Errors to Avoid When Operating Your VLS TMF Crossflow
Last updated: 6/2021
Applies to: Winemakers and sparkling winemakers using the VLS TMF Crossflow.
Our Equipment, Parts & Service team has created this guide to highlight important ways in which you can avoid errors while operating your VLS TMF Crossflow. This article will detail both general and wine-specific considerations that will make your filtration smoother:
- Do not use hoses with a diameter greater than that required for the relative rate of flow. This is important as it prevents air bubbles from forming inside the hoses and increasing the oxygen content of the wine.
- Position the hoses connecting the filter to the feed and filtrate collection tanks so as to prevent obstructions. The length of the hoses must be proportional to the distance of the filter from the tanks. Make sure they are not too short (danger of obstructions) or too long (elevated pressure drops and top dead volume).
- Position the hoses so as to leave enough space for the operator to move around the filter and access the tanks..
- It is best to connect the product feed hose to the partial drain valve of the tank containing the product to filter. This is especially important if the product has not been transferred recently and large quantities of solid residues (such as yeasts) may lie at the bottom of the tank. This measure prevents these solids from clogging the pre-filter at the start of the filtration process.
The TMF crossﬂow ﬁlter can be used instead of fossil powder ﬁlters; they cannot be used to ﬁlter lees or must or used instead of rotary vacuum ﬁlters. Crossflows are best used to filter wine prior to bottling. Below are some good practices that will make filtration easier and extend the working life of the membrane:
- Decanting/racking and transferring the product before ﬁltering it.
- Centrifuging the product if a centrifuge is available.
- Clarifying pressed musts with clarifying agents such as gelatin and bentonite (at least one transfer after using bentonite is always required).
- Clarifying the pressed must by ﬂotation.
- Checking that there are no solid deposits on the bottom of the feed tank (yeasts, clarifying agents, bitartrate crystals) and eliminating them.
- Do not filter without the pre-ﬁlter ﬁtted.
- Do not use non-conforming detergents.
- Always observe the maximum working temperatures of the ﬁlter.
- Do not cause thermal shock to the plant (e.g., cooling the hot ﬁlter rapidly after washing).
- Do not use excessively hard water or water containing an elevated content of metal salts.
- Avoid filtering products with excessive content of bentonite, carbon or PVPP.
- Do not store the ﬁlter in areas where the temperature may fall below 0°C.
FILTRATION FLOW RATE
The ﬁltration ﬂow rate of a crossﬂow ﬁlter depends on the type of wine, the content of suspended solids and colloids and the temperature. Higher flow rates may dirty the membrane much more quickly than lower flow rates and may lower the volume of filtered product. Do not exceed recommended flow rates otherwise the membranes may become irreversibly dirty.
If your experience suggests that a certain type of wine is diﬃcult to ﬁlter with a normal fossil powder ﬁlter, the wine will also be diﬃcult for a crossﬂow ﬁlter. Certain wines, such as young wines with an elevated quantity of colloids, may not be suitable for ﬁltration without pre-treatment. Please remember that ﬁltering ﬂow rates are slower when ﬁltering chilled wines. Cold processing always helps precipitate the colloidal substances that can make ﬁltering diﬃcult.
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FILTRATION OF SPARKLING WINES
Sparkling wine can be filtered only in conjunction with a sparkling wine filtration kit. Before starting the ﬁltration cycle, the operator must make an isobaric connection between the feed tank, the ﬁltering plant, the ﬁltrate collection tank and, if necessary, the concentrate collection tank. This is the only way to ﬁlter sparkling wine without the wine losing carbon dioxide or the formation of foam inside the ﬁlter.