Hycomp Performance Under Pressure™

Volumetric flow measurements can be confusing and some equipment manufacturers tend to be a little vague in order to reflect positively on the performance of their equipment. The first reason for the confusion is the simple fact that gases are compressible. As such, variations in pressure, temperature, and humidity significantly change the volume and density properties of the gas. Additionally there are many variations in the “standard” definitions for the different flow rate measurements. It can all seem pretty confusing.

Standard Cubic Feet per Minute (SCFM) is used as a common reference for flow rate performance. However, there are at least 13 recognized variations to the “standard” conditions, published by agencies like CAGI, NIST, ANSI, ISO, EPA, U.S. Army, etc. At Hycomp, we primarily use the standard conditions of Pressure (14.696 psia) and , Temperature (60 F). SCFM is used mostly as a common reference point for comparing the performance of different pieces of equipment.

Actual Cubic Feet per Minute (ACFM) is used to express the volumetric flow based on defined pressure and temperature conditions at the location in the system where the measurement is being taken. ACFM could reflect the flow at the inlet to a compressor. ACFM could reflect the flow at the discharge of an air booster. ACFM could reflect the flow at the point of use of plastic bottle blowing equipment. It all depends on what is defined. It is important not to confuse ACFM with atmospheric conditions at the site, although since this could be part of the “system”, ACFM and atmospheric conditions could be same.

Inlet Cubic Feet per Minute (ICFM) is used to express the volumetric flow based on the actual pressure and temperature conditions at the inlet to the equipment. ICFM and ACFM at inlet conditions are, of course, identical. Sometimes ICFM is used interchangeably with the term Free Air Delivery (FAD).

The generic term, Cubic Feet per Minute (CFM), is used at times by manufacturers, but it is inherently misleading since it is not tied to any frame of reference.

With all of these units of measure, the most critical step to understanding them well is to be sure that the definitions and the standard conditions being referenced by all equipment manufacturers and users are matching up with each other. Without that, you are literally comparing apples to bananas. There are plenty of resources on the internet that can help with definitions of standards and making conversion calculations so that the comparisons are valid. Proper understanding and use of common definitions will certainly help eliminate confusion.

A few general rules to apply are:
1. Spend some time with equipment providers and equipment users to be sure that everyone is using the same standard definitions.
2. In general, use SCFM to compare equipment capacities
3. In general, use ACFM to make calculations regarding actual conditions and equipment loading.
4. Always consider the worst case site and/or system conditions as part of the calculations.
5. Call Hycomp and arrange an E2E discussion to sort it all out.

 
Mike Byrd of Air Services Company recently had a complex booster application for PET plastic bottle blowing that he was working on with his customer. The system involved multiple equipment providers. The customer was having trouble getting clear information regarding flow requirements and specifications. During an Engineering to Engineer (E2E) discussion with the end user, all the parties were able to clarify the flow measurement information by settling on the same standard definitions as a common baseline. A consensus was reached quickly and the right solution was proposed.

After that E2E discussion, Mike reported back to Hycomp:

”I just want to let you know how well the E2E conversation we had last week went. Shortly after our conversation ended, I received a phone call from my customer thanking me for taking the time to speak with them. Their high level management personnel all had questions that they needed answered so they could make a more educated decision on their equipment purchase.”

Mike concluded, “By the end of the conversation we all had a much better understanding of compressed air boosters, flow ratings, the customer’s process and the Hycomp solution. I am confident that this conversation “boosted” our odds at getting an order and gave the customer more confidence in the Hycomp product. Thanks for your help.”

Mike was right, 7 days later, the customer issued a purchase order for a Hycomp Oil Free Air Booster.

Proper installation has a direct relationship with the operation and longevity of a compressor. When an installation is done right, the compressor is mounted to a secure foundation to minimize vibration and ensure correct operation.

When installation is performed incorrectly the compressor may experience operational problems that can lead to significant maintenance issues and unwanted downtime. The three most important factors when building a foundation for your Hycomp compressor are: Location, Foundation Construction and Pre Installation Technical Advice.

Location:
Many factors must be considered for optimal compressor location. Locate the compressor in a dry, well ventilated and well lit area that accommodates inspection and maintenance access. An unobstructed machine boundary of at least 18” must be arranged to provide adequate air flow and service space around the compressor.

Installation in locations exposed to ambient subfreezing temperatures is not recommended. Exposure to direct sunlight, rain, wind, dust, snow, moisture, and other adverse environmental elements is not recommended and will reduce service life and increase maintenance requirements. If it is necessary to install the unit out of doors, provide a rain cover or a completely enclosed shed to prevent corrosion. If the installation location will experience operating temperatures below 32°F, a properly sized crankcase heater must be installed.

Rotating machinery should always display appropriate restrictive warnings and cautions to minimize risk of injury to personnel. Even though Hycomp compressors are not as loud as other pumps, rotating machinery does produce noise. Understand your service environment and prepare accordingly.

Foundation Construction:
Proper foundation construction ensures smooth operation, reduces vibration and can extend the life of your compressor. Todd McGregor, Hycomp Service Manager, has performed many factory startups, and seen differing levels of installation quality. He explains a few things to look when building on an existing foundation, “For installation on an existing floor - Check the floor plan and establish how the floor was constructed, for example: concrete aggregate/psi, how thick is the floor, how well was the floor reinforced and how old is the foundation. Based on these facts - get expert advice for what will work best for your situation.”

Robert James, Hycomp President and Engineering Manager, understands that a new foundation may not always be possible, “In existing floors, a Drillco Maxi-Bolt is a good choice, as it actually utilizes a special undercut hole which allows the anchoring to be rock solid.”

When building a new foundation it is important to not cut corners and utilize the following parameters. The foundation should rest on solid bedrock or compacted earth or gravel, but not a combination of the two. The pad should be composed of 4,000 psi cured concrete reinforced with ASTM A615 #4 billet steel re-bar cross laced on 16” centers located 3” above the base.

The amount of concrete used to form the pad should exceed the weight of the compressor by 3 to 5 times. SAE Grade 5 “J” bolting of appropriate length and size should be used in the pad to provide baseplate mounting. Use of a template to support and position the bolting +/– 1/16” while setting concrete is recommended. Securing bolting to existing foundations with drilled holes and adhesives is not recommended unless expert advice is available. Expert advice is also recommended for installation of other forms of mechanical anchors. Call Hycomp if you are unsure what size to use or for technical advice on different anchors.

McGregor instructs further on compressor mounting and shimming, “Installers need to utilize all skid mounting holes intended for anchoring. Compressors must be level. Use shims as needed. Shimming of skids (on concrete and steel foundations) may be required to prevent excessive vibration. Steel fabricated foundations must be adequately engineered to support the weight and vibration of the compressor.”

Epoxy based grouting is required to firmly seat and attach the compressor skid to the concrete foundation for newly constructed or existing foundations. ITW Philadelphia Resins brand “Chockfast Red” grout is recommended. “I think there are a few general pieces of advice that should be considered for grouting of fabricated channel skids, such as: do not fill it up to the point that one cannot access the compressor or motor mount bolting, drill for drain holes if located out of doors, plumb oil drain to skid edge, etc.,” said McGregor.

Sealing of grouts and concrete is recommended to prevent contamination by oil and moisture. The concrete slab should be chipped to expose 50% of the aggregate andv to provide a rough bonding surface for the epoxy. Dowels should be installed on new exposed concrete to prevent edge lifting. The concrete foundation should be dry and free of oil before pouring grout. Sleeve all foundation bolts to prevent adhesion and allow bolt stretch. Steel baseplates should be sanded and cleaned to provide adequate adhesion surface.

Pre Installation Technical Advice:
Unlimited tech advice and support is included at no additional charge with every Hycomp compressor. Hycomp technicians are available to assist you 24 hours a day. Hycomp technicians like Todd McGregor are ready to answer your question, “Our customers can call 24 hours a day, 7 days a week and 365 days a year. We will do our best to get them the answers they need so their Hycomp equipment is operating in a correct manner.”