REDDY COMPRESSORS
Cool the air. condense the water. separate the liquid. drain it reliably
Compression raises air temperature. As compressed air is subsequently cooled, its ability to retain water vapour changes and liquid can condense. That liquid must be separated and removed before it is carried into receivers, dryers, filters, piping and the process.
It does not replace a dryer where a defined pressure dew point is required. Aftercooling and bulk-liquid separation reduce the moisture burden; downstream drying controls remaining water vapour.
1 — Why Compression Creates a Moisture Problem
Atmospheric intake air contains water vapour. Compression and subsequent cooling can create condensate. Actual quantity depends on inlet humidity, temperature, pressure, flow and cooling.
2 — Aftercooling Is Heat Rejection
Aftercooler outlet condition depends on design, cooling medium, inlet temperature, ambient/cooling-water conditions, fouling and load.
3 — Air-Cooled Aftercoolers
Require adequate cooling airflow and protection from hot-air recirculation. Fouling, blocked airflow and high ambient can reduce performance.
4 — Water-Cooled Aftercoolers
Require suitable cooling-water flow, temperature and quality. Fouling, scale, corrosion and restriction can affect performance.
5 — Approach Temperature Must Be Defined
Use equipment-specific performance under stated conditions rather than a universal degrees-above-ambient promise.
6 — Cooling Creates Liquid to Capture
Condensed liquid can become entrained in the air stream and requires downstream separation.
7 — Separator Technology and Flow Range
Centrifugal, cyclonic, demister and other arrangements depend on geometry, velocity, droplet behaviour and operating range; name alone does not establish efficiency.
8 — Low and High Flow Matter
Verify the separator operating envelope and pressure drop rather than selecting from nominal pipe size.
9 — Pressure Drop Must Stay Visible
Cooling/separation equipment adds resistance. Do not hide avoidable restriction by raising compressor pressure.
10 — Drainage Completes Separation
Separated liquid must leave the pressure system reliably. Blocked, isolated or unsuitable drains can allow re-entrainment/carryover.
11 — Manual Drains Need Human Control
Manual drains can suit controlled situations but are not automatic moisture management.
12 — Timed Solenoid Drains
Open on schedule regardless of level; poor settings can waste air or leave liquid behind.
13 — Level-Sensing Drains
Can discharge condensate with limited intentional air loss when correctly selected; review capacity, contamination tolerance, utilities and fault indication.
14 — Float Drains
Can provide automatic drainage in suitable applications; orientation, contamination, pressure and maintenance matter.
15 — Drain Capacity Must Match Condensate Duty
Select for liquid quantity, pressure, contamination and operating conditions—not thread size alone.
16 — Isolation and Strainers Create Failure Modes
Maintenance provisions help, but a closed isolation valve can make a healthy drain useless.
17 — Drain Discharge Needs a Controlled Destination
Manage pressure release, splashing, noise, hot liquid and contamination according to equipment/site requirements.
18 — Receiver Drains Are Part of the Chain
Receivers can collect additional condensate as air cools; include them in the moisture-management plan.
19 — Filters Can Collect Liquid
Coalescing and other filters may require drainage. Failed drains can increase carryover and pressure problems.
20 — Dryer Drains Must Be Registered
Refrigerated dryers commonly include separation/drainage. Include these points in maintenance and troubleshooting.
21 — Wet Receiver Architecture
An upstream receiver can add cooling/residence and liquid collection in some systems but also changes dryer loading and storage condition.
22 — Dry Receiver Architecture
A downstream receiver stores conditioned air and serves a different role from upstream bulk condensation.
23 — Piping Layout Influences Condensate
Low points, dead legs, slope, risers, drops and drains influence where liquid accumulates.
24 — Hot Compressor Rooms Reduce Cooling Effectiveness
Hot-air recirculation can raise aftercooler outlet temperature, leaving more vapour to condense later downstream.
25 — Seasonal Conditions Change Load
Hot/humid intake conditions can create a different moisture burden from cool/dry periods.
26 — Startup Can Behave Differently
Cold piping, idle receivers and changing temperatures can create transient condensation. Record operating state.
27 — Condensate Can Contain More Than Water
Depending on compressor, intake and process, condensate may contain oil and other contaminants.
28 — Oil-Water Separation Requires Actual Condensate Review
Lubricant type, emulsion behaviour, condensate volume and applicable disposal requirements can affect treatment choice.
29 — Condensate Management Is Environmental Control
Collection, treatment and disposal follow actual condensate characteristics and applicable requirements; no universal disposal route is prescribed.
30 — Measure Before Blaming the Dryer
Investigate aftercooler temperature, separator/drains, receiver, bypass, piping, dryer conditions and downstream condensation before diagnosing dryer failure.
31 — Temperature Is Diagnostic Evidence
Measure defined compressor discharge/aftercooler points where appropriate and compare with equipment-specific expectations.
32 — Differential Pressure Can Reveal Restriction
Pressure before/after equipment under known flow can help identify restriction and fouling.
33 — Drain Alarms Can Improve Reliability
Critical systems may benefit from fault indication or monitoring according to process consequence.
34 — Critical Moisture Control May Need Redundancy
Redundant drainage or treatment may be justified by consequence, but must be engineered rather than symbolic.
35 — Maintenance Includes Heat-Transfer Surfaces
Cooler cleanliness, fans/water side, separators, drains, valves and discharge lines affect performance.
36 — Commission the Complete Chain
Verify cooling, aftercooler condition, separator installation, drain operation, receiver/filter drains, discharge routing and relevant readings.
37 — Build a Moisture Map
Record temperatures, pressures, drains, observed liquid and dew point where applicable from source through distribution.
38 — Changes Reopen Assessment
Higher flow, humidity, ambient, altered cooling, new piping, pressure or compressor technology can change condensate duty.
39 — Aftercooling Does Not Replace Drying
Bulk liquid removal and vapour drying solve different parts of the moisture problem.
40 — Make Failure Visible
Use accessible drains, identifiable discharge lines, measurement points and clear maintenance responsibility.
41 — Moisture-Management Register
Control point | Record |
|---|---|
Compressor discharge | Flow, pressure, temperature, operating case |
Aftercooler | Type, cooling medium, inlet/outlet conditions, pressure loss |
Separator | Type, rated flow/pressure, performance basis |
Drain | Technology, capacity, pressure, alarm/inspection |
Receiver | Wet/dry location, drainage, responsibility |
Filters | Drain points and differential pressure |
Dryer | Internal separator/drain points and limits |
Distribution | Low points, drains, sensitive branches, observed water |
Condensate handling | Collection, treatment and disposal governance |
Monitoring | Temperature, pressure, drain alarms, dew point where applicable |
Maintenance | Task and applicable equipment instruction |
Revision | Date, configuration, reviewer |
42 — Diagnostic Sequence: Water Downstream
Step | Question |
|---|---|
1 | Where was liquid observed and under what state? |
2 | What are compressor/aftercooler conditions? |
3 | Is separator correctly installed and within flow range? |
4 | Are separator, receiver, filter and dryer drains operating? |
5 | Is a bypass open/leaking? |
6 | Is dryer within inlet-flow/temperature/pressure envelope? |
7 | Could downstream cooling create new condensation? |
8 | Are low points/dead legs retaining liquid? |
9 | Have humidity, ambient or demand changed? |
10 | What evidence confirms corrective action? |
43 — Technical Verification Gate
Gate | Pass requirement |
|---|---|
M1 | Environmental moisture case defined |
M2 | Aftercooler basis identified |
M3 | Cooling conditions reviewed |
M4 | Separator matches flow/pressure |
M5 | Pressure loss visible |
M6 | All liquid collection points drained |
M7 | Drain technology/capacity matches duty |
M8 | Discharge route controlled |
M9 | Receiver/filter/dryer drains registered |
M10 | Distribution condensation reviewed |
M11 | Condensate management addressed |
M12 | Monitoring points defined |
M13 | Maintenance integrated |
M14 | Commissioning verifies chain |
M15 | Aftercooling not misrepresented as drying |
M16 | Changes trigger reassessment |
45 — Frequently Asked Questions
Why does a compressor produce water?
Atmospheric air contains water vapour; compression and subsequent cooling can cause part of it to condense.
What does an aftercooler do?
It removes heat after compression, promoting condensation for downstream separation.
Does an aftercooler dry air completely?
No. A dryer may still be required for the specified pressure dew point.
Why use a separator?
Cooling can create entrained liquid droplets that should be removed before travelling downstream.
Which automatic drain is best?
No universal best type; selection depends on load, contamination, pressure, air-loss objectives, utilities and maintenance.
Why is water reaching the plant?
Possible causes include cooling/separation, failed drains, dryer condition, bypass leakage, receiver/piping drainage or downstream condensation.
Can a receiver collect water?
Yes. Additional cooling can create condensate, so receiver drainage belongs in the plan.
Is condensate safe to drain anywhere?
Do not assume so. Contaminants and applicable disposal requirements must be assessed.
Does hot weather increase moisture problems?
Hot/humid inlet conditions and higher cooling temperatures can materially change moisture load.
What should I send for review?
Flow/pressure, temperatures, ambient/cooling conditions, separator/drain details, receiver/dryer/filter arrangement, piping observations and location/timing of downstream water.
48 — Final CTA
DO NOT LET CONDENSATE BECOME A DOWNSTREAM PROBLEM.
COOL IT. SEPARATE IT. DRAIN IT. MONITOR IT. THEN DRY THE REMAINING VAPOUR TO THE PROCESS REQUIREMENT.
Secondary CTAs: Review Aftercooling • Review Water Separation • Review Automatic Drains • Review Dryer Requirement
Checkpoint Record
Future revisions require a new version identity.
V2 expands aftercooling, condensation, bulk-liquid separation, drainage, diagnostics, commissioning and lifecycle controls without deleting V1.
V2 STATUS: STAGING READY — TECHNICAL / EDITORIAL VERIFICATION GATED
V2.1 — Moisture Starts With Intake Air
Atmospheric air contains water vapour. The moisture entering the compressor varies with intake state and air mass flow. Compression raises pressure and temperature; subsequent cooling can create liquid when saturation conditions are reached. Moisture management is therefore a thermodynamic and system problem.
V2.2 — Compression Does Not Create Water From Nothing
The system is largely handling moisture that entered with intake air. Hot/humid conditions can create a very different condensate burden from cool/dry conditions. Record ambient state, flow, pressure and cooling conditions instead of relying on a universal condensate-rate rule.
V2.3 — Relative Humidity Is Not Moisture Content
Relative humidity describes proximity to saturation at the current temperature, not a direct mass-of-water value. Warm air can contain more vapour than cooler air at the same relative humidity. Condensate estimates require an appropriate psychrometric/moisture basis.
V2.4 — Aftercooling Is Controlled Heat Rejection
Aftercoolers remove heat after compression. As air cools, vapour can condense. Outlet condition depends on discharge temperature, cooler design, cooling medium, ambient/cooling-water condition, load, fouling and available airflow/water flow.
V2.5 — Air-Cooled Aftercoolers
Adequate cooling airflow and clean heat-transfer surfaces are essential. Hot-air recirculation, blocked louvers, fouled fins or failed fans can raise outlet temperature and shift condensation downstream toward the process.
V2.6 — Water-Cooled Aftercoolers
Performance depends on cooling-water temperature, flow, quality and heat-transfer condition. Scaling, fouling, corrosion or restricted flow can degrade cooling. Water treatment, isolation and maintenance belong in the design.
V2.7 — Approach Temperature Needs Its Exact Definition
Do not promise a universal number of degrees above ambient. Preserve the manufacturer's rating definition and whether the reference is ambient air, entering cooling water or another condition.
V2.8 — Worked Moisture-Chain Scenario
Illustrative only: hot compressed air reaches the aftercooler, cooling condenses part of its water vapour, a separator removes bulk droplets, a drain discharges liquid, and remaining vapour reaches the dryer. Cooler, separator, drain and dryer therefore perform different functions.
V2.9 — Separator Function
After cooling, entrained droplets travel with the air. Separators use centrifugal/cyclonic, impingement, demisting or other mechanisms depending on design. The technology name alone does not establish efficiency.
V2.10 — Separator Performance Is Flow Dependent
Gas velocity influences droplet behaviour and pressure drop. Verify supported flow, pressure, temperature, performance basis and differential for the exact separator rather than selecting by pipe connection alone.
V2.11 — Pressure Drop Across Cooling and Separation
Aftercoolers, separators and connecting passages consume pressure. Fouling or undersizing can become an energy penalty when source pressure is raised to compensate.
V2.12 — Drainage Completes Separation
Collected liquid must leave the pressure system. A blocked drain, closed isolation valve, failed actuator or restricted discharge can cause accumulation and re-entrainment. Drain condition is part of moisture-treatment performance.
V2.13 — Manual Drainage
Manual drains can be appropriate in controlled applications, but depend on inspection and human action. Where continuous production or consequence demands automatic removal, a manual valve alone may not provide sufficient reliability.
V2.14 — Timed Solenoid Drains
Timed drains open on schedule rather than liquid level. Excessive open time wastes compressed air; insufficient drainage leaves liquid behind. Settings should reflect actual condensate load and seasonal changes.
V2.15 — Level-Sensing Drains
Level-sensing drains can reduce intentional air loss when correctly selected. Verify capacity, contamination tolerance, pressure range, utilities and fault indication.
V2.16 — Mechanical Float Drains
Float drains can operate without electrical control in suitable duties. Orientation, contamination, pressure range, mechanical freedom and service access matter. No drain technology is universally best.
V2.17 — Drain Capacity Is an Engineering Quantity
Select drains for actual condensate rate, pressure, contamination and discharge conditions—not thread size. Confirm supported capacity and allowable discharge backpressure.
V2.18 — Drain Manifolds Can Create Problems
Combining pressurised drains into a small common line can create backpressure or cross-flow. Follow equipment installation requirements and provide appropriate collection/pressure-break arrangements.
V2.19 — Receiver Condensate
Air can cool further inside a receiver and form additional liquid. Wet receivers need reliable drainage and should appear in the same moisture-management register as separators and filters.
V2.20 — Filter and Dryer Condensate Points
Coalescing filters and refrigerated dryers can collect liquid. Include their drains in the moisture map. Checking only the main separator drain can miss downstream failures.
V2.21 — Wet Versus Dry Receiver Architecture
An upstream wet receiver can support cooling, liquid collection and storage; a downstream dry receiver stores conditioned air. The correct arrangement depends on demand dynamics, dryer type and quality requirements.
V2.22 — Distribution Cooling Can Create New Condensation
Air may cool further in downstream pipework. If its vapour condition permits, new liquid can form even when compressor-room separation works. This is why bulk separation and vapour drying are separate duties.
V2.23 — Piping Low Points and Dead Legs
Low points, dead legs, sagging hoses and unsuitable branches can retain liquid. Identify these locations during troubleshooting and integrate them into future distribution engineering.
V2.24 — Seasonal Worst Cases
A system that appears dry in cool weather can face much greater moisture load during hot/humid periods. Design and verification should consider relevant critical environmental cases.
V2.25 — Startup and Shutdown Behaviour
Cold piping and idle receivers can create transient condensation when warm air returns. Record whether water appears during startup, steady production, peaks or shutdown because the mechanism may differ.
V2.26 — Build a Moisture Map
Map temperature, pressure, drains, observed liquid and dew point where applicable from compressor discharge through cooler, separator, receiver, filters, dryer and distribution. This makes phase change and accumulation visible.
V2.27 — Worked Local-Water Diagnostic
Illustrative only: water appears at one remote machine while other users remain dry. Inspect branch cooling, low points, local filters/regulators and whether the branch differs from the main treatment path. A local symptom does not automatically prove central dryer failure.
V2.28 — Worked System-Wide Diagnostic
Illustrative only: several areas show liquid after hot weather. Check aftercooler outlet condition, separator/drains, receiver drains, dryer inlet conditions, dryer operation, bypass and dew point. A system-wide change suggests a common upstream condition or overload.
V2.29 — Temperature as Diagnostic Evidence
Measure defined compressor discharge and aftercooler outlet temperatures where appropriate. Rising outlet temperature can indicate fouling, fan/water-flow problems, high ambient or increased load.
V2.30 — Differential Pressure as Evidence
Track pressure across coolers/separators at known flow where measurement is available. Rising differential can indicate restriction. Interpret differential with flow because low flow can mask deterioration.
V2.31 — Drain Monitoring and Alarms
Critical systems can justify fault indication, high-level alarms or formal inspection. Monitoring level follows process consequence and drain technology.
V2.32 — Redundancy for Moisture-Critical Service
Where liquid carryover has serious consequences, consider engineered parallel separation, duplicate drainage or treatment failover. Two devices without isolation/control do not prove redundancy.
V2.33 — Condensate Discharge Safety
Drain outlets can release pressurised air, hot liquid and contamination. Route discharge to controlled collection and prevent unsafe spray, noise or aerosol according to equipment/site requirements.
V2.34 — Condensate Characteristics
Collected liquid can contain lubricant, corrosion products, dust or other contaminants. Oil-free architecture does not automatically make condensate suitable for unrestricted discharge.
V2.35 — Maintain Heat-Transfer Surfaces
Cooler performance depends on clean surfaces and functioning fans/water circuits. Maintenance includes fin/coil cleanliness, fan condition, water-side fouling, separator condition and drains according to exact equipment.
V2.36 — Maintain Drains
Verify isolation position, inlet passages, sensing/float mechanism, solenoid/actuator where applicable, discharge line and alarm. A drain can appear electrically healthy while its inlet or outlet is blocked.
V2.37 — Commission the Moisture Chain
Prove cooling, separation and drainage together. Record load, ambient/cooling condition, aftercooler outlet state, separator installation, drains, receiver/filter/dryer drains, discharge routing and relevant readings.
V2.38 — Acceptance Is More Than No Visible Water
Absence of visible liquid during a short test does not prove a pressure-dew-point requirement.
V2.39 — Temporary and Rental Compressor Moisture
Rental packages can deliver different temperature, moisture and oil carryover. Before connection, verify inlet conditions, flow, pressure and existing treatment capacity. Matching nominal CFM alone is insufficient.
V2.40 — Expansion and Changed Duty
Additional compressors, higher flow, hotter rooms or changed cooling water can increase condensate load. Recheck aftercooler, separator and drain capacity.
V2.41 — Energy Consequences
Fouled coolers/separators increase pressure loss; failed drains can waste air or overload treatment; poor aftercooling increases dryer load. Moisture management affects quality and lifecycle energy.
V2.42 — Failure Modes and Effects
Review fan failure, blocked cooler, insufficient cooling water, separator overload, drain failed closed/open, closed isolation, blocked discharge and receiver/filter drain failure. Define detection, consequence, response and repair verification for critical systems.
V2.43 — Evidence Hierarchy
Distinguish manufacturer performance, calibrated temperature/pressure measurements, drain tests, observed condensate, dew-point data and estimates. Visual evidence identifies symptoms but does not replace quantitative quality verification.
V2.44 — Common Engineering Mistakes
Avoid universal outlet-temperature or moisture-removal claims, separator selection by connection size, treating separators as dryers, ignoring drain backpressure, blaming the dryer before checking upstream moisture management and assuming condensate is clean water.
V2.46 — Premium Moisture-Management Register
Control point | Engineering record | Failure evidence |
|---|---|---|
Compressor discharge | Flow, pressure, temperature, load | Abnormal discharge condition |
Aftercooler | Cooling medium, inlet/outlet condition, differential | High outlet temperature / restriction |
Separator | Type, flow/pressure basis | Carryover / overload / pressure loss |
Drain | Type, capacity, pressure, discharge route | Failed closed/open / blocked line |
Wet receiver | Pressure, storage role, drain | Accumulated liquid |
Filters | Differential and drain points | Carryover / loaded element |
Dryer inlet | Flow, pressure, temperature | Overload condition |
Distribution | Low points, branch conditions | Downstream condensation |
Monitoring | Temperature, pressure, alarms, dew point | Trend deviation |
Condensate route | Collection/treatment interface | Uncontrolled discharge |
V2.47 — Water-Downstream Diagnostic Workflow
Step | Evidence question | Possible direction |
|---|---|---|
1 | Where and when is liquid observed? | Local vs system-wide mechanism |
2 | What are ambient/intake conditions? | Seasonal moisture loading |
3 | What is aftercooler outlet condition? | Cooling performance |
4 | Is separator within supported flow? | Bulk-liquid carryover |
5 | Are all drains functional/open? | Accumulation/re-entrainment |
6 | What are dryer inlet conditions? | Dryer overload |
7 | Is bypass controlled? | Untreated-air path |
8 | Could downstream cooling condense vapour? | Distribution condensation |
9 | Are low points/dead legs retaining water? | Local accumulation |
10 | What evidence proves repair? | Post-correction verification |
V2.48 — Technical Verification Gate
Relevant ambient/intake moisture case is defined.
Aftercooler performance basis and cooling conditions are known.
Separator is selected for actual flow, pressure and temperature.
Pressure drop is visible in the system budget.
Every liquid collection point has controlled drainage.
Drain technology/capacity match the duty and discharge routing is controlled.
Receiver, filter and dryer drains are included in the register.
Distribution condensation risks and low points are reviewed.
Temperature/differential-pressure diagnostic points are defined.
Maintenance and alarms reflect process consequence.
Commissioning proves cooling, separation and drainage together.
Aftercooling is not misrepresented as final vapour drying.
Expansion/temporary supply triggers reassessment.
Field guide
The seven stages of compressed-air treatment
Air leaving a compressor is compressed, but rarely clean. It carries heat, water vapour and condensate, oil aerosol and vapour, dust, rust and, in sensitive work, microorganisms. Compression concentrates these contaminants, and as the air cools the water condenses. Treatment is a layered defence: each stage removes one kind of contamination and prepares the air for the next.
Not every system needs all seven. The order and the number of stages follow the air quality the process requires.
| Stage | Job | Without it |
|---|---|---|
| 1. Aftercooler | Cuts air temperature to near the cooling medium and turns vapour into removable liquid. Air-cooled, water-cooled, built in or external. | More moisture downstream, heavier dryer load, condensation in receivers and pipes, corrosion |
| 2. Moisture separator | Removes bulk liquid by centrifugal action or impingement; condensate leaves through a drain (timed, float, level-sensing or zero-loss). | Water in pipelines, corroded valves and actuators, paint defects, freezing in cold sites |
| 3. Refrigerated dryer | Cools air in a refrigeration circuit, drains the condensate and reheats the air. Typical pressure dew point about +3 °C. | Wet air for general work; not enough for freezing pipes or very dry air |
| 4. Pre-filter | Coalescing filter takes liquid droplets, oil aerosol, rust and scale before the dryer. | Oil coats desiccant, dew point rises, desiccant and dryer fail early |
| 5. Adsorption dryer | Twin towers of alumina, silica gel or molecular sieve; one dries while the other regenerates. Typical dew points −20, −40 or −70 °C. | Air not dry enough for instruments, pharma, electronics, outdoor lines |
| 6. After-filter | Catches desiccant dust and fine particles leaving the dryer. | Dust reaching valves, cylinders, nozzles and product-contact points |
| 7. Point-of-use filter | Final protection at the process: particulate, coalescing, carbon, sterile, local separators, regulators. | Pipe rust, scale and condensate picked up in distribution reach the process |
Choosing an adsorption dryer
- Heatless uses a share of the dried air to regenerate. Simple and reliable, but it consumes purge air (see the purge worksheet).
- Heated purge adds a heater to cut the air needed for regeneration.
- Blower purge heats ambient air for regeneration and nearly removes compressed-air loss.
- Heat of compression uses the compressor's own heat and can be very efficient where the installation suits it.
Compare them on flow, pressure, inlet temperature and moisture load, required dew point, energy, regeneration method, duty cycle and ambient conditions.
Receivers and condensate
A wet receiver ahead of the dryer steadies pressure, adds condensate separation and cuts compressor cycling; a dry receiver after the dryer buffers demand. Every receiver needs a relief valve, gauge, drain, isolation valve, inspection access and certification. Condensate holds water, oil, solids and corrosion products, so it needs reliable automatic drains, drain monitoring and, for oil-lubricated machines, oil-water separation before disposal. One failed drain can defeat a well-designed train.
Specify by measurable class
“Clean”, “dry” and “oil-free” are not specifications. ISO 8573-1 classifies air by solid particles, water and total oil. A workshop, a pharmaceutical filling line, a paint booth and instrument air need different classes. The sequence is: find the most sensitive process, set the ISO 8573-1 class, set the pressure dew point, choose stages, calculate pressure loss, size for actual conditions, then verify by measurement.
Pick a dew point below the lowest temperature anywhere in the downstream piping, or water will condense after the dryer. Monitor it where it matters: pharma, instrument air, outdoor lines, electronics, food and critical coating.
The energy cost of treatment
Every element adds pressure drop, and the compressor must run at a higher pressure to make up for it. Watch differential pressure, change filters on condition, size equipment for real flow, keep drains working and avoid over-drying. The aim is the required air quality at the lowest practical lifecycle energy cost.
Eight common mistakes
- Sizing equipment from pipe size instead of flow, pressure, inlet temperature, ambient and dew point.
- Ignoring pressure correction factors (see the correction worksheet).
- Fitting a dryer without pre-filtration.
- Neglecting condensate drains.
- Choosing a lower dew point than the process needs.
- Overlooking filter and dryer pressure drop.
- Giving every application the same air quality.
- Not monitoring dew point, differential pressure and drains.
For critical sites, plan redundancy: duty and standby dryers, duplex filtration, redundant drains, remote alarms and continuous dew-point monitoring.