If you follow this blog, you’ve probably noticed we spend a lot of time talking about Waukesha Universal Series Pumps and Graco AODD’s. In todays post, we’re going to talk a little about one of our favorite pieces of process equipment to pump through- Votator Scrape Surface Heat Exchangers (SSHX).
What is a Scrape Surface Heat Exchanger?
Let’s start with the basics- what is a Scrape Surface Heat Exchanger? We talked a little about this in a prior post, but to recap, a Scrape Surface Heat Exchanger is a tubular type heat exchanger that uses a center shaft with blades to “scrape” product off the walls. This allows for uniform heating and cooling of viscous products. This not only prevents burn on and product fouling, but also enables even and controlled heating and cooling for products of all viscosities (from soups to sandwich creams).
The “heating and cooling” piece is really just the beginning of what a Votator can do. Speaking in broad terms, yes, that is what a Votator does in its most basic form- it heats or cools whatever product is pumped through it using an externally supplied thermal transfer fluid (most commonly steam, water, ammonia, or freon).
Now, let’s get a little more granular. There are six secondary processes Votator’s help us accomplish that really make the Votator an invaluable piece of process equipment- crystallization, pasteurization, sterilization, gelatinization, freezing, and evaporation.
Crystallization is very important for fats and oils applications. When you’re creating shortening or margarine, you’re essentially cooling fats- changing state, from a liquid to a solid or solid like material. Votator’s are critical in controlling this cooling and crystallization process so we get a consistent product every time.
Pasteurization & Sterilization
Pasteurization, as we talked about in our post on UHT, is the process of killing microorganisms with heat to increase shelf stability. Sterilization is like pasteurization on steroids and turns up the heat to get even higher kill rates and incredibly long product shelf life. There are a number of different types of heat exchangers that can be used to accomplish this, including plate and frames, shell and tubes, as well as tubular heat exchangers, but for high viscosity products, Votator is the way to go.
Gelatinization is the hydration of starches. How does a Votator help with that? Well, when we heat water and we get it hot enough, the water and the starch come together to create a high viscosity gelatin. This gelatin is used in things like puddings, cheese sauces, and ketchup to add texture, viscosity, and mouthfeel to products. Votator allows us to heat these high viscosity gelatins with ease.
Freezing. Seems simple enough, right? Not so fast- no, we’re not making ice cubes. In this case, we’re using the Votator to slush freeze products. This is great for ice creams and frozen desserts. Ice cream is more than a sweet dessert- it’s a multiphase soft solid composed of ice crystals, casein micelles, air cells, and emulsion droplets. Controlling the formation of these different phases as ice cream freezes has a huge impact on overall quality. The Votator gives us that control.
While not the Votator’s wheelhouse, we can still use it and some supporting equipment to strip water out of a product. We would accomplish this by using a chamber under vacuum to pump product through the Votator. An application for this is caramel, where we bring in a product at a certain brix (sugar concentration) and use the Votator to remove water, increase the solids, and thicken the product. We need the scraping action of the Votator to prevent product fouling and burn on, as well as for even, controlled heating.
At the end of the day, a Votator is a heat exchanger that uses a shaft with blades to scrape product off the heat transfer walls. And while this may seem like a relatively simple technology, it allows us to do much more than just heating and cooling. Votators are great for a number of subcategories of heat exchange including controlled crystallization, pasteurization and sterilization, gelatinization, freezing, and even evaporation. If you have any questions about Votator or any of these applications, please contact a Triplex Sales Engineer today!