Industrial Utility Efficiency    

Food Industry Expertise at Parker domnick hunter

Good morning. What’s new at Parker domnick hunter (dh)?

Good morning. We recently announced the formation of the new Parker PDF (Purification, Dehydration, Filtration) Division. This new Division merges Parker domnick hunter North America with Parker Airtek and creates one Compressed Air & Gas Purification team to serve the North American market.

The responsibility of the Parker PDF Division is to further develop our market-leading brands of domnick hunter, Zander, and Airtek. From a technology standpoint, we believe that the new division offers the most comprehensive and diversified product portfolio in the compressed air and gas purification market.

Please describe the market you serve.

Compressed air is often called “the 4th utility.” When factories want electrical power, they just plug in. With compressed air, the facility has to specify, install, manage, and maintain the utility. In order for compressed air to be a useable, efficient, and productive energy source, the responsibility falls upon the shoulders of each individual plant. This makes compressed air a unique “utility”.

Compressed air purification, dehydration, and filtration determines the quality of this power source. It also can determine the efficiency of this utility. This is the market we serve. The Parker PDF Division provides the education and technologies required to use compressed air productively and efficiently.

Why is compressed air purification necessary for every compressed air system?

Compressed air contaminants can cause disruptions (product spoilage, downtime) to manufacturing operations and create elevated energy costs to run the system. Most people think of just water, dirt, and oil when they consider compressed air contaminants. There are actually ten (10) different contaminant types and it is our primary focus to help operations understand them and take actions to eliminate them. Our focus is on preventing disruptions to plant operations by ensuring the supply of high quality compressed air. We manufacture equipment capable of handling all contaminants and just as important – our engineers council plant personnel on how to apply the technologies effectively.

Should there be a compressed air quality specification written for the U.S. food industry - similar to what the BCAS has done? ÜIf so, does the industry have any plans to do this?

There absolutely should be a specification for the food industry in the U.S.. When we go to food plants, each system is different and the system design is driven by a compressor distributor working on their own. Most systems have a high potential for contamination. We often see water and oil dripping out of the compressed air lines at the packaging machines. Look at some of the outbreaks recently (like the peanut butter facility in Georgia). Every major country has legislation which forces the producer to look at food hygiene. All require the use of the HASAP principle. The guy doing the risk assessment, however, sees compressed air as a utility. They don’t see the contaminants or understand them. They have a duty to protect the consumer but it’s not being done in many instances. The pipe has 10 contaminants but in this country you can’t go to college and learn about compressed air. There is a 3A Standards Committee for the food industry. They have a very generic compressed air specification and we have approached them to discuss the topic.

Other than that, we are not aware of any current plans to develop a compressed air specification for the food industry in the U.S. We would welcome this development and would assist in any way we can. Currently, we typically use the Code of Practice jointly developed by the British Retail Consortium and the British Compressed Air Society as the “next best thing”.

What are some of the issues you see in the food industry?

The most common issue is that a high percentage of installations (where compressed air comes into contact with food products) use refrigerated dryers capable by design of only a 38 F (3 C) pressure dew point. In order to inhibit the growth of microorganisms and fungus, pressure dew point must be below -15 F (– 26 C). For this reason we always recommend a desiccant dryer which can provide a -40 F pressure dew point.

One of the major contaminants of concern to the food industry is microorganisms. The moisture in compressed air creates an ideal habitat for harmful microorganisms and fungi. When the compressed air is dried below -15 F, they are converted into a spore. These spores are then filtered by our filtration technologies.

How important is the compressor type to air quality?

A common misperception exists around the use of oil-free air compressors. We have visited facilities with oil-free air compressors installed and absolutely no filters and dryers. An oil-free air compressor alone is not a solution. You have removed only one of the ten contaminants-the oil aerosol. No matter what the air compressor technology is, the air treatment requirements do not change.

No matter what type of air compressor is installed, they all draw in large volumes of airborne contamination and therefore the level of compressed air purification equipment required in a compressed air system is not dependent upon the type of compressor installed. Adequate filtration and separation products will always be required to remove the large volume of dirty contaminated water as well as dirt, pipe-scale and microbiological contamination.

Air treatment requirements (for the food industry) do not depend upon the air compressor, rather they depend upon the application of the compressed air. It is critical to understand whether the system design and the role for compressed air – in order to define the purification methods needed. We break it down into three system designs; Contact, Non-Contact, and Non-Contact


How can end users use the ISO 8573.1 Standard?

The ISO 8573.1 Standard is designed to help operators of compressed air systems specify their purity requirements. By using this standard, a factory can be very specific to the prospective vendors as to what they want.

This Standard also creates awareness of purity requirements. This opens the opportunity to define purity requirements in different “zones” of the factory. In the past, all the compressed air purification was done in the compressor room and the factory lived with one purity requirement/specification. It was common to see huge pressure-swing desiccant dryers in the compressor rooms delivering -40 F pressure dew point air quality to the whole factory. The downside to this is that often only 10% of the compressed air volume needed this level of air quality. The unnecessary energy-costs to the factory were very large.

Today we recommend that plants use the ISO 8573.1:2001 Standard to define what air quality is needed in what section of the factory. In this way, the above example could have used a desiccant dryer for 10% of the air load and a refrigerated air dryer for 90% of the air load. The benefits in energy savings and maintenance costs would be significant to the factory.

Please note that ISO 8573.1:2001 is the latest edition of the standard. Ensure that is is written in full when contacting suppliers. Specifying air quality around previous editions of the standard may result in a lower quality of delivered compressed air.

How can factories use the ISO 12500 Parts 1-3 Standard to their benefit?

This standard is critical in helping factories know that they are purchasing a high-quality product. We highly recommend that factories request a written confirmation from their vendor saying that their filter conforms with the ISO 12500 Parts 1-2 Standards.

Coalescing filters are probably the most important items of purification equipment in a compressed air system as they are designed not only to remove aerosols (droplets) of oil and water, but also to remove solid particulate and micro-organisms. For this reason, ISO 12500.1 is of most importance.

ISO 12500.1 has introduced two challenge concentrations of oil aerosol to be used when testing coalescing filters, these are 40mg/m3 and 10mg/m3. The new standard requires filters to be tested using the existing test method and equipment shown in ISO 8573.2 whilst using one of the two challenge concentrations. In addition to this, ISO 12500.1 requires filters to be "wetted out" which is representative of an operational filter. Recording of the filters initial saturated pressure drop has also been included, again to give a more accurate
and representative indication of the filters operational costs. Three examples of each model requiring validation must be tested and each tested three times. Published performance data is then based on calculating an average of all the tests in order to provide the person selecting a new product with a more representative indication of performance.

Let’s discuss energy cost saving opportunities with filters.

We focus on ensuring compressed air quality at the lowest required energy costs. There are ways to do this when one examines filtration and dehydration of compressed air systems.

With filtration, the focus is on pressure loss. Remember the rule of thumb that you need one (1) horsepower to create every two (2) psi. If you need 100 psi pressure to run a machine, you might have to run the air compressor at 120 psi to overcome the restrictions to the air flow created in the filters, dryers, and piping system. When we look at filtration energy costs we look at differential pressure.

Our high efficiency filter is rated at 3 psi saturated and we suggest changing it at no less than 5 psi saturated. A lot of competitors say 10-12 psi. Most filter elements start at 5 psi. We suggest a target of maintaining a 5 psi differential. Our elements are designed to maintain less than a 5 psi delta-p for 12 months.

Our initial starting “delta-p”is the same as any other brand. They all provide a specific air quality at a reduced “delta-p” when first installed. The difference comes a month or two later when the element is saturated. Parker domnick hunter designs have up to 450% more material in the oil coalescer filter element. This means that twelve (12 ) months down the road, this element can hold 450x more dirt- this would equate to 60% energy savings.

It is important that factories don’t use initial pressure drop when comparing filters – use saturated pressure drop. We also recommend that factories ask their supplier to supply data on “saturated pressure drop after 12 months of running time under given inlet challenges.”

We nevertheless pull away from changing elements on pressure drop. People buy filters for air quality but the delta p measurement is on pressure drop. After a certain period of time, filter media can rupture and the delta p won’t reflect the loss in air quality. We recommend changing based upon time, not on delta p. We recommend changing the element every 12 months. Just relying on the gauge can be dangerous to air quality. Maintenance is busy and if they see a green gauge and there is a tear in the media-bad things can happen downstream.

When should a customer purchase a Mist Eliminator vs. a coalescing filter for oil removal?

The functions of these filters overlap but they are not the same product and do not deliver the same air quality. A Mist Eliminator provides liquid oil removal to 1 ppm while a fine coalescer can protect down to 0.001 ppm. A mist eliminator should be used as an insurance policy against the separator failing in the air compressor. It can handle large slugs of oil and protect the downsteam system against such an event. We see the need for both products in the system. A fine coalescer serves a different function. It ensures air quality for your critical process.

There are firms focusing on energy audits and energy costs and we know they tend to recommend mist eliminators as the method to eliminate oil with a lower pressure drop. Our primary goal is on high quality compressed air and to ensure this we recommend that fine oil coalescing filters be used. Air quality is not a given and mist eliminators do have design limitations.


Where are the savings to be found with dehydration?

As with most technologies, the answer lies in the correct application of the technology. Earlier we discussed when and when not to use a regenerative (desiccant) air dryer. The lower dew points offered by desiccant dryers are absolutely necessary for certain applications yet caution should be taken to not apply this specification then to the whole factory.

With refrigerated dryers, we manufacture both cycling and non-cycling designs - so we are impartial from a technical standpoint. A cycling refrigerated dryer usually has a larger power requirement when working at full load. When you run it at full load, it will cost more than a non-cycling dryer at 60-100% of load (as a rule of thumb). Yet, there are intermittent-use applications where the cycling dryer will save energy for customers. The key is in the proper application. It’s also important to understand the pressure loss in a dryer. We see significant differences in the field in this area.

Thank you for your insights.


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