SELFCLEAN 6.60/ 6.61
The Task
When it comes to process fluid filtration, the consistency of both the cleanliness and the operating pressures is essential to the success of any plant`s production capabilities. To meet the challenge of ensuring these requirements are met, automatic filtration is capable of achieving the following points is necessary:
- capacity to handle high flow rates while maintaining a compact, ergonomic design
- guarantee of a defined degree of liquid cleanliness
- minimization of back-flush discharge volume to reduce waste
- prevention of system pressure drops during the back-flushing process
- high level of filter surface regeneration by efficient, dynamic self-cleaning
- reduction in maintenance and operating costs through simplistic, reliable designs
The Concept
The Boll advantage lies within the ability to utilize a simple design to handle a multitude of different flow rate, material and clarity requirements, while consuming minimal operation and maintenance costs through the elimination of disposable media.
Boll 6.60/6.6 1 automatic self cleaning filters are constructed of rigid cast iron housings including the individual chambers which encapsulate the actual filtration area. Each of the five different filter sizes available has a pre-determined number of chambers, as well as a predetermined number of filter elements within each chamber. Together, this allows for the accommodation of a large variance in flow rate requirements through the filter.
The automatic self cleaning of the filter elements is accomplished through a reverse flow of a small amount of clean process fluid from within the filter, aided by compressed air as an independent energy source. Cleaning occurs in one chamber at a time while it is placed ``off-line``, that is, removed from the system flow. The result is a highly effective back-flushing process without any disruption to the system pressure, during which the filtration process continues the entire time.
The Solution
During the filtration phase, contaminated fluid enters the inlet flange and is equally diverted into all but one of the filter housing chambers (one chamber always held off-line). Within each chamber is a cluster of filter candles, each constructed of stainless steel wire mesh drawn over a spiral metal frame which is capped at the top and open ended at the bottom. The liquid is forced inside the elements leaving particles in suspension trapped on the outside of the mesh. The clean fluid then flows out the bottom of the candles and is directed through the outlet flange of the filter.
A back-flushing cycle is initiated by either a pre-set timer interval or by reaching a pre-set value of differential pressure build-up across the inlet and outlet of the filter, as detected by the Boll supplied indicator. The differential pressure increases proportionally with the amount of accumulating debris on the candles and thus can be visibly monitored at any time by viewing the dial display.
An electric motor (model 6.61) or pneumatic actuator (model 6.60) rotates the changeover plug located in the center of the filter housing, to the next sequenced to the next sequenced chamber to be flushed, thus putting the chamber formerly in reserve, which is now clean, on-line again. Rotation stops by means of a proximity switch and cam plate, with a designated position for each chamber orientation. The new dirty chamber is now off-line and is ready to be automatically cleaned.
A solenoid valve is electrically switched and pneumatically opens a normally closed poppet valve at the sludge discharge drain and at the air reservoir on the filter. Compressed air is explosively released from the air storage reservoir up into the chamber along with a small amount of clean fluid from within the filter, which together flush through the inside of the candles in the opposite direction of the filtration flow, blowing off the collected contaminants from the exterior of the mesh. The flushing solution and debris are then channeled through the center of the filter via the changeover plug, and dispersed out the sludge drain. Compressed air continues to blow through the isolated chamber for a few seconds to ensure all particles are removed. Finally, the sludge discharge and air inlet valves are closed and the chamber gradually refills with a controlled amount of filtered, clean fluid through a pilot bore in the changeover plug. Residual air is vented out the top and the chamber is now completely clean and is ready to be brought back online upon the signal to clean the next dirty chamber.
The Applications
Within the manufacturing arena, Boll automatic back flushing filters provide a low maintenance, highly efficient means of removing contaminant solids in emulsions, cutting oils and alkaline cleaners.
The models 6.60/6.6 1 filters can be seen in a multitude of manufacturing environments around the globe with emphasis on central coolant/oil systems, individual machine-tool high pressure skids, aqueous parts washing equipment, and heat treat quenchant applications.
Boll automatic filters are designed to serve as the secondary means of filtration in any given system, whereby finer particles that bypass the primary filter are removed to obtain the final clarity requirement. Additionally, they are commonly integrated into systems as protection barriers for downstream pumps, cutting tools, nozzles, etc, where they are not necessarily filtering to a finer clarity, but rather functioning as the ultimate road block against excessively sized ``fliers`` that may bypass the main filtration system and shut down equipment.
Through the use of precision mesh permanent media elements, Bollfilters are able to establish a maximum allowable particle size of any contaminant, in any process fluid.
The Advantage
- fully automatic operation
- long maintenance intervals
- simple maintenance procedures
- low operating costs
- exact filtration fineness provided by precision stainless steel wire mesh elements
- off-line automatic cleaning by compressed air results in no system pressure drops during the simultaneous filtration process
- large filtration surface area optimizes back- flushing efficiency and accommodates high flow rates
- efficient operation at line pressures as low as 22 psi
- rigid cast iron construction
- compact, modular design
