FAQs
In what states does Scales Industrial Technologies do business?
Our repair and warehouse centers are located in Pennsylvania, New Jersey, New York, Connecticut and Massachusetts servicing these states as well as Maryland, New Hampshire, Vermont and Rhode Island. In addition we have national accounts that we service in almost every state in the United States and a number of clients we take care of internationally.
How can Scales Industrial Technologies help me save energy?
Read the some of the most common questions found here, look at the education and reference section on our website and contact the nearest Scales location for answers to your specific compressed air system. Literally, we wrote the book!
What are my true costs of compressed air?
The most significant cost is the cost of energy. Other components include drying, filtering, maintenance and the capital cost for purchasing the equipment. The total cost of compressed air has been calculated to be in the range of 18 – 32 cents per 1000 cubic feet (source: Best Practices for Compressed Air Systems).
How much can a Scales Energy Assessment save me?
It depends, but savings of 20% are usually the minimum, 30% is a good average, and some savings have been 70% or greater! Download a technical paper from our education section to see what others have done.
What is a $mart Sequencer?
A $mart Sequencer is a patented compressor system controller that will reduce your plants energy costs by continuously monitoring system demand and automatically selecting the most energy efficient combination of available compressors to meet your plant’s compressed air requirements.
How does it differ from a common multiple compressor controllers?
Most multiple compressor controllers control multiple compressors based on a pressure signal, starting and stopping based on preset pressure and a preset order of machines. The $mart Sequencer automatically selects the most efficient mix of compressors based on system requirements.
Can the $mart Sequencer control different makes and types of air compressors?
Absolutely! The $mart Sequencer can control any type and make of air compressor as well monitor and control dryers, pressure, cooling water temperatures, ambient air temperature and more.
Why can part load operation of my air compressors result in significant energy waste?
Compressors operating at part load can waste a significant amount of energy. For example; a compressor with modulation control or a load/no load compressor with little storage can use as much as 85% of full load power at 50% load, a waste of 35% of the input power.
What about Variable Speed Drives or Variable Displacement control?
Variable speed drives vary the speed of the drive motor thereby speeding up or slowing down the compressor to match supply with demand. Variable displacement control varies the size of the compression chamber therefore the capacity and again more closely matching supply with demand. Both types of control are excellent if applied properly.
Please contact your local Scales Industrial Technologies expert for help in improving your compressed air energy efficiency.
What is the difference between cfm, acfm and scfm?
cfm: the amount of air flow delivered under specific conditions, usually expressed in cubic feet per minute.
acfm: (actual cubic feet per minute) flow rate of air at a certain point at a certain condition at that point.
scfm: (standard cubic feet per minute) flow of free air measured and converted to a standard set of reference conditions (14.5 psia, 68°F, and 0% RH).
What is the best way to find leaks?
Generally the production people know exactly where the leaks are and a good program is to include them in the hunt and to fix them promptly. Many plants can hear the leaks particularly on a walk-through when the plant is quiet, oothers will use an ultrasonic leak detector or hire an expert to identify the source.
Scales Industrial Technologies uses ultrasonic leak detection and will identify, tag and fix leaks.
How do I determine my leak load?
For systems that use load/unload controls as well as start stop control it is relatively easy to estimate the leak load in a system. Start the compressor when there are no demands on the system and time the load and unload cycles several times to get an average. Now apply the following formula: Leak percent =
T x 100
(T + t)
Where: T = time full load and t = time fully unloaded or off for start stop systems. For systems with modulated control the leak load can be estimated using monitored kW data or measured using a mass flowmeter. Call your local Scales location for further assistance.
How does raising or lowering pressure affect my energy costs?
A rule of thumb for nominal 100 psig systems is for every 2 psi the resultant energy change is 1%. So if you lower your system pressure by 10 psi the change in energy at the compressor should be 5%. Try it and use a simple clamp-on ammeter to measure the results.
Let us know the data and your energy rate and we will help you determine the cost differential. Additionally, operating at a lower pressure reduces leakage rates and air usage in unregulated devices which may provide an additional energy savings benefit.
How do I determine what pressure I really need?
The end use equipment manufacturer’s requirements may have a built-in safety margin to ensure satisfactory and efficient operation. The manufacturer of the equipment should be asked what the effect of lower pressure would be. For existing systems, the actual pressure at each use point should be checked with the tool or machine operating and compared with the manufacturer’s stated minimum requirement.
What size pipe do I use?
Determine what your total system flow is and use the chart or calculator found in our education and reference section.
What type of pipe material should I use?
Cost is almost always a factor in the selection of piping material for a compressed air system, generally a corrosion resistant material such as copper, galvanized, stainless steel pipe or the new aluminum piping systems is preferred more than common black iron pipe. PVC pipe is NEVER an option unless specifically labeled and supplied for compressed air use. The pipe selected must be compatible with the plants atmosphere and pressure requirements. Consult, federal, state and local codes before deciding on the type of piping to be used.
Scales Industrial Technologies can also help you with your selection, please call your local location. In addition, please see the section on piping systems under Equipment for information on the newest aluminum piping systems.
Should I have a loop in my plant piping or would a straight pipe run work too?
Generally a loop type header with drops to each point of use is best. This design helps to feed distant use points of from both directions and is self-balancing.
What is the difference between oil-free and oil-less air compressors?
The terms are frequently intermixed but both refer to the absence of oil in the compressor chamber. More specifically oil-less compressors are compressors that do not contain oil anywhere in the compressor pump or crankcase.
Oil-free compressors do not have any oil in the compression cylinder but use lubricant in the crankcase. In reciprocating compressors the oil is usually separated from the compression chamber by rings and distance pieces. Oil-free rotary compressors and centrifugals have a separate lubrication system which uses seals and vents to keep the oil separate from the compressed air.
What size receiver should my system have?
The old rule of thumb of 1-2 gallon of storage for the trim compressor is no longer valid. The new rule of thumb suggests 3 – 5 gallons of storage for most systems (based on the capacity of the trim compressor(s)). Size requirements can also vary by the type of compressor, the type of compressor capacity control, and the quantity and duration of transient demand events and the time interval between them.
Call Scales Industrial Technologies for expert help in sizing air receivers.
Do I really need a pressure/flow controller and does it really work?
A pressure/flow controller when properly designed, applied and installed can maintain system pressure to ±1 psi. Determine the current and maximum tolerable pressure variation for your system and decide if the pressure flow controller meets your specific cost benefit ratio. Sometime an oversized regulator or pilot operated regulator can meet your needs.
Call your Scales Industrial Technologies specialist for more information.
What are the compressed air quality classes?
Compressed air quality classes to ISO 8573-1
| Class | |||||
| 1 | 2 | 3 | 4 | 5 | |
| 0,1 | 1 | 5 | 15 | 40 | Solid particles: particle size in μ |
| -70 | -40 | -20 | +3 | +7 | Dew point in °C |
| 0,01 | 0,1 | 1 | 5 | 25 | Oil quality (max. concentration in mg/m3) |
The quality class is specified by means of a sequence of 3 figures.
For example: class 141 = solid particles 0.1μ (class 1) / dew point +3 (class 4) / oil quality 0.01 mg/m³ (class 1)
What quality of air is needed for instrument air?
The Instrument Society of America definition of “Instrument Quality” Air is:
A maximum oil content of less than one part per million (by weight);
The particle size in the air stream must be less than 40 microns; and
The dew point must be 18ºF below the minimum temperature to which the air is exposed
What air quality do I need for my application?
| Shop air | Usually moisture separation with some filtration. |
| Air Tools, Air Operated Machines, Sand Blasting, Pneumatic Controls | Refrigerated air dryer, oil and moisture removal and particulate removal to 1 micron. |
| Paint Spraying, powder coating. | Refrigerated air dryer, oil removal to .01 mg/m3 particulate removal to .01 micron. |
| Instrument air and air used outdoors | See Above. Regenerative desiccant type dryer, oil removal to .01 mg/m3, particulate removal to .01 micron. |
| Pharmaceutical | Oil-free air supply, regenerative desiccant dryer, fine particulate filtration, vapor adsorber filter. |
| Breathing air system | Breathing air purifier system |
Do I need a filter before or after a refrigerated dryer and what type works best?
It is suggested that a pre-filter for particulate and water separation be installed before the dryer to keep the heat exchangers clean and a coalescing type oil removal be placed after the dryer to further clean the air of smaller particulate and remove oil aerosols.
What are some potentially inappropriate uses and what are the alternatives?
Open blowing: using compressed air with an open, unregulated tube, hose, or pipe for cooling, cabinet cooling, parts ejection, conveyor clearing. Blowers and fans are very good alternatives to a lot of open bowing applications.
Sparging: aerating, agitating, oxygenating, or percolating liquid with compressed air. Blowers are an excellent alternative for these applications.
Aspirating: using compressed air to induce the flow of another gas with compressed air such as flue gas. Again blowers or fans are an excellent alternative.
Atomizing: using compressed air to disperse or deliver a liquid to a process as an aerosol. An example is atomizing fuel into a boiler or atomizing water for parts cleaning. Again blowers or fans are an excellent alternative.
Open drains: Open drains are open tubes or pipes used to drain liquids from filters and dryers. Zero loss air drains are an excellent alternative to open drains.
Please contact your local Scales Industrial Technologies expert for help in improving your compressed air energy efficiency.
If I have a vacuum leak, how can I find it?
An ultrasonic leak detector is one of the best ways to find a vacuum leak.
How is vacuum usually measured and what is a Torr, Micron, mm HG?
One standard atmosphere at standard conditions will support a column of mercury 29.92" high. This is where the linear measurement in vacuum comes into play. 29.92" can be also measured in mm Hg (760mm = 29.92") and microns (760,000 microns = 760 mm = 29.92").
What is the difference between SCFM & ACFM as it pertains to vacuum?
SCFM stands for Standard Cubic Feet per Minute. SCFM is the air volume measured at “standard conditions” which refers to atmospheric pressure (760 m Hg), at sea level elevation and a temperature of 60 Deg F. ACFM stands for Actual Cubic Feet per Minute and represents air volume pumped at the pressure, elevation and temperature your particular system is operating at. Many vacuum pump performance curves shows ACFM to indicate the actual volume of process gas pumped at various inlet pressures to the pump.
What is the best vacuum pump for my application?
There is no one vacuum pump that is fits all applications. However, there are some general guidelines to remember for your selection.
Oil Lubricated Rotary Screw Vacuum Pumps are used in applications requiring fairly deep vacuum and pumping relatively clean gases. Hospital applications are excellent for rotary screw vacuum pumps.
Dry Vane pumps are used when a pump is required that does not require lubricating oil because of the objection to oil vapor discharge from the pump and filling/disposal issues with oil. Rotary vane dry pumps however are capable of only maximum vacuum of approximately 25" Hg and can only pump clean DRY air. Any presence of moisture in the gas being pumped can lead to the pump failing because of the absence of lube oil.
Rotary Screw Dry Pumps are used in applications where a high vacuum is required (up to 0 .010 mm Hg) and the process gas is not compatible with lubricating oil in oil sealed rotary pumps. These pumps are fairly expensive and are used where a lubricated oil sealed pump or liquid ring pump is not desired.
Liquid Ring Pumps are used in applications where the process gas may contain a sizable amount of condensable vapors (water, solvents, acids, etc.) that will react negatively with the lubricating oil in Rotary Vane pumps, thereby causing pump damage. Liquid ring pumps are relatively inexpensive and can use any sealing fluid (water, oil, ethylene glycol, solvents, etc.) that is compatible with the process. Please contact your local Scales Industrial Technologies expert for help with your vacuum requirements.