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How to efficiently evacuate low to high viscosity products
Graco offers three ranges of unloaders to evacuate products of any viscosity. We explain the key differences between them.
Graco offers three series of unloaders: manual pail unloaders; manual and automatic drum unloaders; and manual and automatic bin unloaders. Automatic means that the unloader can be programmed. This enables you to create a sequence, and it provides basic batching capabilities. An automatic unloader can also be interfaced with a scale or a flowmeter.
Graco's Pail Unloader
The Graco Pail Unloader is an entry-level manual pneumatic model that’s capable of unloading 20- and 25-liter pails. Its construction is food grade approved, making it useful for general foods, personal care products and cosmetics. It incorporates a 316 stainless steel SaniForce 6:1 piston pump. It’s designed to evacuate small volumes of high-viscosity materials.
The only configuration possibilities are in the wiper options. You can select a wiper made from Nitrile (Buna), which is a very soft material. Alternatively the wiper can be made from a combination of Nitrile and PTFE. The upper part of the wiper is made from Nitrile, while its lower part, which is in contact with the fluid, is made from PTFE. PTFE (Teflon®) is easy to clean, and is fairly resistant to some aggressive chemicals.
The Pail Unloader is available with EN2.1 or EN3.1 material certification. It’s ATEX approved so it can be used for cosmetic products that contain alcohols or flammable fluids.
Graco’s Drum Unloaders
Drum Unloaders are designed to evacuate 200- to 250-liter drums. They incorporate an inflatable seal, offering a solution for both straight and tampered drums in the food, beverage and personal care industry. Drum unloaders come in a variety of different configurations, so choosing them requires a step-wise approach:
Step 1: Select the frame. This can be carbon steel or stainless steel. Carbon steel is epoxy coated and is the entry-level solution. For industrial applications in which the drum unloader has to be completely cleaned, stainless steel is the preferred material.
Step 2: Select the wiper. You can choose between a static wiper and an inflatable wiper. The inflatable wiper provides superior evacuation as it makes a better seal, so is the best choice to evacuate costly materials such as cosmetics when you need the highest possible evacuation rate. The static wiper is made from Neoprene, while for the inflatable wiper you can choose between Neoprene or EPDM.
Step 3: Select the pump. Here you can choose between a piston pump, a shovel pump and a diaphragm pump. Which one to select depends on your application. Here are some basic guidelines:
- If the fluid is flowing, choose a diaphragm pump. Typical applications for a diaphragm pump include fruit juices, very low viscosity sauces, and some basic ingredients of cosmetics. It’s also a good solution if the fluid contains abrasives or small particles. For example, a diaphragm pump is ideal to pump tomato cubes because it will push the cubes but not crush them. The downside of a diaphragm pump is its limited pressure range.
- If you need to squeeze a fluid, then a piston pump is preferable. Typical applications include tomato concentrates, ketchup, thick banana paste, or fluids with a viscosity between approximately 80,000 and 250,000 cPs.
- If you need to scoop your product, choose a shovel pump. Typical examples are lanoline wax and high-viscosity cosmetic silicon. A 12:1 shovel pump can easily evacuate 200-liter drums containing products with viscosities ranging between 500,000 and 800,000 cPS.
Step 4: Select the control system. The control system for a drum unloader can be exposed, enclosed or electronic. An exposed control system cannot be cleaned with a pressure washer. An enclosed control system can be pressure-washed, but it's not automated. An electronic control system enables the process to be fully automated, and it can be cleaned with a pressure washer.
Step 5: Select the accessories. These are the caster kit or a drum dolly and ramp.
Step 6: Select the required certification. Again, this can be either EN2.1 or EN3.1 certification, depending on the specific application.
Graco's Bin Unloaders
Graco's Bin Unloaders can evacuate medium- to high-viscosity products from 1136-liter containers without diluting or heating the contents. Each system includes a pump ram with an inflatable seal that securely fits the container for evacuation rates up to 99%. Common applications include the transfer of tomato paste, peanut butter, jams and jellies, icing and frosting, caramels, corn syrups, toothpaste, and more. They can easily handle products with a viscosity up to 1 million cPs.
These bin unloaders are designed with numerous built-in features to protect foods from contamination. They contain piston pumps with built-in sanitary flanges, quick knockdown connections and an FDA-compliant air motor shroud, making cleaning and sanitization an easy process.
A closer look at the electronic controls
An electronic controlled unloader provides automation of the unloading sequence. This minimizes required operator interaction, allowing operators to multi-task easier, and results in more consistent operation from shift to shift. It removes operator guesswork for system start/stop points.
Another benefit is that electronic control enables batch output and allows the unloader to be connected to a flow meter or scale. Ingredient and end product recipes can be stored, along with batch volumes for different recipes. Electronic control also tracks and reports usage volumes and job volumes for increased quality control when connected to a measurement device for batch mode.
Need help selecting your pump?
Graco offers an online Sanitary Unloader Selector. This enables you to go through the selection and configuration process for your unloader easily and at your own pace. If you require further assistance, or would like to see a demonstration of an unloader, please fill in the contact form below.
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