Bulk liquid transport —especially when it involves hazardous chemicals— carries more risk than other types of transportation. Have an accident with a trailer full of groceries and you lose two pallets of Cheerios. In contrast, a tanker truck collision could trigger the shutdown of a multimillion-dollar production line because a crucial raw material has washed over three lanes of Interstate 80.
To help you better understand the shipping of bulk liquids, we’ve created an eBook: Liquid Bulk Freight 101. And, in this article, we’ll examine the first part of that eBook: the equipment used in liquid bulk shipping.
Bulk Liquid Transport Equipment
The typical liquid bulk trailer holds 6,000-7,000 gallons, while some carriers offer “tight fill” tanks that hold only up to 5,000 gallons. The benefit of a smaller tank is that you ensure that the liquid won’t get agitated in transit, reducing the chance of forming foam.
A bulk liquid tank is made of stainless steel or aluminum and can be insulated or non-insulated. It may consist of a single compartment or be divided into two-to-four compartments for hauling different commodities at once. There are also special food-grade trailers for products such as fruit juice, vegetable oil and food ingredients.
At the top of the tank is a dome, which is open at the time of loading. It’s extremely important, at that time, to make sure that nothing but a hose and the liquid product pass through that dome.
Most insulated trailers come with steam coils to protect cold-sensitive liquids. When the trailer is parked, these coils can be attached to a source of steam, which then circulates through the coils to maintain the temperature of the product.
Some trucks also have piping that draws antifreeze from the tractor’s radiator and circulates it around the trailer, warming the product while the truck is on the road. It’s important to note that this in-transit heating system is meant only to keep the temperature of a product from cooling off too fast. It is not designed to make a product warmer than it already is.
So, before you ask for in-transit heat, consult with your bulk liquid carrier or broker to make sure this is exactly what you need for your specific product. In some cases, the antifreeze circulating through the in-transit heat system might be significantly cooler than the product you’re shipping. In that case, the system could actually cool your product, taking it significantly below the optimal temperature.
Weight and volume
In bulk liquid transport, the key measurement is volume – not weight. So, when you ship your product, you’ll need to tell your carrier or broker how many gallons you’re shipping. That’s the only way to figure out whether you need one truck, or two, or more.
Weight does matter, however, when it comes to complying with federal regulations. Given the weight of the typical bulk liquid trailer and the tractor pulling it, don’t count on loading more than 45,000 lbs. on one truck if you want to stay within the Department of Transportation’s 80,000-lb. limit on gross vehicle weight.
Also, remember the DOT’s maximum weights on single and tandem axles. You might be used to the idea that you can move product around inside a trailer to rebalance the weight across the axles. In a tank trailer, rebalancing is extremely difficult if not impossible.. Liquid seeks its own level.
Pumps and compressors
Air compressors or pumps are used to load and unload bulk liquids. An air compressor – which blows compressed air through a hose – is typically the preferred method as it’s more convenient and makes less of a mess. The drawback to a pump is that the liquid passes through it. This means that you need to clean it after each use. It also means you can’t use a pump for corrosive liquids, which will eat through the metal and eventually ruin it.
An air compressor cannot, however, be used to transport flammable liquids. It produces static electricity, which can create a spark. A pump will then be used for those flammable commodities, as well as other liquids that simply flow more easily when pumped than when pushed by air.
Some very viscous liquids—that is, liquids that are thick and sticky—need both methods. The air compressor will blow the liquid toward the pump, which then moves the product into the hose.
Key questions that dictate equipment need
Before you start looking for equipment to move a liquid bulk shipment, know the answers to these questions your carrier or broker will ask. Or work with a knowledgeable bulk freight broker.
- What is the product?
- What are its special properties? (Hazardous? Temperature sensitive? Does it require insulation?)
- How many gallons are you moving?
- From what kind of container(s) will you load it?
- What width of hose do you need for loading, and how many 20-foot lengths?
- What fittings and adapters do you need for loading?
- Into what kind of container(s) will you unload it?
- What width of hose do you need for unloading, and how many 20-foot lengths?
- What fittings and adapters do you need for unloading?
- Do you need a tank that unloads from the center or from the rear?
- Does the receiver’s facility require any specific safety equipment?
To read more about the basics of bulk liquid transport, download our eBook. And, when you’re ready to get your own liquid bulk products on the move, contact Bulk Connection to speak with an expert that’s been transporting bulk liquids for over 30 years.