problems. The fan impellors are of a backward inclined, plate type and are mounted direct onto the motor shaft. These are mounted on top of the unit giving easy access for wiring and servicing, and in the event of fire ensures that the motor is outside the air-stream.
SIMPLE DUST DISPOSAL
The unit(s) are manufactured with a valley type hopper to channel the shaken dust into round collection bin(s). Each has a quick release system allowing easy removal after shaking down to allow the bins to be taken away for emptying at intervals.
ROBUST CONSTRUCTION
-The casings of all units are robustly constructed from heavy gauge sheet in welded panel form with stiffening where required. The unit door is of the quick release type to allow easy access.
MULTIPLE OPTIONS
Silencers are offered as an extra item if required for areas where noise must be kept to a minimum.
Flange mounting units are offered for silo mounting
-Explosion relief features, anti-spark fans, earthed filter elements, reinforced construction and blast relief doors are available for hazardous applications.
-Manometer(s) provide visual indication of the pressure drop across the filter(s)
-Secondary and absolute filters may be fitted where a higher degree of filtration than normal filters is required.
-Alternativer hopper discharges via flap or rotary valves.
-Units may be manufactured in alternative materials to suit special recommendations.
-After sales spares and/or maintenance contracts are available to ensure the equipment continues to work effectively in line with C.O.S.H.H. regulations.
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