Danfoss Filter solutions Data sheet
Data sheet
Filter solutions for
Danfoss high-pressure pumps and energy recovery devices
hpp.danfoss.com
Data sheet | Filter solutions for Danfoss high-pressure pumps
1. Introduction 1.1 Cartridge filters
Cartridge filters are widely used in industrial and domestic applications for removal of suspended solids in water. The variety of cartridges available and the confusing methods of ratings, however, make selection of cartridges difficult for consumers. It becomes important for users,
therefore, to understand cartridge filters, how they work, and how manufacturers rate them.
1.2Filtration
Filtration is a process of removing unwanted solids from fluids by passing the fluid through a form of sieving material that retains the solids, but allows the fluid to pass through. Filtration efficiency is, therefore, the percentage of solid retention by the sieve. It is this “sieve” that we refer to as the filter medium, or simply the filter. A contaminant is generally referred to as the material that is to be removed from the fluid, and the clean fluid is called the
filtrate. In today’s market, manufacturers use three types of ratings to evaluate filters: nominal rating, absolute rating and beta ratio.
1.3Nominal filter rating
A nominal filter rating is an arbitrary value determined by the filter manufacturer, based upon removal of some percentage of all particles of a given size or larger.
-The rating is typical based on a weight percent (etc. 60 -95%)
-The 5-40% that pass through are NOT defined by the manufacturer (normally much larger particles pass through).
-The rating is based on a weight analysis test.
-It is NOT possible to reproduce the filter.
-Particle unloading is rising when the ∆P across the filter increases
-There is a high risk of channelling when a filter medium has some oversized pores or a wide pore-sized distribution.
-There is a high risk of bypass when cartridge-to-housing seal is ineffective.
1.4Absolute filter rating
The absolute rating or cut-off point of a filter refers to the diameter of the largest hard spherical particle, normally expressed in micrometres (µm), which will pass through the filter under specified test conditions.
-The filter is tested under a specific international well known test method (modified OSU-F2 single-pass filter test system).
-The rating is based on a particle measuring test.
-The filter is reproducible.
-Higher ∆P does not result in particle unloading.
-The filter can withstand flow pulsations as well as viscosity and temperature changes.
-There is no risk of channelling due to the high quality of the filter media.
-Absolute filtration means that the fluid is filtered both horizontally and vertically. In comparison, an inferior nominal type of filter will allow particles which are more than 10 µ in length to pass the filter, as it only filters the fluid according to the diameter of the particles.
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Data sheet | Filter solutions for Danfoss high-pressure pumps
2. Requirements |
2.1 |
Filtration requirement |
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To achive warrenty and assure the service inter- |
- The Beta value > 5000 refers to the efficiency |
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vals stated from Danfoss, the PAH, PAHT, APP |
of the filter. A filter with a Beta value of > 5000 |
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pumps require water with no particles larger than |
catches 99.98% of the particles being 10 µ or |
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10 micron (10 µ). Thus a 10 µ absolute filter with a |
larger. This means if there are 100,000 particles |
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Beta value > 5000 must be used. |
in the fluid (10 µ or larger), only 20 of them |
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would pass through that filter. Other types of |
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- 10 µ means that particles of 10 µ or larger in |
filters on the market have a Beta value > 10 |
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size will be caught by the filter. |
(90% efficiency), and these filters would allow |
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10,000 of the 100,000 particles to pass through |
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the filter. |
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β-value of filter |
Filter efficiency |
Number of particles downstream for each |
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100,000 particles upstream |
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2 |
50.00% |
50,000 |
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4 |
75.00% |
25,000 |
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10 |
90.00% |
10,000 |
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20 |
95.00% |
5,000 |
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40 |
97.50% |
2,500 |
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100 |
99.00% |
1,000 |
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200 |
99.50% |
500 |
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500 |
99.80% |
200 |
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1,000 |
99.90% |
100 |
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2,000 |
99.95% |
50 |
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5,000 |
99.98% |
20 |
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10,000 |
99.99% |
10 |
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2.2Filter types
Pleated polypropylene filter elements use the very latest gradient density micro-fibre media technology to provide a combination of excellent absolute micron ratings, high flow rates, and high dirt-holding capacity.
2.3Features
-The absolute particle retention provides excellent protection of the pump and the rest of the system.
-Compatibility with a broad range of process chemicals allows use in most applications.
-High flow rate and long service life ensure minimum downtime of the system.
-High dirt-holding capacity.
-Filter element is easily exchanged.
2.4Applications
The Danfoss filters can be used in a wide range of demanding applications such as:
-General water filtration
-RO/DI water filtration
-We recommend CIP cycles in the range of 3-10 PH
AI317041322125en-000201 | 03.2021 |
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Data sheet | Filter solutions for Danfoss high-pressure pumps
2.5Right filter choice
There are 2 factors to consider in order to choose the right filter:
a)The flow through the filter
b)Amount of dirt in the fluid (E.g. SDI).
If the fluid is relatively clean (low SDI), the filter choice can be based on the pump size as this will indicate the flow through the filter.
If the fluid is relatively dirty with small particles, a larger filter size should be chosen to increase the dirt-holding capacity. For instance, for a flow of 60 l/min fluid containing many small particles a filter for a flow up to 170 l/min should be chosen.
If the fluid is relatively dirty with larger particles, a cheaper and less efficient pre-filter should be placed in front of the main filter. This will ensure a long life of the more expensive main filter, as most of the larger dirt particles will be caught in the cheaper pre-filter.
The prefilter may be of the type ”Nominal filter”.
<![endif]>Pressure drop Bar
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Typically filter life |
2,5 |
Cartridge Pressure Drop |
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2 |
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1,5 |
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1 |
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0,5 |
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0
0 |
10 |
20 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
110 |
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Time [%] |
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AI317041322125en-000201 | 03.2021 |
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