Differential gauges and pop-up indicators on filters provide a visual reading of the pressure on the inlet versus the outlet side of the filter element. This only works under a flow condition. Reading this pressure differential is important to monitor the condition of the filter element. As the filter becomes plugged with particulate matter and other various contaminants, the flow restriction through the element increases, resulting in reduced efficiency and increased energy consumption. These indicators must be read under a flow condition to get an accurate reading. Learn how and when to do this and what the gauges tell you. http://parker.com/gsf

1. August 1, 2017
Differential Pressure Gauges
on Filters
©copyright Parker Hannifin 2017
How Gauges Work and What They Tell You

2. Why Should I Change My Filter
Element?
• Filters are installed to provide contaminant removal to a specific air quality requirement,
therefore, the primary reason to change filter elements should always be to maintain air quality.
Filter elements should be replaced every 12 months.
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3. The Purpose of a Differential
Pressure Indicator
”My filter is fitted with a differential pressure gauge,
and the needle is in the green – why should I change
my element?”
• Many filter housings are fitted with so-called
“Differential Pressure Gauges”. Generally, these are
indicators and not precise gauges which offer no
level of calibration or accuracy. Typically, these will
show an area of green and red, indicating that if the
needle is in the green, the element does not require
changing.
• Differential pressure gauges are neither filter service
indicators nor air quality indicators: they simply
measure differential pressure and offer an indication
only of premature blockage.
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4. Harsh Conditions
• During operation, the depth filter media used in coalescing and dust removal filter elements is
constantly bombarded by high velocity dirt particles while also being under extremes of pressure,
temperature, and a pulsing air demand. Coalescing filters also have to contend with being
attached by acidic condensate, which can be anything from hot water to oil and chemical
additives from compressor lubricants.
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5. A Balance Between Risk and Cost
• Consideration must also be given to system pressure losses (and therefore operating costs) as
the cost of a replacement element is often significantly lower than the energy cost associated
with operating with higher differential pressures. Often, the user’s emphasis is on the cost of
maintenance and replacement parts ween in reality these costs are insignificant to those
associated with product spoilage should a filter element fail. What seems like a cost savings in
the short term can turn out to be a costly mistake.
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6. What Factors Reduce Filter
Performance?
• If the filtration media becomes
damaged, the required air quality can
no longer be maintained or
guaranteed.
• Even a hole the size of a pin-point
can result in the filter media
rupturing. Additionally, large pressure
differentials or “pressure spikes” can
also rupture filter elements in an
instant, allowing all the contamination
to be carried past the filter and into
the compressed air system.
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7. DPI Reading for a Ruptured Element
• If this should happen, the needle on
the gauge would always indicate in
the green area and the element
would never be serviced until the
user eventually detected
contamination downstream.
• By this time, it is too late, and once
introduced into the system,
contamination is very difficult to
remove and may often require
specialist cleaning of piping and
pneumatic equipment before the
compressed air system can be
operated again.
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8. Learn more about Parker’s
Compressed Air Filters - UP TO 500
PSIG
• Parker’s Finite filter
vessels eliminate oil,
water, and particulate
contamination from
large flows of
compressed air and
gas. Learn more
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9. Parker Gas Separation and
Filtration Division
Parker Gas Separation & Filtration Division possesses
several distinct Parker Filtration sub-brands related to
the compressed air and gas treatment, nitrogen
generation, and process cooling industries.
Our division has two state of the art manufacturing
facilities which are located in Lancaster, New York and
Haverhill, Massachusetts. From the smallest filter to
the largest compressed air dryer, these facilities have
the technology and expertise to engineer and build
what is required by the customer.
Our commitment to superior customer service and our
wide portfolio of products are at the core of our plan to
continually meet your needs.
Visit our Gas Separation and Filtration Division
Website
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©copyright Parker Hannifin 2017