Pulp & Paper industry
The enviroment problem
"A paper mill does not just run wet. It runs wet, acidic, sulphurous, and hot simultaneously, continuously. Drive equipment that was not designed for that combination will not last. The motor that looks acceptable on paper will corrode in three months and fail in six."
Paper mills are among the most demanding environments for rotating drive equipment. Combining high-pressure steam, sulphurous Kraft process gases, chlorine from bleaching, abrasive fibre slurries, and permanent high humidity. Globe Airmotors supply pneumatic air motors with sealed stainless steel construction designed to keep running in exactly these conditions.
The pulp and paper industry creates a combination of environmental hazards that attacks drive equipment from multiple directions at once. The Kraft pulping process releases hydrogen sulphide (H2S) and other reduced sulphur compounds that corrode unprotected metal surfaces rapidly. Bleaching sequences using chlorine dioxide and hydrogen peroxide create strongly oxidising, corrosive atmospheres around the bleach plant. The paper machine itself operates in a permanent steam-laden, high-humidity environment and the press section is simply wet, all day, every day.
Globe Airmotors address the paper mill drive problem at the design level. Fully sealed construction prevents moisture and chemical ingress.
Applications
Where Globe air motors are specified in food & beverage
From stock preparation through to converting, these are the specific unit operations and equipment types where pneumatic air motors replace electric drives on auxiliary and secondary drive positions throughout the mill.
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Stock chest agitators: Continuous duty agitation of machine chest, blend chest, and broke chest contents. Fibre consistency variations cause sudden torque spikes that stall electric drives and trip thermal protection. Air motors stall cleanly without damage, restart automatically, and tolerate the high-humidity, fibre-laden atmosphere of the stock preparation area indefinitely.
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Pulper auxiliary drives: Secondary drives on drum pulpers and high-consistency pulpers handling recycled fibre, broke, and virgin pulp. Foreign material in recovered paper furnish — wire, staples, rope — causes frequent mechanical overloads. Air motors absorb these events without damage; the sealed construction tolerates the wet, aggressive environment of the pulping area.
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Chemical mixing & dilution: Agitator drives on chemical preparation tanks handling starch, sizing agents, retention aids, and wet-strength resins. Chemical additive tanks require continuous, consistent agitation — air motors provide this without the winding degradation that occurs when electric motors are exposed to chemical vapours in preparation areas adjacent to the paper machine.
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Bleaching tower auxiliary drives: Drive systems for wash press auxiliaries, dilution water systems, and stock transfer equipment in bleach plant sequences using ClO2, O2, and H2O2. The bleach plant is the most aggressively corrosive area of the mill — sealed stainless steel air motors tolerate chlorinated and oxidising atmospheres that rapidly degrade standard epoxy-coated electric motor enclosures.
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Chemical dosing pump drives: Metering pump drives for bleaching chemical addition — chlorine dioxide, hydrogen peroxide, sodium hydroxide, and bleach effluent treatment chemicals. Air-powered metering drives eliminate electrical components from the bleach plant's corrosive atmosphere and connect to the compressed air utility already distributed throughout the bleaching sequence.
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Bleach filtrate agitation: Agitator drives on bleach plant filtrate storage, effluent mixing tanks, and chemical recovery systems. Chlorine-bearing liquors and alkali extraction filtrates require continuous mixing — air motors in sealed stainless steel construction are the correct drive technology for vessels handling these highly corrosive process streams.
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Coating machine drives: Speed-controlled drives on coating colour agitators, colour kitchen mixing systems, and surface size applicator auxiliaries. Air motor speed regulation via inlet pressure provides smooth, stepless speed adjustment for coating operations where colour consistency depends on consistent agitation.
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Blade grinding & sharpening: High-speed air motor drives on doctor blade and slitter blade grinding systems. Compact Globe air motors at high speed deliver the grinding head performance required for blade maintenance operations.
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Reel & rewinder tension control: High-speed air motor drives on doctor blade and slitter blade grinding systems. Compact Globe air motors at high speed deliver the grinding head performance required for blade maintenance operations with no electronic speed control to protect from the water and paper dust environment of the paper machine area.
Pneumatic vs electric
Why sealed air motors outlast electric drives in the mill environment
The paper mill case for air motors is not primarily about safety certification or zone classification — it is about service life and maintenance cost in one of the most corrosive, humid, and mechanically demanding environments in manufacturing. These are the direct comparisons that drive the specification decision.
| GLOBE Airmotors - Pneumatic | Standard electric motor |
|---|---|
|
Fully sealed — no chemical or moisture ingress path | Enclosure seals degrade in continuous chemical atmosphere |
| Stainless Steel — resistant to H2S, chlorine, and acids | Mild steel / aluminium enclosure corrodes in Kraft and bleach environments |
| No windings — no moisture or chemical winding failure | Winding moisture ingress causes insulation breakdown over time |
| Overload stall — no thermal trip on agitator load spikes | Thermal trip on agitator overload requires manual reset |
| Self-cooling — no thermal derating in dryer section heat | Derated output in high-temperature dryer section areas |
| Speed control without electronics in humid environment | Variable speed drive requires protected enclosure in mill |
| Connects to existing mill compressed air utility | Additional cable routing and switchgear in wet areas |
| Lower long-term maintenance cost on auxiliary positions | Higher maintenance frequency on auxiliary drive positions |
GLOBE Airmotors food-grade range at a glance
| Continuous output range | Ingress protection rating | Material | Operating temperature range |
|---|---|---|---|
| 0.1 - 23 KW | IP64 | Stainless steel | -20 to +80 °C |
The Results
Why pneumatic
Built for the demands of paper mill environments
These are the engineering characteristics that make pneumatic air motors the practical specification choice for auxiliary drive equipment across pulp preparation, bleach plant, paper machine, and converting operations.
Fully sealed | Globe paper mill air motors have to be totally sealed. The exhaust air is internally managed and cannot carry mill atmosphere into the motor body, and external air cannot infiltrate from the surrounding environment. In a mill where H2S concentrations corrode copper windings within months and chlorine bleach plant atmospheres attack standard motor enclosures, the sealed construction of a pneumatic motor is not a specification preference. It is the reason the motor survives the environment. |
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Stainless steel housing | Globe motors for pulp and paper applications are available with stainless steel housing as standard. Stainless steel provides excellent resistance to the sulphurous, chlorinated, and acidic atmospheres found throughout a Kraft mill, without the degradation of epoxy coatings or the galvanic corrosion that occurs with dissimilar metals on mild steel enclosures in chemical atmospheres. The drive spindle is likewise produced from non-corrosive stainless steel. |
Overload-proof on agitators and pulpers | Stock chest agitators encounter sudden load spikes when fibrous consistency increases unexpectedly or foreign material enters the chest. Pulpers regularly contact obstructions — wire, rope, and reject material in recycled fibre furnish. Stall an air motor on a pulper or agitator and it stops drawing compressed air cleanly, draws no current, generates no heat, and restarts automatically when the obstruction clears. |
Steam and heat-resistant | Air motors are continuously cooled by the expansion of compressed air as they operate — the motor housing remains cool even at full continuous output. In the dryer section and around recovery boiler areas where ambient temperatures consistently exceed the thermal thresholds at which electric motors derate, a pneumatic motor maintains its full rated output without derating, forced cooling, or oversizing to compensate for thermal limitation. |
Speed control without electronics | Output speed and torque on a pneumatic motor are controlled by regulating air supply pressure and flow - no inverter drive, no control cabinet near the product zone, no electronics to protect during washdown. Simpler installation. Fewer failure modes. Lower total cost of maintenance over the machine's service life. |
Continuous duty, consistent output | Globe air motors are rated for continuous duty operation. On high-throughput filling, blending, and mixing applications where the line runs 18 or 20 hours per day, consistent torque output across the full shift - without derating for heat build-up - is a practical requirement, not a specification luxury. |
Compliance & standards
Engineered to meet pulp and paper making industry requirements
These are the six environmental conditions in a pulp and paper mill that determine motor selection. Each one alone is manageable. In combination, they are why standard drives fail early and why Globe sealed air motors are specified for auxiliary drive applications across the mill.
- Steam & permanent humidity: The paper machine drying section operates with steam cylinders at elevated pressure. Humidity throughout the mill approaches saturation in many areas. Globe motors are fully sealed; no air path connects the exterior atmosphere to internal components.
- H2S & sulphur compounds:The Kraft pulping process — the dominant pulping method globally — releases hydrogen sulphide, methyl mercaptan, dimethyl sulphide, and dimethyl disulphide as process by-products. These reduced sulphur compounds are strongly corrosive to copper windings, brass terminals, and unprotected mild steel surfaces — including motor enclosures not rated for chemical atmosphere exposure.
- Chlorine & bleaching chemicals: Bleach plant equipment operates in atmospheres containing chlorine gas (Cl2), chlorine dioxide (ClO2), and hydrogen peroxide (H2O2). Chlorine is among the most aggressive corrosives in industrial use, attacking mild steel, aluminium, and standard epoxy motor coatings rapidly. Bleach plant auxiliary drives specified in standard industrial motors require frequent replacement or costly protective enclosures.
- Abrasive fibre slurry: ulp stock in preparation areas is an abrasive, fibrous slurry with consistency levels ranging from 1% in dilute stock chests to 12–15% in high-consistency towers. Drive equipment on agitators and pulpers in contact with this slurry is subject to abrasive wear on seals and exposed shaft surfaces. Globe motors use sealed bearings and stainless steel output shafts resistant to fibre abrasion over extended service periods.
- High ambient temperature: The dryer section and recovery boiler area of a paper mill generate significant ambient heat. Electric motors derate in high-temperature environments output falls as ambient temperature rises above the rated thermal limit. Pneumatic air motors are continuously cooled by expanding air as they operate, running cooler under load than at rest, with no output derating in high-temperature mill environments.
- Continuous water ingress: The press section, couch roll area, and wet end of the paper machine operate with continuous water. White water carrying suspended fibres, fillers, and chemical additives. Drives installed in or near these areas are subject to continuous water spray, splash, and flooding. IP-rated motors resist initial ingress; fully sealed air motors with no air-breathing path tolerate sustained immersion conditions.
