Posts Tagged ‘Compressor Maintenance’

Ask a Question:
What are some good trouble shooting tips to help me maintain my compressed air system?

Answer:
Here are some great Air Compressor Trouble Shooting Tips
to help you or anyone providing the regular maintenance for your compressed air system.

Below are listed several very common problems, their probable cause and some usual remedies for the trouble.

Of course, there can be multiple problems and unique circumstances to every compressor issue…but these tend to solve the most common situations.

PROBLEM:
Low pressure at point of use

Probable Cause: Remedial Action
Leaks in distribution piping: Check lines, connections and valves for leaks
Clogged filter elements: Clean or replace filter elements
Fouled dryer heat exchanger: Clean heat exchanger
Low pressure at compressor discharge: See below

PROBLEM:
Low pressure at compressor discharge

Probable Cause: Remedial Action
For systems with modulating load controls, improper adjustment of air capacity system:
Follow manufacturer’s recommendation for adjustment of air capacity system

Worn or broken valves Improper air pressure switch setting:  Check valves and repair or replace as required
Follow manufacturer’s recommendations for setting air pressure switch

Improper air pressure switch setting: Follow manufacturer’s recommendations for setting air pressure switch

PROBLEM:
Water in lines

Probable Cause: Remedial Action
Failed condensate traps: Clean, repair, or replace the trap
Failed or undersized compressed air dryer: Repair or replace dryer.  If you do not have an Compressed Air Dryer, consider adding this equipment.

PROBLEM:
Liquid oil in air lines

Probable Cause:  Remedial Action
Faulty air/oil separation: Check air/oil separation system; change separator element
Compressor oil level too high:  Follow manufacturer’s recommendation for proper oil level

PROBLEM:
Dirt, rust or scale in air lines

Probable Cause: Remedial Action
In the absence of liquid water, normal aging of the air lines: Install filters at point of use

PROBLEM:
Excessive service to load/hour ratio

Probable Cause: Remedial Action
System idling too much:
For multiple compressor system: consider sequencing controls to minimize compressor idle time
Adjust idle time according to manufacturer’s recommendations

Improper pressure switch setting: Readjust according to manufacturer’s recommendations

PROBLEM:
Elevated compressor temperature

Probable Cause: Remedial Action
Restricted air flow: Clean cooler exterior and check inlet filter mats

PROBLEM:
Restricted water flow

Remedial Action:
Check water flow, pressure, and quality; clean heat exchanger as needed

PROBLEM:
Low oil level

Remedial Action:
Check compressor oil level, add oil as required

PROBLEM:
Restricted oil flow

Remedial Action:
Remove restriction, replace parts as required

PROBLEM:
Excessive ambient temperature

Remedial Action:
Improper ventilation to compressor; check with manufacturer to determine maximum operating temperature.

Owned & Operated by
Tommy McGuire
McGuire Air Compressors, Inc.
“Real People with Real Air Compressor Experience”

For Champion Air Compressors…
http://www.industrialaircompressors.biz/

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plus Electric Cord Reels & Welding Cable Reels…
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to remove moisture from your compressed air system…
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Email us:
compressors@mcguire.biz

Call us:
1-888-229-9999

Mailing address:
McGuire Air Compressors,Inc.
P.O. Box 1100
Graham NC  27253

 

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Figuring the correct pipe size for your compressed air distribution system is an important task. 
Pipe that is sized too small can create big pressure losses and reduce operating efficiency. Replacing piping is costly.  On average, 70% of a contracted piping job goes for labor and 30% for materials.

Do you know the biggest mistakes made in figuring compressed air piping sizes?
Many people who plan the piping never consider the fittings or the future.

FITTINGS:
Every pipe fitting creates a certain amount of increased frictional air loss that is equal to a specified length of pipe.
For every 100 feet of pipe you will have a ONE POUND PRESSURE DROP caused by frictional air loss.
Any turns in the pipe at fittings, ells, tees, and valves increase pressure drops even more.  That’s why the EQUIVALENT LENGTH OF PIPE (FT.) for PIPE FITTINGS chart was developed to help you determine the best pipe size for your system.

FUTURE:
Are you planning to add more equipment in the next year or two?  Then plan for larger piping now.  Since the material costs in piping are low compared to installation or replacement cost, it’s wise to select pipe of an adequate size. If there is any doubt that a pipe size may create a pressure drop, use the next largest size. Remember that an oversize pipe compensates for possible scale build-up and provides for future expansion of the overall air system.

Steps to figuring what size piping your compressed air system needs:

  1. Determine your air compressor’s maximum CFM.
  2. Draw a piping schematic and show all pipe fittings, valves, etc.
  3. Measure and write the corresponding lengths of pipe on your schematic, then total the length of all straight pipes needed and note that on your schematic.
  4. Using TABLE 1, find your compressor’s CFM number on the far left column,
    and then go to the right until you see the column header with nearest length in feet to your total pipe length. Find where the CFM & PIPE LENGTH intersect on the chart and it will show the recommended pipe size for that length.
  5. Take that pipe size to TABLE 2 and use the table to find all the EQUIVELENT LENGTHS OF PIPE needed for each PIPE FITTING.  Write these lengths on your piping schematic at each fitting.
  6. TOTAL all the EQUIVELENT LENGTHS OF PIPE needed for each PIPE FITTING and add to your total of straight length of pipe.  This will give you a new and more accurate total pipe length needed.
  7.  Take your new total of EQUIVELENT LENGTH OF PIPE IN FEET back to TABLE 1 and use this number to determine the PIPE SIZE you need.
  8. Think of the FUTURE!
    Now is the time to plan for larger piping that may needed for additional future equipment.
How to figure the right air pipe size

Table 1- The right pipe size

Table 2 - to help figure the right air piping size

Table 2 - to help figure the right air piping size

Leaks can be a big source of wasted energy in an industrial compressed air system, sometimes wasting 20 to 30 percent of a compressor’s output. A typical plant that has not been well maintained will likely have a leak rate equal to 20 percent of total compressed air production capacity. On the other hand, proactive leak detection and repair can reduce leaks to less than 10 percent of compressor output.

In addition to being a source of wasted energy, leaks can also contribute to other operating losses.
Leaks cause a drop in system pressure, which can make air tools function less efficiently, adversely affecting production. In addition, by forcing the equipment to run longer, leaks shorten the life of almost all system equipment (including the compressor package itself).

Increased running time can also lead to additional maintenance requirements and increased unscheduled downtime. Finally, leaks can lead to adding unnecessary compressor capacity.

Q. Where do most leaks usually occur?

Answer:
While leakage can come from any part of the system, the most common problem areas are:

• Couplings, hoses, tubes, and fittings

• Pressure regulators

• Open condensate traps and shut-off valves

• Pipe joints, disconnects, and thread sealants.

Q. How much can compressor leaks cost my business?

Answer:
A small leak – no larger than 1/16″ can cost an extra $523 a year*.
Add a few other small leaks here and there until you have leaks equal to a 1/4″ opening…and now that “small leak” can cost you $8,382 a year.*  It is easy to see that what seems like a small leak comes with a very high price tag over time.

*Costs calculated using electricity rate of $0.05 per kilowatt-hour, assuming constant operation and an efficient compressor.

Q. How do you estimate the SIZE of AIR LEAKS?
Answer:
It’s not very hard.  We’ll use the “TIME METHOD” to estimate percentage % of loss due to air leaks in your plant. 

1-    Turn OFF all air operated end-user equipment.
2-    Start your air compressor and let it cycle 3 times
3-    Time the OFF-LINE / UNLOAD TIME (not pumping time) using your watch. (Example: 5 minutes)|
4-   Time the ON-LINE / LOAD TIME (pumping time) using your watch. (Example: 2 minutes)
5-   Calculate total percentage of air leaks as follows:

Add the OFF / UNLOAD and the ON / LOAD times together:

Example: T(5 minutes)  +  T (2 minutes)= 7 minutes
Divide  ON / LOAD time T (2 minutes) by the total minutes: 2 ÷ 7 = 0.29

The result tells you 29% of your air compressor’s CFM’s are maintaining your AIR LEAKS.
This would mean that you are losing almost ONE THIRD of your compressed air to air leaks. 

Q. What’s the best way to detect and fix compressor leaks?

Answer:
Since air leaks are almost impossible to see, other methods must be used to locate them.

The best way to detect leaks is to use an ultrasonic acoustic detector, which can recognize the high-frequency hissing sounds associated with air leaks. These portable units consist of directional microphones, amplifiers, and audio filters, and usually have either visual indicators or earphones to detect leaks.

A simpler method is to apply soapy water with a paint brush to suspect areas. Although reliable, this method can be time consuming.

Click here to see how to estimate the SIZE of AIR LEAKS.

Q. How To Fix Leaks

Answer:
Leaks occur most often at joints and connections. 

Stopping leaks can be as simple as tightening a connection or as complex as replacing faulty equipment, such as couplings, fittings, pipe sections, hoses, joints, drains, and traps. In many cases, leaks are caused by failing to clean the threads or by bad or improperly applied thread sealant. Select high quality fittings, disconnects, hose, tubing, and install them properly with appropriate thread sealant.

Non-operating equipment can be an additional source of leaks. Equipment no longer in use should be isolated with a valve in the distribution system.

Another way to reduce leaks is to lower the air pressure of the system. The lower the pressure differential across an orifice or leak, the lower the rate of flow, so reduced system pressure will result in reduced leakage rates. Stabilizing the system header pressure at its lowest practical range will minimize the leakage rate for the system. Once leaks have been repaired, the compressor control system must be re-evaluated to realize the total savings potential.

Establishing a Leak Prevention Program

There are two basic types of leak repair programs:

1. The leak tag program
2. The seek and repair program.

The” seek and repair” method is the simplest. As it states, you simply find the leak and repair it immediately.

With the leak tag program, the leak is identified with a tag and logged for repair at a later time. This is often a two-part tag; one part stays on the leak and the other part is turned into the maintenance department, identifying the location, size, and description of the leak to be repaired. The best approach depends on the type, size, and the culture/work practices of the facility. It is more likely that the best solution will be a combination of the two.

*SOURCE:  Based on definitions taken from “Improving Compressed Air System Performance” published as a cooperative effort of the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) Best Practices and the Compressed Air Challenge®.

 

Tommy McGuire
Owner of McGuire Air Compressors
“Real People with Real Air Compressor Experience”
888-229-9999

Email:compressors@mcguire.biz

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Ask a Question:
What causes pressure drop in my compressed air system?

 Answer:
Any type of obstruction, restriction, or roughness in the system will cause resistance to air flow and cause pressure drop.

 

 

In the distribution system

, the highest pressure drops usually are found at the points-of-use, including undersized or leaking hoses, tubes, disconnects, filters, regulators and lubricators (FRLs).
 

 

On the supply side of the system

, air/lubricant separators, aftercoolers, moisture separators, dryers and filters can be the main items causing significant pressure drops. The maximum pressure drop from the supply side to the points-of-use will occur when the compressed air flow rate and temperature are highest.
Your Compressed Air System components should be selected based upon these conditions and the manufacturer of each component should be requested to supply pressure drop information under these conditions.

When selecting filters, remember that they will get dirty.
Dirt loading characteristics are also important selection criteria. Large end users who purchase substantial quantities of components should work with their suppliers to ensure that products meet the desired specifications for differential pressure and other characteristics.

 

 

The distribution piping system

often is diagnosed as having excess pressure drop because a point-of-use pressure regulator cannot sustain the required downstream pressure. If such a regulator is set at 85 psig and the regulator and/or the upstream filter has a pressure drop of 20 psi, the system upstream of the filter and regulator would have to maintain at least 105 psig. The 20 psi pressure drop may be blamed on the system piping rather than on the components at fault. The correct diagnosis requires pressure measurements at different points in the system to identify the component(s) causing the excess pressure drop. In this case, the filter element should be replaced or the filter regulator size needs to be increased, not the piping.
 

 

How to Minimize Pressure Drop

Minimizing pressure drop requires a “systems approach” in design and maintenance of the system.   
Air treatment components, such as aftercoolers, moisture separators, dryers, and filters, should be selected with the lowest possible pressure drop at specified maximum operating conditions.
 
When installed, the recommended maintenance procedures should be followed and documented.

Additional ways to minimize pressure drop are as follows:
 

 

• Properly design the distribution system.
 

 

• Operate and maintain air filtering and drying equipment to reduce the effects of moisture, such as pipe corrosion.
 

 

• Select aftercoolers, separators, dryers and filters having the lowest possible pressure drop for the rated conditions.
 

 

• Reduce the distance the air travels through the distribution system.
 

 

• Specify pressure regulators, lubricators, hoses, and connections having the best performance characteristics at the lowest pressure differential. These components must be sized based upon the actual rate of flow and not the average rate of flow.