Tank trucks are extensively used by companies based in the Oil & Gas and Petrochemical sectors for the bulk transfer of fluid and gas.

Based on the type of product they are required to carry, tank trucks are available as

• Pressurized or non-pressurized,
• Insulated or non-insulated, and
• Designed for either single or multiple loads.

Apart from the aforementioned features, tank trucks are primarily classified into two,

• Top loading and bottom loading.

In this article, we’ll cover in detail about tank trucks and related equipment.

Top Loading vs. Bottom Loading

Top loading is a method of filling tank trucks by pumping chemical, petrochemical, or petroleum products using manhole covers fitted on top of the vehicle.

Bottom loading is precisely opposite to top-loading, wherein, the cargo tank is filled through valves and fittings mounted beneath the truck.

Why no more top loading is required?

*Since the market is moving towards modernization & safer work environment, Bottom loading is considered as the fastest and the safest method of loading.

Benefits of Tank Trucks Bottom Loading

In this section, we will cover in details the benefits of bottom loading as well as why people prefer bottom loading to top loading.

The choice of loading method is primarily dependent on the relative position of the storage tanks and also on the nature of the cargo. Top loading, although not recommended, is still a viable choice to load non-hazardous loads that do not require any special protection from oxygen.

However, when it comes to volatile materials, bottom loading is the only option and listed below are some of the key benefits offered by this method:

Worker Safety

A top-loading tank truck requires employees to climb to the top of the tanker and handle loading arms and other heavy equipment in order to complete the loading process. It increases the operator’s chance of slipping or falling from an elevated height. Top loading also exposes the operator to adverse weather conditions, poor breathing and other dangerous conditions.

In such scenarios, it may be difficult to react instantly in case of an emergency, which is why bottom loading trucks are ideal and, undoubtedly, the safer option. With bottom loading, the operator stands on the ground throughout the process, and can make quicker decisions in case of an emergency.

Fire Safety

If petrochemical products are top-loaded, the splashing could lead to a massive build-up of static electricity in the compartment. Moreover, a fuel oxygen mixture and the presence of moving people and equipment at the top of the tanker can greatly increase the chances of a fire or explosion. With bottom loading, you virtually eliminate such risks.

Lowers Vapor

Loading chemical and petrochemical products from the top of the tanker increases product movement and sloshing which creates move vapor and can play a significant role in causing air pollution. Bottom loading reduces vaporization of product. Moreover, bottom loading systems also usually includes vapor return facilities at a fraction of the cost when compared with top loading.

Cost Effective in The Long Run

Bottom loading islands are comparatively cheaper to design and maintain, which further eliminates the overhead costs associated with top loading. Moreover, bottom loading allows multiple tank compartments to be loaded simultaneously, which saves time and money.

Prevents Spilling

Every time a petroleum product spills on the ground, there is a potential risk of fire and pollution. The dry disconnect feature on a bottom loading truck / tank eliminates the possibility of spillage, thereby preventing any catastrophic events from taking place.

Prevents Contamination

In a top loading trucks, the manholes are kept open, which means they can easily be contaminated either by rain, dust, or any other particle in the air. Bottom loading removes any such problems.

For these reason, today more fleet owners are replacing top loading trucks with bottom loaders.

Components of A Truck Tank

API Adapters, Couplers, and Accessories

These are used to connect the tanker with the loading arm. The adapters are also used as the unloading valve at service stations.

Pneumatic Emergency Valves

Pneumatic valves are responsible for controlling the rate of pressure and the amount of air that moves through a given pneumatic system. It comes with a manual opening device that facilitates the emergency discharge of cargo.

Mechanical Emergency Valves

Designed to minimize the risk of harm to drivers and operators while also protecting the product and profit margins. Recommended for use when it comes to dealing with hazardous chemicals, petroleum, and oil.

Vapor Transfer Valves

They are designed to minimize the impact caused by pressure drop and to increase the recovery efficiency of petroleum vapors during the loading and unloading of cargo tanks.

Manhole Covers & Accessories

Manhole covers offer added security in the event of a tanker rollover and thereby prevent environmental damage and financial loss.

Dip Tubes

Dip tubes permit the transfer of liquid from a rolled over tanker to either another tanker or a temporary storage tank. They usually installed in the base of the tanker and is kept in a perpendicular plane when the tank is in motion.

Manifolds Assemblies

They are components that facilities the quick and easy pumping or metering of any product from any compartment in the most efficient manner possible.

Pneumatic Controls

Pneumatic control systems use compressed air as a method of control and is commonly used in bottom loaded tankers having pneumatic manifold or meter systems.