Here are a few guidelines on how to keep your reciprocating air compressor working optimally. No matter what brand of oil-lubricated reciprocating compressor you own, doing the following three things on a regular basis will extend its working life helping to ensure a trustworthy tool for years to come:
- Change lubricant quarterly
- Purge water from tank weekly (at least)
- Change air filter quarterly
Your reciprocating air compressor is basically an engine, and as such it requires constant lubrication to prevent excessive friction from damaging the moving parts and ultimately seizing the piston/s. Non detergent lubricants are typically preferred for reciprocating air compressors, but make sure you respect the viscosity the manufacturer suggests for your particular compressor.
Regularly check the oil level to make sure you have the right amount of oil in the crankcase. While the dangers of too little oil are obvious, it’s also important not to overfill a compressor with oil. If the oil level is too high the oil can get whipped and it will foam up, losing some of its lubricating properties. In addition, it will gain volume, further increasing your problems. So keep checking with your dipstick/gauge as you refill with oil and make sure your unit is perfectly level to the ground when you do this.
These are just as easy to read as the dipstick variety. The red dot represents the “OK” mark (I don’t know why they paint it red, should’ve been green). Ideally you want to keep the oil level within the center of the dot, but as long as the level is within the dot, you are OK.
On these it’s also easier to judge the state of the oil by looking at it with a flashlight, you can often see whether it’s getting milky (water) or darker (regular wear) without having to remove a sample from the crankcase.
Tip #1-Oil is regularly lost through the exhaust and the breather hole on the crankcase. Oil also ages and because of this, you should replace the oil after a certain amount of duty hours. A good rule of thumb that will help you comply with most manufacturer’s requirements is to change your reciprocating compressor oil on a quarterly basis. The actual time depends on many factors and its best if you obtain the manual for your particular compressor for a clear indication on when to replace the oil.
To remove the old oil there’s going to be a bolt at the bottom side or the bottom of the crankcase in all reciprocating air compressors. Simply remove this bolt to allow the old oil to drain into a bucket for proper disposal. To speed up the process, make sure you remove the oil when it’s warm and remove the filling cap so you don’t draw a vacuum.=
Removing Condensate from the Receiver Tank
As the compressor’s intake happens to be ambient air, humidity in the air is sucked in on every cycle. The water vapor from ambient humidity will condense and accumulate in the tank/s. Because of this dynamic, it’s imperative to drain the tank/s at least once a week.
Draining the tank is easy. Locate the drain valve at the bottom of the tank and open it until moisture and air come out of the valve. As soon as the flow of water slows to a trickle, close the valve.
If you don’t drain the tank the condensate will rust the tank’s envelope and ultimately corrosion and rust-through will occur. The more the condensate sits in the tank, the worse it’ll get in time.
To keep condensate from building up in the receiver tank with minimal effort, include the automatic electric timer drain with your purchase of a new compressor. An electric timer drain will open at preset intervals to keep condensate from building up in the tank and finding its way down stream to the shop equipment. Zero-loss drain valves do the same thing, but they lose less compressed air pressure and also reduce the number of short cycles needed to keep the compressed air system at the pre-set level. This saves on your electricity bill.
Tip #2- Because eliminating condensate from the tank is so important to the life of your compressed air system, put a tickler on your calendar to drain the tank at least once a week –more frequently in humid environments. Better yet, automate this task by investing in an automatic tank drain.
Intake Air Filter
The intake air filter is there to stop the compressor from taking in particles of dust in the ambient air which might cause damage to the metal surfaces inside the air compressor. If the location of the compressor has a lot of dust and dirt in the air, this filter may need to be kept clean or changed more often than the manufacturer’s recommendations. Use the manufacturer’s replacement intake air filter for proper fit and filtration.
Tip #3 – Refer to your manufacturer’s recommended intake air filter replacement schedule. Replacement of your intake filter is important to keeping your air compressor in compliance with the manufacturer’s basic and extended warranty. Even if your air compressor is out of warranty,
With high summer temperatures fast approaching please make sure your rotary compressor is prepared for the change in climate. Here are 4 tips to keep your rotary compression at peak performance for the summer.
- Lubricant and Coolant Levels
Is your lubricant and coolant low? Is it due for a fluid and filters service? Please note that running FS-Curtis synthetic fluids will reduce the heat generated by your compressor. The compressor oil serves as coolant in oil flooded rotary compressors. In rotary compressors, the compressor oil is circulated 7 or more times per minute through the machine. This is why oil levels become more critical in the summer. To be sure of the condition of your air-end and bearings we recommend an oil analysis by a distributor.
- Air Density
In the summer your compressor will have a lower performance. Make sure you install a new intake filter for the hot summer days. Please be aware that dirtier environments require more frequent intake air filter changes.
- Having Clean Compressor Air and Oil Coolers
A clean cooler may be the difference between normal operation and a high temperature shut down. Many times synthetic compressor oils are fruitless because the oil breaks down prematurely due to overheating. To protect from high acid numbers, loss of lubricity and increased viscosity, long oil change intervals must be monitored with frequent lube analysis, particularly when exposed to high ambient temperatures. Please contact your local FS-Curtis service company for a compressor “health” check.
- Hot Ambient Air and Moisture
Most lubricated, air cooled, rotary screw compressors run 100 to 110 degrees F above the ambient temperature. If your compressor room temperature is over 100 degrees F, you are already in trouble. Cross flow ventilation is advisable in non ducted compressors. If your compressor oil sump or air-end discharge is more than 120 degrees F over ambient temperature in the room, you need to find out why. FS Curtis has factory approved Air Treatment accessories to minimize moisture in your system and air lines.
Small adjustments can reduce your operating pressure and energy costs while improving flow rates and output. Learn the final steps you can take to optimize your compressed air system and save energy costs. But, make sure that you also check out the first 5 things you can learn to "Save your Compressed Air System Operating Costs"
- Review Piping Infrastructure. Many systems aren't optimized.
A piping system design should optimize transfer of compressed air at the desired flow and pressure to the point of use. Increasing the size of a pipe from two to three inches can reduce pressure drop up to 50 percent. Shortening the distance air has to travel can further reduce pressure drops by about 20-40 percent.
The more flow through a pipe the greater the pressure drop will be. Pressure drop in a pipe increases with the square increase in flow, which means if the flow is doubled, the pressure drop will increase four times. Air distribution piping should be large enough in diameter to minimize pressure drop.
If your compressed air piping system was installed years ago when your compressor was much smaller, this might be an indication that the distribution pipes are too small. A quick guide is to look at the air compressor outlet size. If your distribution piping is smaller than your air compressor outlet size, then it may be time to get your FS-Curtis distributor in to evaluate your piping system. If up-grades are needed, FS-Curtis offers a modular, aluminum piping system that is easy to install and is a cost effective alternative to copper or steel piping.
- Change Filters Systematically. Not every once in a while.
Inspect and replace filters systematically to ensure the quality of your air and prevent pressure drops. Go beyond the air compressor and compressor room. There are several air-line and point-of-use filters within the facility. Those are just as important to maintain as the air compressor and air compressor room filters.
Your FS-Curtis distributor will provide you with a complete Filter Package located on your compressed air system supply side. Your process and type of equipment used will determine the level of air quality needed. If you are not sure what you need, ask your FS-Curtis distributor who can guide your selection using an industry standard selection chart.
- Recover Heat. Compressing air generates heat - reuse it!
It's simple physics that compressing air gives off heat, and as much as 90 percent of that heat can be recovered for use in your operation. For example, you can produce hot water for washrooms or direct warm air into a work space, warehouse, loading dock, or entryway. The savings can really add up.
How can FS-Curtis features and benefits help with this step? A simple heat recovery step can be making sure the hot air from your compressor room is directed into a nearby work space. If you have a larger rotary screw compressor with e-COOL® Technology, you could capture the exhaust air from your air compressor and ducting into your facility during the heating season. More aggressive heat recovery systems can be used to pre-heat water or process materials if you operate larger compressor systems.
- Emphasize Proper Maintenance. Ignoring maintenance costs more.
As with most industrial machinery, a compressor runs more efficiently when properly maintained. Proper compressor maintenance cuts energy costs around one percent and helps prevent breakdowns that result in downtime and lost production. Protect your reputation and profits with proper maintenance.
Your FS-Curtis i-Command® Touch Control will help monitor your compressor for items needing maintenance as well as sending signals showing maintenance alerts. Having your FS-Curtis distributor establish a scheduled service interval based on the number of hours your compressor runs per year will save you money in the long run. Take advantage of your extended warranty by using correct parts and lubricants at the correct time. If you skip service and have maintenance done, then you can expect that future warranty claims may be rejected. Just like you car, if you don’t take care of it, it won’t take care of you!
- Identify and Eliminate Inappropriate Uses of Compressed Air.
Inappropriate uses of compressed air include any application that can be done more effectively or more efficiently by a method other than compressed air. For example, high pressure air often is used for cooling or applications where much lower air pressure is required.
If you have a Compressed Air Leak Survey scheduled, the Auditor normally is looking for inappropriate uses of compressed air at the same time. Common missuses are: blowing off a work station with an air gun instead of using a hand brush; using an air stream as a personal cooler instead of a fan; plus many, many more ways.
Each manufacturer’s make and model of rotary air compressor gives specific guidelines for preventative maintenance in the operations manual sent with the air compressor. You’ve invested a good deal of money in your new compressor, to protect your new investment it’s a wise idea to follow these preventative maintenance procedures. Keep in mind this is not a comprehensive list, but it’s a good start and will help give peace of mind knowing you are not neglecting your air compressor.
Every manufacturer of rotary screw air compressors provide an Operators Manual with specific guidelines for preventative maintenance. You’ve invested a good deal of money in your new compressor, to protect your new investment it’s a wise idea to follow the preventative maintenance procedures. Some compressor designs may require more steps and checks, but here is a good place to start to get the longest life out of your investment.
Daily: Check for abnormalities (unusual sound, vibration, leaks, warnings or alarms on the controller, etc.)
- Check oil level
- Monitor temperature and pressure
- Check control panel for any alarms or maintenance lights
Monthly: Perform Daily checks
- Clean inlet air filter and enclosure filters.
- Check operation (load and unload, low and high pressure set-points, maintaining pressure, etc)
Quarterly: Check hour meter and check the maintenance schedule to determine if its time for maintenance to be scheduled. Your compressor may require lubrication change at 2,000, 4,000 or 8,000 hours depending on the manufacturer’s recommendations.
- Take oil sample if needed
- Check separator scavenger line flow (if applicable)
- Check v-belts (if applicable)
- Perform daily and monthly checks
Semi-Annual or 4000 hours: Perform Quarterly Check list.
- Change air/oil separator filters (spin on or drop in type)
- Take oil sample and sent to compressor vendor
Annual or 8000 hours: Start by checking annual maintenance list for manufacturer’s recommendations:
- Change lubricant
- Change air / oil separator (drop in type)
- Perform quarterly checks
Keep in mind; these are the basic maintenance items needed to keep an oil flooded rotary screw compressor in good operation. This preventative maintenance program is designed for a standard condition, but as we all know most installations for air compressors would be considered dirty and dusty environments.
Another factor that is critical to the life of a compressor is the actual run time. All rotary screw compressors underlying guideline for maintenance is hours of operation. Most installations never operate 24 hrs per day / 7 days a week. There are only 8760 hours in a year and anything less than 24 hours will result in lower hours, which affect the amount of maintenance needed for each installation.
So, with all of these factors to consider, what does an owner of an oil flooded rotary screw compressor do to properly maintain the air compressor to ensure long reliable operation?
To answer this question we need to look at several factors:
First the environment is the one factor that governs all of the others. If your compressor is running in a dirty environment where you have to keep cleaning the coolers externally to keep the compressor cool and the air filter is continually dirty when you inspect it periodically; then you have a dirty environment. Use the monthly recommendations and not the hours of run time.
2) Hours of operation (less than 4000 hrs per year)
In this case the recommendation would be to follow the time frame set out for preventative maintenance as described in the operations manual. Use monthly intervals for filter changes and not the hours of operation as your guide. This means air and oil filters changed every quarter (or more frequently) as well as air/oil separators changed per instruction manual. Please note if you are running 24 hrs / 7 days then air and oil filters will need to be changed in accordance with OEM recommendations.
Costs of preventative maintenance should be only considered as a last resort as it has been proven in many studies that preventative maintenance saves money. A proper preventative maintenance program will translate into more reliable operation and less down times for the owner. This will create a more efficient production process for the owner which generates income on a consistent basis.
In all other instances the OEM manual should be used as a guideline for changing all filters for the proper maintenance your rotary screw compressor.
A properly maintained air compressor can be accomplished by following several practical guidelines and discussing your needs with an FS-Curtis compressed air professional. To learn more download the product information or contact your local FS Curtis distributor.
How do you choose the right oil for your air compressor?
Question: Would you dump lawnmower oil into your car's engine? Probably not. Your neighbor's, maybe, but not your precious heap of a jalopy.
The same strategy holds true for your air compressor. Just like automobile oil, there are many different grades of air compressor oil to choose from, each designed to meet certain specifications.
Two main factors are involved in choosing the correct oil:
1) The type of compressor. Rotary screw or recip?
2) The environment your compressor operates in. Hot, humid temperatures? Cold? Dirty air? Clean, sterile environment?
Many compressors, many environments, many choices.
Solution? Of course, there is. What's a riddle without an answer?
To help ease your pain when choosing oil for your compressor, FS-Curtis has introduced two new fluid lines: FSC-Max Fluid and Pro Fluid.
FSC-Max Fluid is our core fluid product line and comes with a bold new look. Designed to offer the highest protection for your FS-Curtis products and to operate at 100% efficiency in virtually all environments, FSC-Max will help run your unit efficiently and smoothly in various environments from food grade applications to large industrial.
How much faith do we have in the FSC-Max Fluid line? All FS-Curtis products are tested and shipped from our headquarters and plant in St. Louis, MO., using FSC-Max Fluid.
It's also the only lubricant product line that can validate FS-Curtis extended warranty programs.This is important in order to protect your investment and ensure its longevity.
Pro Fluid is a great new addition to our professional grade line of products and offers a full range of fluid choices for virtually all circumstances. It is also an ideal economical alternative for OEM replacement fluids, and a great choice when servicing industrial machinery.
For more information about which fluid is the best choice for your compressor, ask your FS-Curtis sales representative, call our service representatives at 314-383-1300 or visit our website at us.fscurtis.com