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Why Condensate Drains are Critical to Compressed Air System Efficiency

Condensate drains are a commonly overlooked and forgotten component in a compressed air system, nevertheless they play a critical role in ensuring an efficient and reliable system. No matter how much investment is made in efficiency boosting features like Variable Speed Drive (VSD), correctly sized air receivers or lowering system pressure for example, neglecting to install and manage condensate drains correctly will offset some or all of your efficiency gains and cause ongoing headaches due to poor system reliability and increased operating costs.

Contaminants such as oil, metal, particles, rust and pipe scale are separated out of the system when separators and filters are working correctly. Condensate drains play a major role in the function of separators and filters and if they do not operate effectively these contaminants can carry downstream in the system and cause piping, instrument and tool damage as well as product spoilage.

Condensate drains improve efficiency by ensuring moisture and contaminants are drained from the system enabling filters and separators to operate at maximum efficiency avoiding carry over and system complications. Condensate that is not drained will carry through the system causing premature wear and tear which will reduce the lifespan of components leading to higher maintenance costs. Condensate can cause catastrophic damage to certain types of dryers and other equipment.

Condensate drains can be found on the intercooler, aftercooler, filter, dryer, receiver or at the point-of-use. There are numerous types and variants of condensate drains, but in most cases each type can be classified in one of two groups:

1)    Manually Controlled

2)    Automatic, No-Loss (Zero Air Loss)

1)   Manually Controlled

Valves are opened manually in these types of drains to remove condensation. As a manual drain it requires human resources to open the valve and drain the condensate at required intervals.

Commonly manual drains are left partially open which is effective at ensuring condensate is continuously removed but the negative is that it will also constantly leak compressed air as well. The resultant air leak leads to a significant drop in efficiency and will be reflected in excess energy usage required to cover the leak.

Alternatively if manual drains are not released at appropriate intervals then moisture and contaminants will carry over and cause damage and complications.

Manual drains are generally not recommended as determining required intervals to open the drain are complicated due to use and environmental factors which are constantly changing and requires a high level of planning to ensure it is managed correctly.

2)   Automatic, No-Loss Drains

Automatic drains continuously measure the amount of condensate present and open to release the condensate at set levels and durations. Automatic, Zero-loss drains also do not expel any compressed air, therefore do not cause any reduction in efficiency which maintains the integrity of the system. As condensate is removed thoroughly when required and without air loss, air quality is maximised as peak efficiency is maintained. The only disadvantage to some automatic drains is in lubricated systems, if not sized properly they can be susceptible to water/oil mixtures that can sludge and jam internal floats causing them to cease to open.

There are numerous types of automatic condensate drains that suit specific applications and operating conditions, these include:

  • Float Type
  • Electronic/Sensor Controlled
  • Timer Controlled
  • Motorised ball drain valve

The drain suited to a particular piece of equipment will depend on a number of variables such as system pressure, hours of operation, human resources to inspect and monitor equipment, temperatures and humidity to name just a few.

It is recommended a compressed air specialist is consulted when selecting condensate drains for your compressed air system as they can assist you in selection of the most appropriate condensate drain for your application. This will ensure efficiency and reliability are maintained and operating costs are minimised long-term.

If you would like assistance or advice on your current condensate drains or selecting the best condensate drains for your application don’t hesitate to contact Southern Cross Compressors on 1300 098 901 or simply complete the ‘Enquire Now’ form on this page.

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rWhat to consider when buying a new air compressor

What do I Need to Consider When Buying a New Air compressor?

When buying a new air compressor, to select the right air compressor is vital to ensure you keep your energy and maintenance costs to a minimum and to deliver long term operating cost savings. Selecting the wrong compressor for your application can lead to thousands of dollars wasted in inefficiencies.

There are a number of things to consider to ensure you get the right air compressor for you, 10 important considerations include:

1) What are you using compressed air for?

How you are going to use the compressed air will dictate the best type of air compressor for your application. Gaining a thorough understanding of your usage by determining how much air you need and when you use it will guide you to the type of air compressor best suited to deliver it efficiently. For existing systems a thorough air audit will help you identify an exact usage profile which can then be used to make informed decisions on requirements.

2) Where are you going to locate the compressor?

Make sure you consider where you will locate the air compressor, if it’s outside shelter and weatherproofing will need to be considered, if inside ventilation and size & configuration will need to be considered. The key to a successful installation is sufficient access for maintenance.

3) How much pressure do you need?

Calculating the minimum pressure you require is vital in terms of maximising efficiency. Every increase of 50 kPag (0.5 bar) in operating pressure results in additional energy consumption of 4%. When applied to a 200 kW compressor an increase of 140 kPag (1.4 bar) in operating pressure results in an increase of over 20 kW in energy consumption, long term that equates to some serious money.

4) How much Free Air Delivery (FAD) do you need?

FAD refers to the maximum amount of air the compressor can produce, measured at inlet conditions. Ensure when selecting a compressor, that the air flow figure quoted is measured in terms of FAD to ensure you are getting an accurate figure of how much air flow the compressor will produce. Some manufacturers may quote figures from the internal parts of the compressor, also ensure the capacity is based on the operating pressure you will work at.

5) How many kilowatts do I need?

Look for a compressor with the highest FAD for the same amount of input power. This means it is a more efficient compressor. The lower the kilowatts of the compressor that can produce the FAD you require will reduce your energy usage and reduce operating costs long term.

6) What size air receiver will I need?

Air receivers act as a buffer for a compressor against constantly cycling on and off load. The larger the air receiver the more compressed air storage, the more protection from cycling and the resulting excessive energy usage and wear and tear on the compressor. You are always better off having an over-sized air receiver than an undersized one.

7) What features should I look for?

There are numerous features depending on the size and type of compressor you are buying. Features like Variable Speed Drive (VSD) may save you more money on energy costs but aren’t suited to every application. The best features to look for with air compressors are the less moving parts the less it’s going to cost in maintenance, things like direct drive airends eliminate belts and gears therefore less parts that may need maintenance. Also look for features like cast iron construction, stainless steel control piping, efficient coolers etc. for efficient and reliable operation reducing long term operating costs.

8) Electrical requirements

It’s important to know what amperage is available at the premises the air compressor will be installed. Each size and type of compressor will have different power requirements so you need to ensure that you’re premises are adequately powered to start and operate the compressor.

9) What control system is best?

There are a number of different control systems available to configure and operate your compressed air system. As mentioned the best control method will also be determined by your usage profile. How much air and when you use it will dictate the most appropriate type of control to maximise efficiency and reliability. Popular control types include start/stop control, constant speed unloading, VSD, modulation and variable displacement.

10) What else is there to consider?

Other considerations should include what moisture removal do I require? As air compresses it produces moisture, that moisture can cause instrument/equipment damage or product spoilage if not removed before end use. You need to know what quality air you require and have the correct aftercooling, drying and filtration to achieve it.

These are some of the main considerations before selecting and installing an air compressor in your plant. The best way to ensure you select and install the right equipment is to speak to a compressed air expert who can advise you correctly.

For expert advice speak to Southern Cross Compressors on 1300 098 901 or simply complete the “Enquire Now’ form on this page.

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reciprocating compressor vs screw compressor

Reciprocating vs. Screw Compressor, Which Should I Buy?

For customers looking for a new air compressor in the 5-15 kW power range this is a common question.

The answer is it depends on the amount and frequency you require compressed air that dictates the type of compressor suited to your application.

If you are a frequent user of compressed air, as in you require compressed air for long durations of time, such as an entire shift, generally a rotary screw compressor would be best suited to your application. Rotary screw compressors perform at peak efficiency when run for long periods of time and are not suited to short periods of demand and long periods off duty. The majority of rotary screw compressors are oil lubricated so not unlike an engine the warmer it gets the better the lubrication and higher the efficiency. Running a rotary screw compressor in short bursts can cause excessive wear and tear due to running cold, decreasing efficiency and increasing maintenance costs. Rotary screw compressors are generally more expensive than reciprocating compressors but they also come with advantages such as superior efficiency (in suitable applications), and can be programmed to turn off during breaks or at the end of the shift to avoid energy usage when no compressed air is required.

Compressed air users that only require short periods of compressed air and have periods of 15 minutes or longer with no demand are generally better suited to a reciprocating compressor. Reciprocating compressors are air cooled so cannot run for long periods of time or overheating issues will arise. Reciprocating compressors are recommended to short duration compressed air applications as they are generally cheaper and have lower maintenance costs.

To determine whether a reciprocating or rotary screw compressor is best for your application than you need to determine your compressed air usage profile to see which compressor will provide the best balance of price, performance, efficiency and maintenance costs over the long term.

If you would like assistance determining the right compressor for your application don’t hesitate to contact Southern Cross Compressor on 1300 098 201 or simply complete the ‘Enquire Now’ form on this page.

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North Queensland Expo - Industrial Air compressors for Sale

Southern Cross & Keypower Exhibit at NQExpo

Southern Cross Compressors recently exhibited at the the inaugural North Queensland EXPO with our newly appointed distributor for the Townsville region Keypower.

The event was designed to support the industry and resource sectors such as transportation, trades, safety, energy and mining throughout North Queensland, with exhibits by suppliers, service providers, government agencies and manufacturers.

It was a great opportunity to find out about opportunities that are developing throughout North Queensland while providing an excellent environment for businesses and visitors to network, market, to obtain suppliers, contractors, products, services and industry contacts.

The event was held over 2 days, unfortunately day one was very wet and this appeared to affect the attendance numbers. Day 2 was a beautiful North Queensland day and all who attended seemed to enjoy the opportunity to view products and speak with suppliers.

The opening event was a breakfast and industry forum that was well attended. The guest speakers spoke positively of the projects that are currently approved and projects that are in the pipeline for the region. It was exciting to hear about the projects and investment that is planned for the region.

Keypower now offers the complete range of air compressors and ancillaries from Southern Cross in the Townsville region. Keypower can be contacted on (07) 4779 8000 or simply complete the ‘Enquire Now’ form on this page for more information on products and services available.

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buy reciprocating compressors online

Buy Reciprocating Compressors Online – New E-Commerce Shop Launched

Southern Cross Compressors has now launched an e-commerce shop on their website to enable customers to buy reciprocating compressors online making the buying process quick and efficient, saving time and money.

The e-commerce platform has been designed to assist informed buyers who do not require the assistance of a Southern Cross expert to quickly and easily select, purchase and take delivery of the reciprocating compressor model suitable for their needs.

The e-commerce platform has been designed to make the process efficient with the addition of features such as:

    • Product descriptions and specifications
    • Freight calculator
    • Select suitable days/times for delivery
    • Secure credit card transaction facility

Once orders are received and payments completed the items will be shipped from our Melbourne Head office to the nominated delivery address promptly.

The KA Series have been hugely popular with Australian customers since their introduction to the market a few years ago. Their slow-revving operation and heavy-duty, cast iron construction have delivered industry leading efficiency and reliability, helping customers minimise their long-term operating costs.buy-reciprocating-compressors-online

KA models from 4 kW to 15 kW in power and 0.52 m³/min to 2.0 m³/min in free air delivery are available and there is a reciprocating compressor to suit any small-medium operation.

The online shop provides customers with a convenient and safe way to buy reciprocating compressors online without the complication of a typical business-to-business purchase.

If you need to replace your current reciprocating compressor or are in need of a new unit, click through to our store to see what’s available and a price delivered to your door.

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Phoenix Air Bundaberg - Air compressors for sale Bundaberg QLD

Southern Cross Initiates Distributor Program Nationally

Southern Cross Compressors (Australia) Pty Ltd has initiated a distributor program to appoint licensed distributors to sell and support the Southern Cross range of compressed air products & services in selected Australian regions to expand brand exposure and increase geographical footprint.

All new distributors have been selected on strict criteria to ensure that the Southern Cross brand is represented and quality service is delivered to all customers nationally, the criteria all new distributors meet includes:

    • Desire and commitment to actively promote the product within their defined region.
    • Previous history of supplying and supporting compressed air equipment to a high standard in the region
    • Business premises that is both professional in appearance and operation
    • Technical and service support capability
    • Willingness to invest in training for sales and service staff
    • Commitment to holding spare parts stock relevant to machines in field.

To date 4 distributors have been appointed, Keypower in Townsville, Comlek in Mackay, Phoenix Air in Bundaberg and Compressed Air Insitu in South Australia. All of these companies meet the criteria above and we are confident they will support you professionally at all times.

All business enquiries will be directed to your nearest Southern Cross or distributor office based on your location. If you have any queries in regard to any of our new distributors or how they can be assistance to any operation you have in these regions don’t hesitate to contact Southern Cross Head Office on (03) 8769 2800.

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Free System Inspection, Consultation & Recommendation Service Available Now

As part of the ongoing mission to help customers ‘lower the cost of compressed air’ Southern Cross Compressors  are now offering free system inspections to review the health of your compressed air system and to identify areas of efficiency improvement to achieve significant operating cost savings.
Compressed air is one of the most expensive energy sources. With the rising costs of electricity, any improvements in efficiency can translate into savings totalling thousands of dollars annually.
System inspections are carried out exclusively by highly trained and experienced staff with extensive industry experience in engineering highly efficient compressed air systems for a range of different industries and applications.
Recently appointed to head site inspections in Victoria is Southern Cross Compressors National Technical Manager, Chris Baksa. Chris’ has over 23 years experience in the compressed air industry and is a valuable resource in assessing and identifying opportunities to improve  system efficiency and reliability.
Chris states that the most common areas for efficiency opportunity are in ‘air leaks, compressor set up, incorrect equipment for the application, poor pipe work and incorrect installation’. Chris highlights that rectifying or removing inefficiencies can lead to massive energy cost savings.
Chris says his focus is providing existing and potential customers with frank, common sense advice to ensure they have the correct set up to provide a high quality and reliable source of compressed air for their plant.
As well as free site inspections Chris can offer further assessment and services such as air audits, air leak audits, airend analysis, oil analysis, overhaul quotes, new and used compressors and ancillary product quotes.
If you think you could benefit from a free site inspection than don’t hesitate to contact Southern Cross Compressors on 1300 098 901 or simply complete the ‘Enquire’ form on this page.
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Melbourne Heatwave Takes its Toll

In early January Melbourne sweated through the worst heatwave in 100 years. Four consecutive days over 40°C and overnight temperatures above 25°C not only took their toll on people but also tested the limits of every compressed air system.
Southern Cross Compressors received a number of calls for help from customers with compressors shutting down due to overheating. The extreme heat caught out many plants that had compressed air equipment not capable of handling these extended periods of extreme heat.
The weather highlighted the importance of ensuring companies select compressors and ancillary equipment designed to handle the Australian climate.
Southern Cross is proud to say that not one of its flagship KHE Series rotary screw compressors failed in the heatwave. The development efforts to produce a compressor to handle all conditions faced in Australia resulted in no recorded downtime experienced by our customers.
Southern Cross understands that downtime is very expensive and the heat highlighted not only the need for equipment designed to handle the Australian climate but also correctly sized aftercoolers and dryers to ensure they are still effective in hot conditions and don’t cause air quality issues to downstream plant processes and instruments.
Ongoing service and maintenance will also ensure that older equipment is in the best condition to handle extreme weather conditions.
If you’re facing issues in the hot weather due to overheating equipment, Southern Cross can review your system and assist you in ensuring you have the most reliable compressed air system to handle Australian conditions.
You can contact Southern Cross Compressors on 1300 101 709 or simply complete the ‘Enquire’ form on this page to get prompt service and advice on this issue.
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Two-Stage Compression Can Save you Thousands of Dollars in Energy & Maintenance Costs

If you require a rotary screw compressor 90kW or above than you should consider the benefits of a two-stage compressor over a typical single stage machine. Single-stage compressors use one airend to compress air to the required system pressure whereas a two-stage compressor separates the compression process over two separate airends.
A two-stage screw compressor can provide total efficiency savings of between 15-20% over a single-stage equivalent screw compressor, resulting in a fast payback on the additional capital investment. In any plant that equates to significant energy and maintenance cost savings per annum. Furthermore, combine two-stage with Variable Speed Drive (VSD) and you have high efficiency over the full demand range.
A two-stage screw compressor works by splitting the compression process between two airends resulting in better efficiency due to a lower compression ratio in each airend. Lower compression ratio’s result in reduced internal losses compared to a single-stage airend.
After compression in the first stage airend the air is intercooled to reduce the temperature which reduces the amount of work required for the second stage airend to achieve the set operating pressure, further boosting efficiency and reducing energy consumption.
The shared compression load results in less axial load on the airend bearings resulting in extended bearing life. This will lower maintenance costs over the life of the compressor.
If you would like more information on the benefits of two-stage screw compressors or the industry leading range of KHE two-stage screw compressors offered by Southern Cross don’t hesitate to contact them on 1300 098 901 or simply complete the ‘Enquire’ form on this page.
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Using the Right Control Method to Minimise Your Operating Costs

There are many types of control method utilised in compressed air systems. Over the last 20 years a number of different control methods have been developed, so identifying the right technology for each individual site can result in significant gains in efficiency and reduction in operating costs.

Common control methods include:

  • Start/Stop
  • Load/Unload
  • Modulation
  • Variable Speed Drive (VSD)
  • Variable Displacement

To determine the control method that will maximise efficiency and minimise your operating costs requires a thorough and detailed usage profile to be established. A usage profile consists of reading and analysing your plants demand for air over time. This is usually collected through the use of an auditing device that can be configured to your compressed air system to measure the air demand in the plant over an extended period. Once a detailed usage profile has been determined it can be analysed and the control method that will deliver the greatest efficiency identified.

Generally there are 4 distinct types of profiles identified in most plants:

1)    Constant Demand

Constant demand occurs when a plant typically requires a consistent amount of air delivery to the plant during all shifts. A plant with a constant demand benefits most from a fixed speed, load/unload controlled air compressor with a correctly sized air receiver to minimise cycles and extend off-load time.

Air Compressor - Constant-Demand-Graph

2)    Widely Varying Demand

Widely varying demand occurs when a plants air demand fluctuates significantly during and between processes and shifts. VSD compressors offer the most efficient control method as a VSD can alter air production to meet the plants requirements at all times ensuring there is no wastage.


3)    Changing Demand

Changing demand profiles occur where there are different air demands between processes and/or shifts. For example a day shift may require a higher volume of compressed air where as a night shift may require only half the amount of the day shift. The best control method for changing demand levels is multiple sequenced compressors. Sequencing multiple compressors enables the system to automatically determine the most efficient operating mode to produce the amount of compressed air required in the plant at any stage during production.


4)    Short Term High Demand

Short term high demand occurs when a plant has specific times of peak demand in an otherwise constant demand profile. There are certain processes that only occur a few times during a shift but require a high level of compressed air. The best control method for short term high demand is generally a fixed speed, load/unload compressor with an engineered air receiver that has enough storage to handle the short peak demands.


Your plant may represent one or a combination of these usage profiles, it is critical an air audit is conducted on your plant to determine a usage profile and the best control method for your application is applied.

Implementing the best control method for your plant will reduce energy and maintenance costs leading to significant savings to your bottom line.

If you would like further advice on control methods or help in determining the best control method for your particular system, don’t hesitate to contact Southern Cross Compressors on 1300 098 901 or simply complete the ‘Enquire’ form on this page.

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Air Compressor Installation – The Key to a Reliable System

When installing a new air compressor, where you choose to install it can have a significant effect on its performance. A poor installation location can dramatically decrease efficiency and increase wear and tear leading to increased operating costs.
There are 4 key factors to consider when deciding where to install your air compressor:
1) Ventilation
One of the leading causes of unscheduled breakdowns is overheating. Because compressed air systems generate large amounts of heat they require effective ventilation.
When there is insufficient ventilation, heated air from the compressor exhaust re-circulates around the unit and is then re-inducted into the compressor increasing the operating temperature of the unit. This will cause the unit temperature to spiral upward and eventually shutdown.
It is advisable to duct the air exhaust of a compressed air system to either an outdoor area or a heat recovery system.
Regardless of how you decide to duct the exhaust heat, addressing this issue at installation time can help extend the life of your compressor.  Specifically, by exhausting the heat, you can lower operating temperatures increasing the life of your coolant, heat exchanger, bearings and hoses whilst lowering residual oil carryover.
2) Maintenance Access
It is important that the installation location allows for adequate maintenance access. Service Technicians need enough room to properly access the compressor to perform preventative and scheduled maintenance and more importantly for any future repairs requiring the removal of component parts within the compressor. If there is not adequate maintenance access than costs will increase as it will take more time and resources to complete service and repair work.
3) Shelter
An option for installation, in order to free up floor space in the plant, is to install compressors outside. If installed outside it is critical that the compressor has a purpose built, well ventilated shelter or enclosure to protect it from rain and UV light.
4) Environment
One common mistake that compressor installers make is that of checking the quality of the air that is drawn into the compressor. To get to know your environment, evaluate the size and make-up of air-borne particulates and ask yourself some questions regarding your surroundings:
• Is the compressor near a chemical process?
• Is chemical cleaning being done in the area?
• Is the compressor likely to ingest abrasive dust particles?
• Are noxious fumes present?
Most environments fall into one of three categories, dusty, hostile and clean.  Here is a brief description and the potential problems:
A clean environment is defined as having low dust and debris.  This type of environment does not require much more beyond what would be considered standard maintenance.
Dusty conditions, on the other hand, may contain abrasive dust as well as dirt, casting sand, and other airborne particulates.  The hazards created by these conditions can be reduced by using a high dust inlet filter.  While it may not remove any additional particles, it can reduce frequency of replacement.
A hostile environment is defined as having caustic gases/chemicals, chlorine, ammonia, acids, in the air.  With a hostile environment, one solution may be to remove the problem by relocating the compressed air system or the hazardous materials.
The best way to ensure you are installing an air compressor in an appropriate location is to consult with a compressed air expert when selecting a location to ensure your compressor runs at peak efficiency and reliability and keeps your operating costs to a minimum.
For more information or advice on selecting a suitable location for your air compressor contact Southern Cross Compressors on 1300 098 901 or simply complete the ‘Enquire’ form on this page.
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air compressors

Pipe Size and Layout Crucial to Minimising Compressed Air Cost

The piping of your compressed air reticulation system can have a dramatic effect on the efficiency and ultimately the cost of running the system.

The main issue causing decreased efficiency within piping systems is pressure drop. Pressure drop occurs due to friction between compressed air and the wall of the piping. When piping is too small to effectively carry the required flow rate to end use, friction within the pipes increases. If this occurs, end use processes may not receive sufficient pressure to operate properly. In this case, most organisations increase pressure at the compressor in turn decreasing efficiency and increases operating costs. If we increase the discharge pressure by as little as 50kPa, the compressor will require an additional 4% energy input to achieve the higher pressure. It also has the added effect of reducing the volumetric efficiency of the compressor. Over a year this can add many thousands of dollars to your energy costs.

There are 3 distinct areas that must be addressed when designing and installing a compressed air reticulation system to minimise pressure drop.

These are:

1)    Size of the piping

2)    The material of the piping

3)    The layout of the piping

Compressed Air Pipe Sizing

When designing a compressed air system it is critical that you correctly size your piping to avoid pressure drop. Sizing of pipe must not only take into consideration current air demand but also any future or expected growth in demand. For example if you set up your system to run 5 air tools and the piping is sized to the exact flow required, if you add any tools or equipment in the future then the piping will become too small, restrict flow and lead to pressure drop. A good rule of thumb is to size piping such that air velocity is maintained below 6m/s.


Compressed Air Pipe Material

There are numerous pipe materials used today such as copper, aluminium, mild steel, plastic and stainless steel.

Piping material can be categorised into two types:

1)     Non-Metal (Plastic)

2)    Metal

Non-Metal or plastic pipe, as it’s commonly referred to, is popular due to:

  • light weight and easy to handle
  • Smooth bore which minimises friction losses
  • Fast & easy to install (can be easily extended)
  • Generally non-corrosive
  • Labour costs are reduced due to shorter install times.

Plastic piping is not suitable for some applications:

  • Most plastic pipes are limited to 60-90°C temperatures before failing
  • Not suitable for high pressure applications
  • Are not compatible with some compressor lubricant types such as synthetic oil
  • In the case of a pipeline fire plastic piping can melt and spread fire inside the plant.

Can be UV unstableMetal piping is commonly used in specific applications due to:

  • Ability to handle higher pressure
  • Can withstand high temperatures
  • Superior lifespan

It’s important to select compressed air piping manufactured in the material that best suits your application to ensure efficiency and long term reliability.


Compressed Air Piping Layout

The layout of the piping in a compressed air system is crucial in reducing pressure drop and minimising operating costs. The further compressed air travels to its end use the larger the pressure drop will be. Minimising the distance compressed air has to travel through a pipe system is the key to increased efficiency. If this is not possible, maximising the pipe size will reduce pressure drop.

The most common piping layout design is the ‘Ring Main’, the loop design allows airflow in two directions resulting in the volume of compressed air carried in each direction being reduced by up to half in most cases. This significantly reduces pressure drop compared to simply having a long pipe run with multiple branches. The ring main design effectively reduces the velocity of airflow through the system in order to reduce pressure drop. Once the ring main has been installed feed lines can then run to feed required production areas and end-use applications as a sub network.

When planning a new compressed air installation it is critical that compressed air piping design and layout is thoroughly thought out otherwise you will lose capacity, reduce efficiency and ultimately increase your operating costs.

If you would like further information on compressed air piping design or installation contact us on 1300 098 901 or simply complete the ‘Enquiry’ form’ on this webpage.

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Pressure Gauge

What is Pressure Drop?

Understanding the Relationship between Pressure Drop and an Increase in Operating Costs

Compressed air is one of the most expensive energy sources in any plant. With the rising costs of electricity maintaining efficiency to minimise operating costs is critical for any compressed air user. One of the biggest issues for compressed air users and a major source of decreased efficiency is pressure drop.

Pressure drop occurs when there is a loss of pressure from the compressor discharge to the actual point-of-use. When pressure drop occurs most compressed air users compensate by increasing the pressure at the compressor. By increasing the pressure at the compressor rather than addressing the issues causing the pressure drop it results in the compressor working harder, reducing output, consuming more electricity and significantly increasing the systems operating cost.

What causes pressure drop?

Pressure drop can be caused by any type of restriction, obstruction or roughness in the compressed air reticulation system causing a restriction of air flow. Once air flow is restricted in any way it results in pressure drop. The main causes of pressure drop can be categorised into 2 sides:

1)Supply Side

2) Demand Side

1)    Supply Side Pressure Drop

The supply side of the system involves the generation of compressed air such as the compressor and ancillaries. The major causes of pressure drop in the supply side are:

  • Air/lubricant separators blocked – although this will show up through higher power bills.
  • Aftercoolers undersized
  • Air filters undersized or blocked
  • Condensate separators
  • Air Dryers undersized

To minimise pressure drop in the supply side of a compressed air system ensure all compressors and ancillary equipment are correctly sized and selected to suit your particular application and ensure all equipment is regularly monitored and serviced to ensure maximum efficiency is maintained.


2)    Demand Side

The demand side of a compressed air system involves the reticulation system (piping) and the points-of-use. The major causes of pressure drop in the demand side of a compressed air system are:

  • Undersized piping
  • Unsuitable piping material
  • Poor piping layout
  • Air leaks in the reticulation system
  • Undersized or leaking hoses

To minimise pressure drop on the demand side of the compressed air system care should be taken in the selection of compressed air piping size, material and layout to ensure that compressed air will travel through the distribution system with minimal restriction taking the shortest path possible to its end-use application. A focus on not only current demand but future growth in demand for compressed air should be taken into consideration to avoid future pressure drop problems. Also a regular air leak maintenance plan should be in effect to minimise pressure drop and loss of efficiency.

If you are experiencing problems with pressure drop or planning a new installation contact us for expert advice on obtaining maximum efficiency for your compressed air system.

Call us on 1300 098 201 or simply fill in the ‘Enquiry Form’ on this page.

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Air Compressors Air End Room

New Air Compressor Rebuild Centre Completed

A key feature of the new Southern Cross Keysborough operation is a state of the art airend rebuild centre. This specialised workshop is where customers rotary screw air ends will be returned to original manufacturers specifications.

Rebuilding a rotary screw airend requires specialist skills, tools and equipment. Southern Cross has invested in a first class facility to gives us the best chance of getting the optimum service life out of an airend. Rotary screw air ends, like any rotating equipment, require overhaul from time to time. These precision engineered components are the heart of any screw compressor. Correct bearing replacement must be undertaken in a controlled environment to prevent dust and other contaminants from impacting the life of new bearings.

The new Southern Cross rebuild centre has been equipped with an extensive inventory of equipment including:

  • Negative pressure dust control centre
  • Electric over head crane
  • Rotating table
  • Bearing induction heater
  • Crack detection equipment
  • Specialised bearing removal tools
  • Dial indicators
  • We also have an extensive machine shop including, lathe, pedestal drills, welding equipment, parts washing machine, grinding and polishing equipment.

As air ends are manufactured to fine tolerances, it is critical that a rebuilt airend meets exact manufacturer requirements to ensure it operates at its optimal efficiency in order to minimise operating costs. This has been the focus when designing the new rebuild centre. The new rebuild centre has been designed to complete air end rebuilds on rotary screw airends and gas ends up to 400 kW, both single and two stage models.

Every resource required has been integrated into the new rebuild centre so that we can offer customers an air end rebuild service, delivering superior efficiency and reliability with a fast turnaround time.

At Southern Cross Compressors we have been rebuilding air ends from virtually every make and model air compressor manufactured over the last 30 years. Whatever the make and model rotary screw compressor we have the expertise and resources to ensure a first class job.

If you would like more information on our new rebuild centre or our air end rebuild capabilities don’t hesitate to contact us on 1300 101 709 or simply complete the ‘Enquiry’ form on this page.

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Container KHE Air Compressors

Custom Engineered Air Compressor Packages

Some environments and applications have requirements that cannot be met from a factory standard air compressor package; therefore, a customised solution is required. At Southern Cross Compressors we have been designing, constructing and installing custom engineered compressed air packages for over 30 years.

Industries such as mining, oil & gas and  other harsh environments typically require customised solutions.. At Southern Cross we have designed customised air compressor solutions for a myriad of different industries to meet specific air and efficiency demands.

Whether a skid mounted compressor, containerised package or a weatherproof compressor solution, we have the expertise to meet a customer’s specific requirement.

At Southern Cross Compressors we have the in house expertise to complete engineering designs general arrangement drawings, electrical schematics, P&ID’s  and special operating manuals.

Coupled with our expertise we have resources such as environmentally controlled spray booth for high quality surface treatments, welding shop, fabrication shop, machining centre and extensive range of materials for construction and piping including copper, mild steel, polypropylene and stainless steel.

Our latest custom engineered compressor package involved a fully containerised, factory tested instrument air package complete with interconnecting pipe work and wiring designed to operate in a harsh environment. A ventilation system and ductwork were incorporated as part of the installation. The package was customised to have only one air pipe connection and one electrical connection to simplify on site installation. The package can be easily removed or installed and can be transported by road, rail or water for maximum convenience.

If you would like to know more about our capabilities in custom engineered air compressor packages or simply would like some more information don’t hesitate to contact us on 1300 098 201 or simply complete the ‘Enquiry’ form on this page.

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Air Dryer Installation

Correctly Sizing your Refrigerated Air Dryer is critical if you need dry air.

Refrigerated air dryers are the most popular choice in removing condensate (water) from a compressed air system. Removing water from a compressed air system is crucial in the majority of applications as water can cause instrument/tool damage, product spoilage, pipe corrosion and higher maintenance costs.

The type of air dryer selected depends on the level of moisture required to be removed from the compressed air for each specific application. Selecting the right dryer is critical. However, the first step in condensate removal is the installation of an effective aftercooler and condensate separator. An aftercooler will not only remove approximately 65-75% of the moisture from compressed air it also lowers the temperature such that it is cool enough the dryer select. A coalescing filter prior to the dryer will remove contaminants which is crucial as an air dryer needs to be free from contaminants to be effective.

An aftercooler will cool compressed air to approximately 10°C above ambient temperature whilst a correctly sized refrigerated air dryer will reduce the temperature to between 1°C &4°C removing approximately 95% of the moisture contained in compressed air. At 95% condensate removal, most systems will not see any liquid downstream of a correctly sized refrigerated air dryer.

If a refrigerated air dryer is not sized correctly for a particular system then issues such as overheating, decreased efficiency and shut-down are common leading to moisture in your system and the dryer rendered ineffective.

To determine the correctly sized dryer for your application there are 5 variables that must be considered including:

1)    Flow Rate (Free Air Delivery (FAD))

The flow rate is determined by the FAD of your air compressor(s) to determine the minimum flow the refrigerated air dryer needs to be able to process. For example an 8 bar, 75kW KHE Series Rotary Screw Compressor has a FAD of 14.18m³/min.

2)    Operating Pressure

Refrigerated air dryers are usually specified at a 7 bar operating pressure. Therefore a compressor operating at 8 bar would require a correction factor to be applied. The correction factor table below indicates that for 8 bar operating pressure the dryer has a capacity of 1.06 times that of its capacity at 7 bar. .








Correction Factor








3)    Maximum Ambient Temperature

The maximum ambient temperature of the environment the refrigerated dryer will be located must be considered in the calculation. It is important in Australia that dryers are selected to handle the ambient temperatures that we typically encounter during our summer months. An undersized dryer not selected to handle these temperatures may shut down and fail. Always check when purchasing an air dryer that it is rated to handle our ambient temperatures as some European models are designed for only 25°C conditions. A Southern Cross air dryers are always selected for a minimum ambient of 35°C. A correction factor would be applied for dryers operating at different capacities.








Correction Factor








4)    Maximum Inlet Air Temperature

The inlet air temperature refers to the temperature of the compressed air as it enters the dryer. An effective aftercooler will reduce the temperature of the compressed air to around 10°C above ambient. An air dryer selected for an ambient temperature of 35°C will typically experience an inlet temperature of 45°C. If the inlet air temperature is above 45°C temperature another correction factor must be applied. .








Correction Factor








5)    Pressure Dew Point

The pressure dew point is the point at which water vapour turns to liquid. A correctly sized dryer will lower the pressure dewpoint such that moisture is turned to liquid which can be easily removed. As a standard in Australia most refrigerated air dryers are selected to achieve a pressure dew pint of 3°C. In our example we will select our dryer at the nominated pressure dew point of 3°C. Once again, if a higher pressure dewpoint is OK, the dryer capacity can be adjusted.







Correction Factor







To complete the calculation and get the ‘actual flow rate’ required by a refrigerated air dryer to suit our compressed air system we perform the calculation as follows:

FAD x Correction Factor (Working Pressure) x Correction Factor (Ambient Temperature) x Correction Factor (Inlet Temperature) x Correction Factor (Pressure Dew Point) = Actual Flow Rate of Dryer Required.

So the actual calculation would be:

14.18 x 1.06 x 1 x 1 x 1 = 15.03 m³/min.

This calculation means when selecting a refrigerated air dryer to suite our 75kW compressed air system the dryer needs to be able to process at least 15.03 m³/min of air flow to operate at full efficiency. So when selecting a model we would select the correct model designed to handle 15.03 m³/min or more to ensure a reliable source of dry compressed air.

If you would like more information on selecting and sizing a suitable refrigerated air dryer for your application don’t hesitate to contact us on 1300 098 901 or simply complete the ‘Enquiry Form’ on this page.

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