side & door ventilation systems
XL's side vent system uses a gearbox assembly which is operated by an endless chain. It is very easy to operate and takes much less effort than the tradtional cranked handle.
Can be retrofitted to any straight sided tunnel or greenhouse. A clutch inside the gearbox holds the central torsion bar steady at any postion you choose between fully open and fully closed. It runs up a guide rail (see photo) which holds it in place.
The torsion bar shown in the picture is 3.5m long galvanised steel, swaged at one end so that you can create a continuous bar. You can join it together with a self drilling screw which we supply free with every bar. You use the same tube at the bottom as a weight bar at the bottom of the side vent poly. Maximum recommended length (with 25mm tube) is 35 metres.
The clips are a spring plastic with rounded edges so that they don't damage the polythene, we recommend you clip every 20cms.
The side vent can either be held in place with our PolyVent netting or retaining tubes which run from gutter to the ground as shown the bottom photo.