Sanitary pumps are used in the food, agricultural, and pharmaceutical industries to transport liquids and liquid–solids. This chapter provides a guide to sanitary pump selection and use. “Sanitary” means that the pump is cleanable. Sanitation standards for pumps are reviewed. Four classes of sanitary pumps are described and a decision tree for selecting the best class for a given application is introduced. Five application requirements needed for pump selection are outlined: process requirements, product properties, operational requirements, cost, and safety. Installation details and cleaning processes for pump s are assessed.
Sanitary pumps used in high-purity applications such as pharmaceutical processing and biotechnology typically require a level of design that is higher than in most other processing industries. The pumps not only need to transfer product efficiently, but they must also meet strict design and cleanability requirements mandated by the many organizations that establish standards for ultra-clean processing!
The first big question when selecting a pump is: ‘What type of pump do I need?’ To answer that, it helps to understand a little about pump design and consider the various pump styles that are available to fit your application.
Each of these categories is distinguished by the mechanics of how they transfer fluids. Pumps in both categories have advantages and disadvantages depending on your high-purity requirements, and both have the necessary hygienic features suitable for high-purity processing. This article will outline the following sanitary pumps for commonly used high-purity applications.
What is Solvent Extraction?
Solvent extraction is the process of diffusing a solvent into oil-bearing cells resulting in a mixed solution of oil and solvent. It is one of the most popular methods of separating oils and fats from oil-bearing materials as opposed to other mechanical processes (such as expellers, hydraulic press, etc...) primarily due to the high percentage of oil recovered which can range upwards of 99%+ as opposed to the 85%+ of other methods. The common solvents of choice range from butane, hexane, and pentane among a handful of others, each of which is favored because of several factors: commercial economics, a low boiling point, and in the case of consumption grade product, a non-toxic impact. Distillation of the resulting oil mixture allows recovery of the alkane hydrocarbons (your "hex/but/propane") to be reused at minimal costs.
Solvent Collection Tanks
The extraction/collection tank collects the extracted oil and solvent at the end of the process. The larger the vessel the more trim (raw plant matter) you can process at once. It is not uncommon for a large collection vessel to be the repository of multiple material columns, provided it has enough volume to hold the volume of solvent initially. Once in the collection vessel, the solvent is warmed until it reverts to a gaseous form which can then be removed with a recovery pump such as the Haskel we carry. The extracted oil ("drop off") can then be poured into an external container for further vacuum purge if necessary.