Choosing the right blower for a pneumatic conveying system is not simply a matter of finding the highest CFM or the largest motor. The blower must deliver the required airflow and pressure while remaining compatible with the material, conveying distance, pipeline, operating conditions, and existing equipment.
When buying used equipment, there is another layer to consider: the machine’s actual condition and service history.
Two blowers may have similar horsepower and capacity ratings but differ significantly in previous application, wear, maintenance, and remaining service life. A blower that was previously used for a demanding abrasive application, for example, may require a very different evaluation from one that handled a cleaner, less demanding process.
This guide explains how to choose the right used blower for pneumatic conveying, starting with the conveying requirements and moving through blower type, CFM, pressure, sizing, inspection, compatibility, ownership cost, and supplier evaluation.
Whether you’re purchasing a used blower for pneumatic conveying or another industrial application, selecting the right unit requires more than comparing prices. Understanding system requirements and equipment condition helps ensure long-term performance and reliability.
What Does a Blower Do in a Pneumatic Conveying System?
A blower provides the airflow and pressure difference required to move dry bulk material through a conveying pipeline. Depending on the system design, the blower may push air into the conveying line or create suction that draws material through the system.
The important point is that the blower does not operate independently. Its performance must match the entire conveying system.
The required airflow depends on factors such as:
- Material being conveyed
- Required conveying velocity
- Pipeline diameter and length
- Number of bends and fittings
- Elevation changes
- Material loading
- Filters and separators
- Conveying phase
- Required operating pressure
For example, a blower moving plastic pellets through a relatively short pipeline may have very different requirements from one conveying a dense mineral powder over a longer distance.
This is why choosing a blower based only on horsepower can lead to an unsuitable machine. Horsepower indicates motor capacity; it does not, by itself, tell you whether the blower will provide the required airflow and pressure at your operating point.
JM Industrial’s current inventory illustrates this range: its blower category includes positive displacement, single-stage centrifugal, multi-stage centrifugal, regenerative, and other blower configurations with different performance characteristics.
What Type of Blower Is Used for Pneumatic Conveying?
The appropriate blower type depends on the required airflow, pressure, conveying method, and application. Common industrial options include positive displacement blowers, centrifugal blowers, and regenerative blowers.
Positive Displacement Blowers
Rotary positive displacement, or rotary lobe, blowers trap and move a relatively fixed volume of air with each revolution. They are widely used where a steady airflow is required against changing system pressure.
They are commonly considered for pneumatic conveying applications requiring relatively high pressure and consistent airflow. JM Industrial stocks used positive displacement and rotary lobe blowers from manufacturers including Gardner Denver, Dresser, and Howden Roots.
Centrifugal Blowers
Centrifugal blowers use a rotating impeller to accelerate air and convert velocity into pressure. They can be suitable for applications requiring higher airflow, depending on the pressure requirement and system design.
Single-stage and multi-stage centrifugal blowers are available for different operating ranges. JM Industrial’s inventory includes both configurations with documented CFM and static-pressure specifications on individual units.
Regenerative Blowers
Regenerative, or side-channel, blowers are generally used for high-volume, lower-pressure airflow and can be used in applications including pneumatic conveying, aeration, and vacuum service.
| Blower Type | General Characteristic | Typical Selection Consideration |
|---|---|---|
| Positive Displacement | Steady airflow against pressure | Pneumatic conveying and pressure applications |
| Centrifugal | High airflow potential | Higher-volume airflow requirements |
| Regenerative | High volume, lower pressure | Lower-pressure conveying or vacuum applications |
The table is a starting point, not a substitute for system calculations. A blower should be selected from its performance curve at the required operating point.
Key Takeaway: Don’t select a blower type simply because it is commonly used. Match its operating characteristics to the actual conveying system.
How Do CFM and Pressure Determine Blower Selection?
CFM tells you how much air the blower moves, while pressure indicates how much resistance the blower can overcome. Both values must be considered together.
CFM, or cubic feet per minute, represents airflow volume. In pneumatic conveying, sufficient airflow is necessary to maintain the velocity required to transport the material through the pipeline.
Pressure is commonly expressed as inches of water column (in. H₂O) or PSI, depending on the application and equipment specifications.
A blower rated for 1,000 CFM is not automatically suitable for a system requiring 1,000 CFM. You also need to know at what pressure that airflow is delivered.
For example, a blower might provide a certain CFM at a relatively low pressure but deliver less airflow as system resistance increases. The correct operating point must therefore be checked against the blower’s performance curve.
CFM vs. Pressure: What Matters?
- CFM: Determines the volume of conveying air.
- Pressure: Determines the blower’s ability to overcome system resistance.
- Operating point: The combination of airflow and pressure at which the blower actually operates.
This distinction is particularly important when purchasing used blowers because the nameplate may show motor horsepower or maximum pressure without giving you the complete performance information required for your system.
Ask for the blower’s performance data whenever available, and compare it with your system’s required airflow and pressure.
How Do You Determine the Required Blower Size?
Blower sizing starts with the conveying system, not the available used equipment.
The basic selection process is:
Determine material → establish conveying phase → calculate airflow → determine pressure requirement → check blower performance curve → verify motor and system compatibility.
The conveying line’s diameter and length are particularly important. A longer line generally creates more resistance than a shorter line, while additional elbows, valves, filters, and separators add pressure losses.
Material properties also influence the required conveying conditions. Bulk density, particle size, particle shape, moisture, and abrasiveness can all affect the appropriate conveying velocity and system design.
A system conveying lightweight plastic pellets may therefore require a different operating point from one moving dense mineral powder.
Dilute-Phase vs. Dense-Phase Conveying
Dilute-phase conveying generally transports material at higher conveying velocities and lower solids concentration.
Dense-phase conveying uses a higher solids-to-air ratio and generally operates at higher pressure with lower material velocity.
Because these systems operate differently, the blower requirements can differ substantially.
For a used blower purchase, don’t assume that a machine previously used for one conveying configuration will automatically suit another. Verify the actual CFM, pressure, material, and operating conditions.
Key Takeaway: Blower size should come from the required system operating point not simply from motor horsepower, physical size, or the largest machine available.
How Does the Material Affect Blower Selection?
The material being conveyed is one of the most important variables in pneumatic conveying design.
Consider:
- Bulk density: Heavier materials may require different conveying conditions.
- Particle size: Fine powders and larger pellets behave differently in air.
- Abrasiveness: Abrasive materials can accelerate wear in conveying components.
- Moisture: Moist or cohesive materials may require different conveying approaches.
- Fragility: Brittle products may require lower conveying velocities to minimize degradation.
- Temperature: Hot materials can affect equipment and seals.
The material also influences the risk involved when purchasing a used blower.
Suppose a used positive displacement blower previously handled a relatively clean product, while another identical unit operated in a highly abrasive application. Their external appearance may be similar, but the second machine deserves closer attention to internal clearances, rotors, bearings, seals, and other wear-related components.
How Do You Choose the Right Used Blower?
Once you’ve established the required blower type, CFM, pressure, and operating conditions, you can evaluate available used equipment.
Start with the machine’s identity and history.
Verify:
- Manufacturer and model
- Serial number
- Rated CFM
- Pressure or vacuum rating
- RPM
- Motor horsepower
- Motor voltage
- Inlet and outlet size
- Previous application
- Operating hours, if available
- Maintenance history
- Previous repairs
- Storage conditions
Don’t assume that a lower-hour machine is automatically the better purchase. Operating environment and maintenance practices can be just as important as hours.
A blower used intermittently in a clean application may have experienced less wear than one operated continuously in a demanding environment.
This is where detailed equipment documentation becomes particularly valuable. JM Industrial states that, when available, its listings provide specifications, nameplate data, manufacturer information, and photographs to help buyers evaluate equipment before purchase.
What Should You Inspect Before Buying a Used Blower?
A used blower should be inspected for mechanical wear, structural condition, lubrication issues, and compatibility with the intended application.
Inspect the Blower Assembly
Check the housing, rotors or impeller, shafts, seals, and connections for signs of damage, corrosion, or abnormal wear.
Check Bearings and Drive Components
Listen for unusual noise and check for excessive play, vibration, overheating, or evidence of poor lubrication. Inspect couplings, belts, pulleys, and timing components where applicable.
Examine Positive Displacement Blowers Carefully
For rotary lobe blowers, internal clearances are important. Excessive wear can affect performance and efficiency. Timing gear condition and rotor condition should also be evaluated.
Inspect Centrifugal Blowers
For centrifugal equipment, inspect the impeller, shaft, bearings, housing, and inlet/outlet connections. Check for evidence of imbalance or previous repairs.
Don’t Ignore the Motor
Confirm:
- Voltage
- Phase
- Frequency
- Horsepower
- RPM
- Frame size
- Enclosure type
A blower can be mechanically suitable but still require costly electrical modifications if the motor does not match your facility.
If an in-person inspection isn’t practical, request detailed photographs, nameplate information, available inspection data, and an operating video where possible.
Check Used Blower Compatibility With Your Existing System
A blower can meet your CFM and pressure requirements and still be unsuitable for your plant if it doesn’t physically or electrically integrate with the existing system.
Before purchasing, verify:
- Inlet and outlet connections
- Pipe diameter
- Connection orientation
- Motor voltage and phase
- Available power
- Footprint
- Mounting arrangement
- Controls
- Available installation space
- Required accessories
Also check whether the existing pipeline and filtration system can accommodate the selected operating conditions.
This is particularly important when purchasing a complete used blower package. For example, JM Industrial has listed used pneumatic conveying blower packages that include the blower, motor, and specified connection information, allowing buyers to evaluate more of the package against their installation requirements.
How Much Should You Spend on a Used Blower?
The purchase price is only one part of the investment.
Calculate the expected total cost by considering:
- Equipment purchase price
- Freight
- Rigging
- Installation
- Electrical work
- Piping modifications
- Immediate repairs
- Replacement parts
- Commissioning
- Energy consumption
- Preventive maintenance
A blower that costs less initially may require significant refurbishment before startup. Conversely, a higher-priced machine with good documentation, suitable condition, and recent maintenance may require less additional investment.
Compare the total cost to become operational, not simply the equipment price.
This is also where used equipment can provide an advantage. JM Industrial describes its used and surplus blower inventory as a cost-effective alternative and offers equipment across several blower technologies and specifications.
Why Does the Supplier Matter When Buying a Used Blower?
The supplier can significantly affect the amount of information available before purchase.
A reliable used equipment supplier should be able to provide as much relevant information as is available, including equipment specifications, nameplate data, photographs, condition information, and inspection support.
For higher-value equipment, buyers may also want to ask about:
- Independent inspection
- Operational testing
- Available service records
- Shipping and loading
- Spare parts
- Equipment documentation
- Technical questions before purchase
That type of supplier transparency is particularly useful when comparing used equipment remotely, because buyers can evaluate available technical information before arranging transportation or installation.
Used Blower Buying Checklist
Before finalizing your purchase, verify the following:
- Required CFM confirmed
- Required pressure confirmed
- Blower type is appropriate
- Material characteristics considered
- Conveying phase identified
- Manufacturer and model verified
- Motor specifications confirmed
This checklist can also be used when comparing several used blowers for sale to ensure each machine is evaluated using the same criteria.
Conclusion
Choosing the right used blower for pneumatic conveying requires two separate but connected decisions: first determine what your conveying system needs, then identify a used blower that can reliably meet those requirements.
Start with airflow, pressure, conveying phase, material characteristics, pipeline configuration, and operating conditions. Once those requirements are established, evaluate available blowers based on their type, specifications, operating history, maintenance records, physical condition, motor configuration, and system compatibility.
Don’t make the final decision on purchase price alone. A blower that appears inexpensive may require substantial refurbishment or modifications, while a properly documented and well-maintained machine may provide better overall value.
Working with an experienced supplier can also simplify the process. JM Industrial offers used and surplus blowers across multiple configurations, including positive displacement, centrifugal, and regenerative blowers, with equipment information and technical support available to help buyers evaluate their options.
Ultimately, the right used blower is not simply the one with the highest CFM or lowest price. It is the machine that matches the conveying system’s required operating point and can deliver dependable performance within your installation and maintenance requirements.
Frequently Asked Questions (FAQ’s)
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Why is a blower running hotter than it normally does even though the operating speed has not changed?
An unexpected temperature increase can result from higher discharge pressure, restricted airflow, excessive loading, lubrication problems, bearing deterioration, or internal mechanical issues. If system conditions have remained unchanged, the temperature increase should be investigated rather than treated as normal operation.
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Why has blower vibration increased gradually instead of appearing suddenly?
Gradually increasing vibration can indicate developing bearing wear, coupling or alignment problems, timing gear deterioration, rotor imbalance, or other mechanical changes. Tracking vibration trends can help identify developing deterioration before a more serious failure occurs.
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Why is a pneumatic conveying system losing capacity even though the blower is running?
The blower may no longer be delivering its expected airflow or pressure, or system resistance may have increased. Internal wear, increased clearances, inlet restrictions, pipeline changes, and filtration problems can all contribute to reduced conveying capacity.
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Why is blower airflow decreasing even though RPM and motor operation appear normal?
Reduced airflow at the same speed can indicate increased internal clearances, leakage, inlet restrictions, or changes in system resistance. Comparing current airflow and pressure with historical or manufacturer performance data can help isolate the cause.
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What should I check before buying a used blower for pneumatic conveying?
Verify the required CFM and pressure first, then check the blower’s previous application, operating condition, maintenance history, motor specifications, connections, and available documentation. The used unit should be evaluated against the requirements of the actual conveying system rather than selected by horsepower or price alone.
