Lenticular Filtration Operating Instructions for Botanicals
Last updated: 7/2021
Applies to: Botanicals producers using lenticular filtration. Contains a pdf download for the complete users' guide & operating instructions.
The Lenticular Operating Instructions are available in multiple formats for convenience. Please download the full pdf here or read in your browser below:Download
- Introduction/Specifications (includes module installation)
- Filter Module Regeneration
- Storage and Maintenance
The Scott Labs lenticular filter housing is designed to be mounted upright; please make sure there is adequate overhead clearance for dome removal. A hoist or forklift is recommended for safe handling of the dome with 3 or 4 high housings. Any manual lifting of the dome should be done only with proper lifting techniques and by personnel approved for maximum lifting rates exceeding the dome weight.
- Maximum operating temperature: 284˚F (140˚C)
- Maximum operating pressure: 159 psi (10 bar) (Liquid pressure only)
- Minimum operating temperature: There are no minimum temperature limits for the hardware but consider using Viton instead of Silicone base gaskets if you intend to filter at subzero temperatures for long periods of time to avoid the risk of leaks.
- All parts in contact with product are in 316L stainless steel
- Standard gasket material is silicone
FILTER MODULE INSTALLATION
- Select a center post and securely thread on the filter housing base. Place the stainless steel deflection plate on the center post (modules will sit on top of this plate). If using Pall backflush plates, place one end plate on top of deflection plate prior to placing down a filter module.
- Load filter modules over the center post and install intermediate backflush plates (if using) between each module. After top module has been placed over the center post, place the final backflush end plate on top (if using). Screw down locking nut assembly (cap, spring and closure spindle) on top of the center post to tighten, until the tightening nut is all the way compressed. Then turn back a half to full turns. If you’re filtering very cold liquids, only turn back half a turn so that shrinking of the pack at low temperatures, doesn’t allow bypass. Flat gaskets and the whole filter pack will now be sealed once compression is complete.
- Place the filter dome over the stack of modules and secure the dome with the right ring bolts. Tighten to a complete seal. Now the unit is ready for filtration.
- If you wish to use less than a half full set of filter modules, a shorter center post can be used. Please contact us for ordering of 1, 2 or 3 module center posts.
NOTE: Backflush support plates are only compatible and recommended for use with Supradisc II single grade media. Some modules (for example Supradisc I or AKS4 carbon embedded media) are not backflushable and should not be set up or used with backflush support plates. While you may not wish to regenerate this media as is traditionally done in other industries, the backflush support plates lend extra strength and support during extreme thermal conditions, ensuring extended service life.
- Traditionally, lenticular modules are sanitized with hot water but in the botanical extracts application, you can circulate ethanol at room temperature through the media to help the cellulose fibers expand then push out the ethanol with gas and start to filter.
- Open inlet and vent valve; close drains and outlet valve.
- Commence flow with ethanol until the housing is full and ethanol comes out of the vent valve.
- Slowly and carefully open outlet valve and close vent valve simultaneously. Circulate the ethanol in a loop at 5-7 dpsi for approximately 10 minutes. Air should completely exit the vent valve. If the pump is running too slow or the source pressure vessel is under low pressure and the housing is not full, bring the backpressure up to 3 psi by slowly closing the outlet valve. This will force the liquid up to reach the vent valve. Vent periodically to release air and make sure the housing is always full of liquid, and that filter media is completely submerged.
- Open drain valves for a few seconds during the circulation to make sure no air is trapped in the valves.
- Purge ethanol by attaching gas (nitrogen) to the inlet side of the housing and blowing out the excess ethanol with a low pressure of under 5 psi. When no ethanol comes out after a while, keep the gas going and slowly close the outlet valve to bring the pressure on the outlet pressure gauge up to less than 5psi, after a few seconds at this pressure, open the outlet valve to release trapped ethanol. Repeat 2-3 times until no more ethanol comes out.
- Drain the last little bit through the drain valves.
Warning: Absolute caution should be taken if gas pressure is used. Gas pressure above the pressure vessel's rating shouldn't be used. Regulators should always be used on gas supply if using gas. Follow all precautions for working with high proof solvents. If using a pump to circulate, make sure it is rated as explosion proof and compatible with the solvent.
Filter Module Regeneration
Your media has been sanitized and you have ran an initial filtration. Now you are ready for regeneration: the action of backflush and/or forward flush to get more life and throughput from your modules. A couple quick notes before we get started:
- Non-backflushable modules can only be forward flushed.
- Backflushable media was designed to get rid of surface caking of material. In botanical extract preparation, you can simply place a trap filter, such as a bag filter housing, before the lenticular housing to catch excess plant material. Alternatively, you can drain your housing with non-backflushable media, remove the dome, and blow off residual plant material with compressed air.
- In our experience, the most efficient way to regenerate a lenticular module is done before a dpsi of 15-17 psi. If you wait until 20 psi, your filter is clogged and subsequent regeneration wouldn't be as effective.
Note: In botanical filtration applications, backflushing is rarely done because most facilities prefer to place a trap filter like a bag filter housing before the lenticular housing to catch excess plant material. Backflushable media has a stronger construction providing a longer lifespan and efficiency. In our experience, the most efficient way to regenerate any lenticular module is running ethanol in a forward flow direction to dissolve soluble compounds before you reach a differential pressure of 15-17 psi. Traditionally water is used as the liquid with which to regenerate filter media in wineries and breweries. For regeneration of modules used to filter botanical extracts, we recommend using the same strength ethanol you’re using for extraction.
Below we've outlined how to conduct both backflush and forward flow regeneration procedures.
FILTER MODULE BACKFLUSH PROCEDURE (BACKWARDS FLOW)
- If using them, backflush support plates need to be installed on the very bottom and top of the module stack (these are the slim end plates), as well as in-between each filter module (these will be the thicker intermediate plates).
- The slim end plate on the bottom should lie with the flat side on the bottom and the beveled edge pointing upwards. The top end plate should have the beveled edge facing the module. The top end plate sits loosely on the top module and is not meant to hold the top module down. It is designed to work with the turbulence of a filtration to keep the top of the module from being damaged. The intermediate (thicker) plate looks the same on both sides.
- If backflush is desired, this procedure should precede the forward flow procedure (see below).
The backflush procedure is a mechanical means used to regenerate the clean filter modules in order to improve operational economics and minimize production downtime. This type of cleaning cycle is most effective for the removal of hard, non-deformable contaminants that cake well on the filter surface. Our recommendation is to set the "plugged" (initiate cleaning) differential pressure at half the recommended final change of differential pressure. These cleaning cycles have significant practical and economic value. Experience has shown as much as a fivefold increase in filter module life.
- To initiate a regeneration, drain or push residual product out of filtration vessel. Backflush the module for 5-10 minutes with ambient ethanol. Don't expect discharged ethanol to become clear. ethanol can be reconstituted/recycled at a later stage and concentrated when the solution is saturated with materials.
- Do not exceed 7 psi (0.5 bar) during a backflush, but do try to get to 5 psi - even if just for a few seconds - for efficiency.
- Now proceed with the forward flow regeneration (see below).
FILTER MODULE FORWARD FLUSH PROCEDURE (FORWARD FLOW)
A forward flow can provide the most effective means of reducing fouling in the depth of the filter media. Regeneration is best performed at 15-17 dpsi. If your differential pressure went over 20dpsi before a regeneration, it wouldn’t be as effective. A forward flush regeneration is recommended for all media.
- Clear housing of product by pushing out with gas or draining residual product.
- Commence forward flow of ambient ethanol.
- This can be done in a loop. The goal is to dissolve soluble compounds within the depth of the media.
- Flow rate should be set to equal flow rate of the product and back pressure can be brought up to 3 psi by partially closing the outlet valve and making sure the housing is always full and the media completely submerged.
- Record pressure (dpsi).
- After 5-10 minutes of low, hold in a soak phase for 10 minutes.
- Recommence forward flow for another 5-10 minutes, then push out residual ethanol with gas or product.
- After regeneration, recommence filtration or store modules for future filtration.
Note: All pressure should always be released through drains or vents prior to removing the vessel lid.
Storage and Maintenance
HOW TO STORE FILTER MODULES
- Filter modules can be stored in the regeneration ethanol solution overnight (>30% strength).
- It is advisable to remove O-rings and gaskets, even for short term storage as ethanol can cause the O-rings to stretch or crack, resulting in unnecessary bypass.
- Filter modules can also be drained and held in the drained housing with all valves closed so that the modules don't dry out.
- Remove gaskets and O-rings from modules and store submerged in ethanol (>30% strength).
- Modules can be stored inside the housing or in suitable storage containers with lids as longas the media is always completely submerged.
- Do not allow modules to dry out between uses.
Parts on the lenticular housing that might need to be replaced periodically include:
- Locking nut assembly
- The plastic thread can become stripped over time which can lead to bypass. This will affect your filtrate quality.
- There is an O-ring in the stainless steel cap which makes the seal between the plastic nut and the assembly. It can become cracked over time and needs to be replaced before that happens.
- The base O-ring
- It is a good idea to carry spare base O-rings. They can become damaged if they slip out of position before the dome is tightened down. This can lead to the dome cutting through the O-ring.
- The eye bolts on the housing for tightening the dome to the base
- Keep the thread on these bolts lubricated with food grade grease to avoid pitting and from prematurely stripping the thread when tightening or loosening.
The Lenticular Operating Instructions are available in multiple formats for convenience. Please download the full pdf here or read in your browser above:Download