Posts Tagged ‘compressed air’

  • ­­­Does your air pressure keep dropping while you are using your tools & equipment?
  • Have you added or are planning to add new equipment which uses air?
  • Are your air compressors working hard all the time- but you just aren’t sure how to figure how much more horsepower you need?

When your business counts on air – you need to know the valuable formulas and steps to help accurately determine how many CFM you use. You also need to know how to accurately figure how much additional CFM and horsepower you need when considering a new air compressor?

Here are some specific formulas that can help you determine how many CFM you presently use and how many more CFM you need to meet your desired PSIG. We will show you how to take this information and use it to determine how much air compressor horsepower you actually need.

Find out how many CFM your air compressor delivers

1. STOP the compressor unit

2. CLOSE the outlet valve on the tank/air receiver

3. DRAIN the condensate from air receiver until there is 0 PSIG –
then close the drain valve

4. NOTE THE TIME- in minutes & seconds (Best to write it down.) Then START THE UNIT.
When the compressor unit stops and unloads – then NOTE THE TIME again – in minutes & seconds. Convert the minutes into seconds and then total the number of seconds it takes between START and STOP/UNLOAD.

5. NOTE the GUAGE PSIG reading

6. NOTE the Air Receiver/Tank GALLON SIZE

7. USE THIS FORMULA:

TANK GALLONS x .538* x PSIG divided by SECONDS

EXAMPLE:

You have an 80 gallon tank, your total start to stop/unload time was
3 minutes and 30 seconds. Change the minutes to seconds timed
(60 x 3= 180 seconds plus 30 seconds which totals 210). You will use the total number of seconds (210) and the noted 175 PSIG within the formula as shown below:

80 multiplied by .536 = 42.88
42.88 multiplied by 175 (Example PSIG) = 7504.00
7504.00 divided by 210 (total seconds)= 35.74 CFM delivered

The example shows that the air compressor is delivering 35.74 cfm

Your Response to this evaluation should be to compare this number with what your air compressor manufacturer says your CFM should be and evaluate how efficiently your compressor is running.
If your air compressor is within 10% of manufacturer’s specifications, then the unit is OK, if not – repair unit and recalculate your needs.

Find out how many more CFM you need to
raise your PSIG

1 What is your desired pressure ______?
(Our Example125 psig)

2. What is your present operating pressure_______?
(Our Example 70 psig)

3. Divide desired pressure by present operating pressure
(125 psig divided by 70 psig = 1.79)

4. This gives us the X-factor needed for this formula (1.79 )

Multiply present air compressor cfm (35.74) by your X-factor (1.79)
(35.74 X 1.79= 63.98 This gives you the total cfm needed –
which is 63.98 for our example)

6. Deduct your present cfm from the needed cfm
(63.98 minus 35.74 present cfm = 28.24)

7. This gives you the additional cfm needed to raise your psig to the level you actually need. (which is 28.24 additional cfm for our example)

Translate your answers into how much horsepower
you actually need to operate

Divide your additional cfm needed by 3.5* (see the chart for your *actual compressor type & horsepower)
(28.24 ÷ 3.5 = 8.07 hp, which would be the additional horsepower needed for our example)

This will give you the additional horsepower you actually need.

(We will need to round up the 8.07 hp to 10 hp needed for our example. You will have to round up to the nearest standard
horsepower also.)

*CFM per compressor horsepower chart:

3.5.cfm per hp for small piston compressors ½-30 hp

4 cfm per hp for large piston 40 hp up & small screw compressors
2 hp-30 hp

4.5 cfm per hp for 40 hp-150 hp medium hp screws

5 cfm per hp for 200 hp-2000 hp large screw & centrifugal compressors
Note: Always buy CFM of delivered air at the PSIG you need…not horsepower.

Note: Always invest in at least 20% more CFM than your equipment needs. This will cover extra air usage for such things as air leaks and wear.

Follow these formulas and you can figure just how much more CFM and air compressor horsepower you really need to get the job done!

Compressor Terms you should know:

Cubic Feet Per Minute (cfm) – Volumetric air flow rate.

“psig” means pounds per square inch, GAGE pressure. Gage pressure is the absolute pressure of something, with the atmospheric pressure subtracted. In practice, when someone gives a pressure in just “psi” they probably mean gage pressure. If they mean absolute, they should be using “psia.”

Gauge Pressure – The pressure determined by most instruments and gauges, usually expressed in psig. Barometric pressure must be considered to obtain true or absolute pressure.

Load Time – Time period from when a compressor loads until it unloads.

Unload – (No load) Compressor operation in which no air is delivered due to the intake being closed or modified not to allow inlet air to be trapped.

Receiver – A vessel or tank used for storage of gas under pressure. In a large compressed air system there may be primary and secondary receivers.

Tommy McGuire

McGuire Air Compressors, Inc.
“Real People with Real Compressor Experience”

1-888-229-9999

www.industrialaircompressors.biz

www.hosereels.biz

www.airdryers.biz

The most used, most needed and most valuable Compressed Air Formulas

Do you have access to the most used, most needed and most valuable Compressed Air Formulas? Here’s one of the most used formulas you should keep on hand…
How to find how many CFM your air compressor delivers.

Follow these steps to find out how many
CFM Your Air Compressor actually delivers

1. STOP the compressor unit

2. CLOSE the outlet valve on the tank/air receiver

3. DRAIN the condensate from air receiver until there is 0 PSIG -then close the drain valve

4. NOTE THE TIME– in minutes & seconds (Best to write it down.) Then START THE UNIT.
When the compressor unit stops and unloads – then NOTE THE TIME again – in minutes & seconds. Convert the minutes into seconds and then total the number of seconds it takes between START and STOP/UNLOAD.

5. NOTE the GUAGE PSIG reading

6. NOTE the Air Receiver/Tank GALLON SIZE

7. USE THIS FORMULA:

TANK GALLONS x .536* x PSIG divided by SECONDS

*.536 is a formula factor for the unknown that works to give you the CFM delivery.

EXAMPLE:
You have an 80 gallon tank, your total start to stop/unload time was 3 minutes and 9 seconds.
Change the minutes to seconds timed (60 x 3= 180 seconds plus 9 seconds totals 189).  You will use the total number of seconds189 and the noted 175 PSIG within the formula as shown below:

80 multiplied by .536 = 42.88
42.88 multiplied by 175 (example PSIG) = 7504.00
7504.00 divided by 189 (total seconds)= 39.71 CFM delivered

You now know that your air compressor is delivering 39.71 CFM

Your Response to this evaluation should be to compare this number with what your air compressor manufacturer says your CFM should be and evaluate how efficiently your compressor is running.

 

Compressor Terms you should know:

Cubic Feet Per Minute (cfm) – Volumetric air flow rate.

“psig” means pounds per square inch, GAGE pressure. Gage pressure is the absolute pressure of something, with the atmospheric pressure subtracted. In practice, when someone gives a pressure in just “psi” they probably mean gage pressure. If they mean absolute, they should be using “psia.”

Gauge Pressure – The pressure determined by most instruments and gauges, usually expressed in psig. Barometric pressure must be considered to obtain true or absolute pressure

Load Time – Time period from when a compressor loads until it unloads.

Unload – (No load) Compressor operation in which no air is delivered due to the intake being closed or modified not to allow inlet air to be trapped.

Receiver – A vessel or tank used for storage of gas under pressure. In a large compressed air system there may be primary and secondary receivers.

Demand – Flow of air at specific conditions required at a point or by the overall facility.

Tommy McGuire

McGuire Air Compressors, Inc.
“Real People with Real Compressor Experience”

1-888-229-9999

www.industrialaircompressors.biz
www.hosereels.biz
www.airdryers.biz

 

 

Key #1: PREVENTIVE MAINTENANCE
“What is the key to maintaining an efficient compressed air system?” The best reply would have to be — Preventive Maintenance.
WHAT IS PREVENTIVE MAINTENANCE?
According to “Wikipedia”: Preventive maintenance (PM) has the following meanings:
“The care and servicing by personnel for the purpose of maintaining equipment and facilities in satisfactory operating condition by providing for systematic inspection, detection, and correction of incipient failures either before they occur or before they develop into major defects. Maintenance, including tests, measurements, adjustments, and parts replacement, performed specifically to prevent faults from occurring.”

*Source: from Federal Standard 1037C and from MIL-STD-188 and from the Department of Defense Dictionary of Military and Associated Terms
Preventive maintenance activities include partial or complete overhauls at specified periods, oil changes, lubrication and so on. In addition, workers can record equipment information and deterioration so they know to replace or repair worn parts before they cause system failure.

The ideal preventive maintenance program would prevent all equipment failure before it occurs.

BENEFITS OF PREVENTIVE MAINTENANCE:
-Improves system reliability and helps keep equipment working and/or extend the life of the equipment.
-Decreases system downtime and actively helps prevent unbudgeted maintenance expenses from cropping up.
-Decreases the cost of having to replace equipment as often.
-Records operational data that can help you troubleshoot an emerging problem (called “Data Trending”)
Data trending is the recording of basic operation parameters including pressures, temperatures, and electrical data. For example, a slowly increasing temperature indicates a variety of maintenance requirements including cooler core cleaning, overloading of system and possible mechanical problems. Another example might include slowly decreasing pressure, indicating increased system flow requirements, reduced compressor performance or increased system leakage. Make sure someone is looking at this data on a regular basis. If the data is never reviewed then the benefit is lost.

THE VALUE OF PREVENTIVE MAINTENANCE:
To determine how valuable regular air compressor PM is to you and your business… you need to know what your “down-time” is worth. In some operations, down-time can cost hundreds, even thousands of dollars an hour.
There are many misconceptions about preventive maintenance…one being that it costs too much.

This line of thinking says regularly scheduled downtime for maintenance costs more than operating the equipment until repair is absolutely necessary…or until the equipment breaks. This may be true for some components, but don’t forget to consider the long-term benefits and savings associated with preventive maintenance that have been previously mentioned.

If regular Preventive Maintenance can help reduce unexpected downtime that results in loss of production, time and materials or the ruining of an expensive plant process–then it is well worth the investment. Not to mention that unscheduled shut-downs can be extended if the correct equipment parts or repair technicians are not readily available.

“How effective is your PM program?”
The answer is: “If your PM program isn’t finding problems, it isn’t effective.”

Key #2: CORRECTIVE MAINTENANCE
Corrective maintenance, usually called “repair”, is conducted to get equipment working again or fix any problems found during Preventive Maintenance.
The primary goal of maintenance is to avoid or reduce the consequences of failure of your compressed air equipment. PM is designed to preserve and restore equipment reliability by replacing worn components before they actually fail.

Key #3: ASSESSING YOUR EQUIPMENT: When to maintain and when to replace.
Here are several factors to consider when assessing your compressed air equipment:
-How critical is your compressed air equipment? If equipment fails, what is the impact on production or safety.
-What is the age & history of your equipment.
Equipment histories will prove that most failures occur during infancy (newly installed or recently overhauled) and old-age (self-explanatory).
How many times has this equipment failed in the past?
-How much do you trust this equipment to perform as designed when scheduled to run?
-Do you need newer technology on your equipment?
Assessing the answers to these questions will help you determine when your older equipment needs fixing or replacing. Preventive Maintenance will help your equipment last longer, run better, and save you loads of money in the long haul.

Key #4: KNOWING YOUR EQUIPMENT WHAT IT NEEDS:
-Every piece of compressed air equipment should come with a set of MAINTENANCE INSTRUCTIONS and some type of operations& parts manual. Your operators should review the equipment information and keep it handy for future reference. If you purchased used equipment and don’t have the manuals, contact your equipment distributor for a copy.
– Follow the maintenance guidelines for your equipment.

Ask a Question:
Can water or moisture be damaging my compressed air system?

Answer:
Absolutely! Water corrodes pipes, valves, machinery controls. None of this is good.
When controls malfunction, production can stop or product can be impaired and all this costs you time and money. Water in Aerosol or Vapor form is more difficult to remove and requires the use of a Compressed Air Dryer.

Ask a Question:
How does water or moisture get into my compressed air?

Answer:
Through your Compressor inlet.
Water vapor (humidity-moisture) enters the air system through the air compressor inlet air filter. The air compressor sucks in approximately 7 cubic feet of atmospheric air at 0 psig, and that volume of air is compressed into 1 cubic feet of air at 100 psig. The water vapor (humidity-moisture) that was in the 7 cubic feet of atmospheric air is now compressed into 1 cubic feet of compressed air.

There are 3 forms of water in compressed air:
Liquid water
Aerosol (mist)
Vapor (gas)
Any of these forms of moisture can create problems down the road in equipment or may create serious problems in your process or end product today.

Ask a Question:
How to tell if you need a Refrigerated Air Dryer?

Answer:
If you are experiencing the following problems…then you may need a Refrigerated Compressed Air Dryer:
Liquid water is in your air lines and hoses
Water vapor sprays out of your tool exhaust
Pipe lines corrode and rust
Paint Sprayer has water spots in the paint
Your Equipment Manufacturer specifies “DRY AIR”

Ask a Question:
What can help remove moisture from my Compressed Air System?

Answer:
Refrigerated Air Dryers can be one of the best solutions to removing water and moisture from youCompressed Air System.

Ask a Question:
How does a Refrigerated Air Dryer Work?

Answer:
• The refrigerated air dryer cools the incoming compressed air first in an air-to-air heat exchanger where the outgoing cool dry air pre-cools the hot incoming air and condenses some moisture out.

• Then the incoming air enters an air-to-refrigerant heat exchanger where the air is cooled to 38º F by the liquid refrigerant. This process causes the moisture to condense into liquid water and it is drained away. The out going air then enters the air-to-air heat exchanger and is warmed up to keep the outside of pipes from sweating.

• The refrigeration compressor pumps hot hi-pressure gas refrigerant (Freon) into the condenser which transfers the heat from the refrigerant gas to the ambient air as the gas condenses into a liquid.

• The liquid refrigerant (Freon) is then metered to a cold low pressure where it enters the air-to-refrigerant heat exchanger and the heat from the hot compressed air is adsorbed into the cold refrigerant (Freon). The refrigeration compressor then sucks low pressure hot gas refrigerant (Freon) into the refrigeration compressor and the cycle starts over again.

BOTTOM LINE:
If you are experiencing unwanted moisture and water in your Compressed Air System, then seriously consider the addition of a Refrigerated Air Dryer. After all – what is the best way to spend your money –on constant maintenance, failed equipment and ruined end products or by investing in a properly sized compressed air dryer?

Experience proves it! Remove Water and Moisture to improve Compressed Air Quality & Efficiency!

Increase Production – less down time due to moisture related equipment problems
Reduce loss due to inferior products ruined by moisture in lines
Bring more profit to your bottom line


Learn More about Refrigerated Air Dryers www.airdryers.biz

1-888-229-9999
Owned & Operated by
Tommy McGuire
McGuire Air Compressors, Inc.
“Real People with Real Air Compressor Experience”
P.O. Box 1100
Graham NC 27253

Learn more about Industrial Air Compressors www.industrialaircompressors.biz

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