High Pressure Pump Filters
To ensure optimum pump life, it is important that the incoming fluid is filtered properly. It is recommended to use filters from the Danfoss filter product range as the various filters on the market differ greatly.
Using the filters from the Danfoss product range is the best way to ensure proper filtration. If the filter is not purchased from Danfoss, it is important that a filter with equivalent properties is used.
Filter element efficiency for a particular micron (μ) rating is determined by the Beta value for that micron rating. The efficiency is calculated as Beta value minus one divided by the Beta Ratio then multiplied by 100.
The following table shows the Beta value, the corresponding efficiency, and the number of particles that will pass through to the downstream side of the element for each 100,000 particles seen in the upstream side of the element.
For example, an element with a Beta Ratio of 5000 for a particular micron rating has the following efficiency:
(5000-1) / 5000 is equal to 99.98% efficiency.
Filtration requirement
The Danfoss PAH, APP and CLP pumps require water with no particles larger than 10 micron (10 μ). Thus a 10 μ absolute filter with a Beta value > 5000 must be used. - 10 μ means that particles of 10 μ or larger in size will be caught by the filter. - 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 through the filter, as it only filters the fluid according to the diameter of the particles. - The Beta value > 5000 refers to the efficiency of the filter. A filter with a Beta value of > 5000 catches 99.98% of the particles being 10 μ or larger. This means if there are 100,000 particles in the fluid (10 μ or larger), only 20 of them would pass through that filter. Other types of filters on the market have a Beta value > 10 (90% efficiency), and these filters would allow 10,000 of the 100,000 particles to pass through the filter.
Filter 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
Features
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.
Applications
The Danfoss filters can be used in a wide range of demanding applications such as:
- General water filtration
- RO/DI water filtration
- Various chemicals
There are 2 factors to consider when selecting the right filter:
a) The flow through the filter
b) Amount of dirt in the fluid
If the fluid is relatively clean, 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 dirt 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.
