Technical Range at a Glance

Blower Type Selection Matrix

Use this matrix to identify the right starting point for your enquiry. Your final blower type and size will be confirmed during technical discussion based on your actual process data.

For a duty point outside this table, share your process data with our engineers and we will recommend the appropriate type.

Materials of Construction (MOC) Centrifugal Blowers

Gas composition and temperature determine the correct material. AS Engineers fabricates blower impellers, housings, and internals in the following materials based on application:

• Mild Steel (MS) — Standard choice for clean air and general ventilation at ambient to moderate temperatures
• Carbon Steel (CS / SA516 Gr.70) — Pressure vessels and moderate-temperature process fans
• SS 304 / SS 304L — Food processing, general corrosion resistance, moderate chemical exposure
• SS 316 / SS 316L — Pharmaceutical applications (GMP-compliant with MTC and PMI documentation), acidic or chloride-present environments
• SS 321 — High-temperature stainless for oxidising gas streams
• Duplex SS 2205 — Highly corrosive environments, chloride stress corrosion risk
• SS 410 — Abrasive applications requiring hardened surfaces
• Hard Facing — Impeller blade leading edges for severe abrasion (fly ash, silica dust)
• Aluminium — Lightweight, spark-resistant applications

Material selection is always based on the specific gas handled, temperature, dust load, and corrosion potential – not a default.

How AS Engineers Designs a Centrifugal Blower

Most manufacturers select from a performance curve catalog. We begin at the process requirement and work backward to the impeller.

The design sequence for every custom blower is:

1. Duty point confirmation — Airflow (m³/hr or CFM), static pressure (mmWC or Pa), gas temperature, altitude, and gas density
2. Specific speed calculation — Determines the optimal impeller type for the given duty
3. Impeller geometry — Blade count, angle, width, and tip diameter calculated to meet the duty point at peak efficiency
4. Housing and scroll design — Volute proportions set for velocity recovery and minimum system effect
5. Drive arrangement — Belt-driven or direct-coupled, Arrangement 1/3/4/7/8/9 as required
6. Accessories — Expansion bellows, anti-vibration mounts, inlet damper, shaft seal, or cooling disc selected based on duty
7. Material selection — Based on gas analysis, temperature, and client specification
8. Performance testing — Every blower tested to IS 4894 before dispatch with airflow, pressure, and power readings recorded

This process applies whether the motor is 1 HP or 350 HP.

Industries and Applications

AS Engineers has supplied centrifugal blowers across 12 confirmed industries:

• Cement — Kiln induced draft fans, raw mill fans, cement mill ventilation, bag filter exhauster fans
• Chemical and Petrochemical — Reactor ventilation, corrosive gas exhaust, solvent vapour handling
• Fertiliser — Drying section air supply, dust collection, material handling conveyors
• Power Plants — Forced draft (FD) fans, induced draft (ID) fans, flue gas handling auxiliaries
• Pharmaceuticals — GMP-compliant process exhaust in SS 316L with MTC and PMI documentation
• Water Treatment and ETP — Aeration blowers for biological treatment tanks, sludge dryer support air systems
• Food and Beverages — Hygienic air supply and exhaust for drying sections, clean air applications
• Automotive — Paint booth ventilation, fume extraction, heat treatment furnace air supply
• Pulp and Paper — Stock preparation ventilation, drying section air systems
• Environmental and Pollution Control — Induced draft for scrubbers, bag filter exhauster fans
• Steel and Metals — Combustion air supply, furnace exhaust, cooling air
• Railways — Workshop exhaust and ventilation systems

Quality Assurance

Every centrifugal blower manufactured at AS Engineers goes through a documented inspection and testing sequence before despatch.

• Dimensional inspection against GA drawing
• Material test certificate (MTC) verification for critical components
• Impeller dynamic balancing to ISO 1940-1 Grade G6.3 (standard) or G2.5 (precision)
• Hydrostatic test on housing where specified
• Performance test to IS 4894 — airflow, static pressure, power consumption recorded
• PMI (positive material identification) for SS and alloy steel components where specified
• Noise level measurement where specified in the order
• Pre-despatch inspection by client or third-party inspector on request

Test reports are provided with every blower as part of standard documentation.

After-Sales Support

A centrifugal blower is a rotating machine. Performance can change over years of operation due to impeller wear, shaft misalignment, or bearing deterioration. AS Engineers offers the following services for blowers in service — including those not manufactured by us:

• Performance analysis — measure actual vs. design duty point
• Impeller repair and replacement
• On-site dynamic balancing
• On-site shaft alignment
• Bearing and seal replacement
• Retro-fitment for modified process conditions
• Annual maintenance contracts (AMC)
• OEM-quality spare parts supply

Frequently Asked Questions

What is the difference between a centrifugal blower and an axial fan?

A centrifugal blower moves air by spinning an impeller, which draws air in axially and discharges it radially at 90 degrees to the inlet. This generates significantly higher static pressure than an axial fan for the same shaft power. Axial fans move large volumes of air against low resistance and are suited for ventilation and cooling. Centrifugal blowers are the correct choice when static pressure requirements exceed approximately 50 mmWC or when the airstream contains dust, moisture, or corrosive gases.

Which centrifugal blower type is most energy efficient?

Backward curved blowers deliver the highest efficiency among centrifugal blower types for clean air applications. The airfoil or backward curved blade profile converts velocity energy to pressure more effectively than radial or forward curved designs. At a comparable duty point, backward curved impellers typically draw 10 to 20 percent less shaft power than forward curved designs. However, efficiency is always secondary to suitability: a radial blade blower in a dust-laden application will outlast a backward curved blower and reduce overall lifecycle cost despite slightly higher energy consumption.

What information do you need to size a centrifugal blower?

To accurately select and design a blower for your application, we need: airflow required (m³/hr or CFM), static pressure requirement (mmWC or Pa), gas temperature at the blower inlet, altitude of the installation site, nature of the gas handled (clean air, dust-laden, corrosive, humid), expected dust concentration (if any), preferred drive type (belt or direct), and any specific material or documentation requirements. If some of this data is unavailable, our engineers can assist with process calculations.

What is the delivery lead time for a custom centrifugal blower?

Lead time depends on motor power, size, and material of construction. Standard MS blowers in the range of 1 HP to 50 HP are typically ready in 3 to 5 weeks from order confirmation and GA drawing approval. Larger blowers, SS construction, or high-temperature configurations require 6 to 10 weeks. Exact lead time is confirmed at the time of order placement.

Do you supply centrifugal blowers with documentation for pharma or chemical projects?

Yes. For pharmaceutical applications requiring GMP compliance, we supply blowers fabricated in SS 316L with material test certificates (MTC), PMI reports, surface finish records, and weld inspection records. For chemical and EPC projects requiring IBR compliance or third-party inspection, we coordinate with approved inspection agencies. Documentation requirements should be specified at the enquiry stage.

Request a Quote for Your Centrifugal Blower

Share your process requirement – airflow, pressure, temperature, and application – and we will respond with a preliminary recommendation within one working day.

Submit your enquiry or call us at +91 99090 33851 / +91 82386 77554.

You can also explore our dedicated resources: highpressureblower.in for high pressure applications and idfan.in for induced draft fan requirements.