Description

Product Overview

A manual air damper valve is an injection-moulded polypropylene or PVC damper fitted into a PP duct run. The opening is adjusted by hand at the valve, giving local control of airflow volume without an actuator or control signal, and the valve matches the round PP duct range from φ63mm to φ500mm.

The valve is injection moulded in PP or PVC, in beige or grey, and joins the duct run by hot air welding, with socket connection reinforcement at the joint. Standard sizes cover φ63mm to φ500mm, and custom sizes are made to order. For the straight duct this damper is fitted into, see Polypropylene Round Ducts.

A manual damper valve is one part of a ventilation system: it regulates airflow volume in the run rather than connecting or branching it, and matching fittings are available from the same supplier so a complete PP duct line can be specified from one source.

Product Selection Summary

Good Fit

• Duct runs where airflow volume is set once and adjusted on site
• Branch lines that need local balancing without remote control
• Systems where manual access to the valve position is available
• Projects needing simple, reliable volume control without actuators

Conditions To Confirm

• Duct diameter (φ63mm to φ500mm, 12 standard sizes or custom) and quantity
• Material grade: PP or PVC
• Where the valve will sit in the run and how it will be reached for adjustment
• Gas composition, concentration, temperature and moisture at the operating point

Not a Replacement For

• Fans, airflow balancing devices, back draft dampers or gas treatment equipment

Technical Specifications

Confirmed Product Parameters

Parameter	Value
Product Type	Manual Air Damper Valve (volume damper for duct)
Material	PP (polypropylene) or PVC
Size Range	φ63-500mm – 12 standard sizes or Customized
Connection	Hot air weld; socket connection reinforcement
Fabrication	Injection molding
Color	Beige / Grey
Working Temperature	-15℃ to 80℃
Chemical Resistance	pH 1-14 (acid and alkali)
Certification	ISO9001, ISO14001, RoHS

Available Sizes (φ)

Diameter	Diameter
φ63mm	φ250mm
φ75mm	φ315mm
φ90mm	φ355mm
φ110mm	φ400mm
φ160mm	φ450mm
φ200mm	φ500mm

For sizes outside the standard range, custom valves are made to order – confirm the required diameter with the project.

Material & Performance

Because round fittings are injection moulded rather than welded from sheet, the damper keeps the same corrosion resistance as the welded duct while offering consistent moulded dimensions, smooth surfaces and a shorter production time for standard sizes.

Manual air damper valves are injection moulded from PP or PVC, both chosen for corrosive fume handling in ductwork:

• Acid and alkali resistance: the valve body withstands corrosion by acids and alkalis across a wide pH range (pH 1-14).
• Sound insulation: PP and PVC reduce vibration and noise transmitted through the fitting.
• Light weight: moulded fittings are light and easy to handle and weld on site.
• Consistent moulded dimensions: each size is produced to a standard mould, giving uniform dimensions and wall thickness across batches.
• Long service life: plastic duct systems offer a long service life under specified operating conditions; limits depend on the material grade selected.
• Anti-condensation: the material conducts heat poorly, reducing condensation and heat loss at the fitting.

Working temperature and service limits follow the material grade selected – PP or PVC – and are confirmed against the operating conditions when quoting. The material grade applies to the whole fitting, so a single grade can be specified across the duct, fittings and accessories in the run.

Applications

Manual Balancing

Manual damper valves are fitted where airflow volume is set and adjusted by hand:

• Branch balancing – trimming the volume of each branch to match the design
• Fan outlet control – adjusting flow at the fan discharge
• Terminal volume setting – setting the flow to a hood, hood filter or outlet
• Simple on-site adjustment – re-balancing a run when loads change

The valve is set by hand at the fitting: the opening is adjusted to the required position and left in place, so the volume stays at the set point until the run is re-balanced. With no actuator or control wiring, the manual damper is a simple, low-maintenance option for local flow control.

Selection Notes & Quotation Information

Manual or Electric Damper?

A manual air damper valve is adjusted by hand at the valve. An electric air damper valve is driven by an actuator, so it can be adjusted remotely, automatically or from a control system. Choose the manual version where a hand adjustment at the duct is sufficient; choose the electric version where the damper must respond to a controller.

Back Draft or Manual Damper?

A back draft damper is an automatic one-way valve that stops backflow but does not regulate volume. A manual damper valve regulates airflow volume by adjusting the opening. The two serve different functions and can both appear in one system.

To Quote Manual Air Damper Valve

Provide: duct diameter (φ63-500mm or custom), quantity, material grade (PP or PVC), color (beige or grey), application, destination port, and your duct schedule or drawings.

MOQ and lead time are confirmed per project. Request a quote via WhatsApp or email using the contact block below.

Installation & System Integration

Manual air damper valves are joined to the duct run by hot air welding, and the joint is reinforced with a socket connection. The valve is positioned where the opening can be reached for adjustment, then set to the required position after the run is installed. The same joining method applies to straight duct and other fittings, so the valve becomes part of one welded, sealed system.

Complete systems combine manual damper valves with straight duct, rain caps, elbows and couplings. See the full range of PP duct systems.

Related Products

• Polypropylene Round Ducts
• Electric Air Damper Valve
• PP Back Draft Damper
• PP Duct Rain Cap
• PP 90° Elbow
• Full PP Duct Range
• PP Air Duct Guide – a complete guide to PP duct types, sizes and materials.

FAQ

What is a manual air damper valve?

It is an injection-moulded PP or PVC damper fitted into a duct run – the opening is adjusted by hand at the valve, giving local control of airflow volume without an actuator.

How does it work?

The valve is set by hand at the fitting: the opening is adjusted to the required position and left in place, so the volume stays at the set point until the run is re-balanced.

What sizes are available?

12 standard sizes from φ63mm to φ500mm: φ63, φ75, φ90, φ110, φ160, φ200, φ250, φ315, φ355, φ400, φ450 and φ500mm – plus custom sizes made to order.

Manual or electric damper – which should I choose?

A manual air damper valve is adjusted by hand at the valve. An electric air damper valve is driven by an actuator for remote or automatic adjustment. Choose manual where hand adjustment is sufficient.

What material is it made from?

The valve is injection moulded in PP (polypropylene) or PVC, in beige or grey. Working temperature and service limits follow the material grade selected.

What do I need to provide for a quote?

Duct diameter, quantity, material grade (PP or PVC), color, application, destination port, and your duct schedule or drawings.