Variable Spring Support & Hanger
Variable spring supports and rigid hangers for ductwork and pipework, selected from a standard range and supplied with the load and travel marked on the housing.
Key facts
- Model
- BZ-SH
- Load range
- 200 kg to 20,000 kg per unit
- Types
- Variable spring, constant effort, rigid rod, sliding support
- Load variation
- ≤ 25 % across travel for variable springs
- Travel
- 0 to 200 mm by size
- Finish
- Hot dip galvanised, or epoxy system for coastal duty
- Standard series from 200 kg to 20,000 kg
- Cold and hot load stamped on every unit
- Pinned in the cold position before despatch
- Hot dip galvanised for outdoor ductwork
Description
A duct that expands by 40 mm between cold and hot will lift its own supports off the steel if those supports are rigid. Spring hangers take up that movement while carrying the weight, and a variable spring does it without the load changing more than 25 % across the travel.
Range
We supply the standard variable spring series from 200 kg to 20,000 kg per unit, in single and double arrangements, plus rigid rods, sliding supports and constant-effort units for the small number of positions where even 25 % load variation is too much. Selection is made from the calculated load and the actual travel at the support point, not from the duct size.
What is marked on the housing
Every unit leaves the works with the cold load, the hot load, the travel and the direction of travel stamped on a stainless plate. That plate is the only reliable way to set the support on site, and its absence is the most common reason a spring ends up preset to the wrong figure.
Corrosion protection
Housings are hot dip galvanised as standard for outdoor ductwork. For coastal or FGD areas we offer a zinc-rich primer plus two coats of epoxy, and stainless springs where the environment justifies it. Springs are never painted: paint on a coil changes the rate.
Setting on site
Supports are pinned in the cold position at the works. The pin is removed only after the duct is fully erected and the insulation is on, and only by someone who has read the load plate. We supply a setting sheet with each consignment listing every tag, its cold setting and its hot setting.
Typical applications
- Flue and air ductwork on boiler structures
- Steam and hot water pipework
- FGD absorber and duct supports
- Any run with significant thermal movement
Get a price for this damper
Send the duct section, design temperature, pressure difference and quantity. We answer within one working day.
Request a quotation
Tell us the duct section, design temperature and pressure difference. We will come back with a general arrangement drawing and a price.