Alaa Industrial Equipment Factory (AFI), which is headquartered in Dammam, has been serving the local market as a specialist in the field of bottom loading systems, by providing both technical and operational expertise to tank truck owners.

Today, the majority of the tank trucks are converted into bottom loading systems in Saudi Arabia. AFI has nine branches in the Kingdom and offices in Bahrain, Kuwait, Qatar providing products and services in the region.
Emco Wheaton is a specialist in the manufacture and supply of tank truck equipment for bottom loading systems.
Saudi Aramco has adopted the bottom loading system for loading petroleum products into tankers over past decade.
Bottom loading of petrol tankers was first widely introduced into North America about 25 years ago.
Bottom loading is environmentally friendly, safer, faster, cleaner and ultimately a more economic method of loading road tankers compared to top loading.
To meet Saudi Aramco's requirement for bottom loading/vapour recovery semi-trailer road tankers capable of loading and unloading at the Saudi Aramco Bulk plants, the trailers must be equipped with a pneumatic or mechanical, high flow sealed bottom loading and vapour recovery system.
AFI/Emco Wheaton supplies the complete system including scully grounding and overfill protection system. 

Bottom loading components
An API adaptor (figure 1) is an interface valve that allows loading coupler and delivery hose ends to be connected; Emco Wheaton adaptors conform to API code RP 1004 to ensure compatibility with couplers.
Special features of Emco Wheaton's API Adaptor include a hard anodised replaceable nose ring that can be indexed through four positions for extended life, while a flat bottom valve body ensures complete product drainage and minimises contamination. Also a two stage fixed aluminum handle gives a positive indication of valve position.
The specifications conform to API RP 1004 for total compatibility with API couplers, and it boasts a light weight aluminum construction for increased payloads.
Viton seals are standard for high octane fuels and additives, while  hydrodynamic design minimises the pressure drop for high flow rates while a stainless steel operating shaft, cam and poppet stem ensures durability of the product.

Emergency Valve
This valve, also known as foot valve, is located at the bottom of the tank compartment and is used for loading and unloading the compartment.
The emergency valve should have a nominal four inch bore and should be designed to minimise turbulence and spraying inside the tank during bottom loading to minimise the generation of static electricity.
All emergency valves are incorporated with a 'shear groove' which allows the main valve body to break away in the event of an impact leaving behind the sealing valve poppet in the tank compartment to prevent product escaping in an accident.
Emergency valves can be either mechanical or pneumatic, depending on the control system on the tanker.

Manhole cover
The Manhole cover (figure 2) is one of the key components of a bottom loading system that is fitted on the top of the tank truck.
The device has multiple functions in a bottom loading system which include sealing the compartment against liquid leakage and pressure relief functions.
The Emco Wheaton Manhole covers go through strict and rigorous tests, including Australian Drop tests, to ensure strengths of the manhole covers to make sure that product is contained in the tank, in the event of a roll over.
The fill cap assembly on the Manhole cover provides pressure relief, liquid venting and fire engulfment venting functions.
A pressure vacuum vent on the manhole cover provides  atmospheric breathing for compartment vapour space within the pressure and vacuum rating.
Compartment vapour vent
This vent (figure 4) is a crucial component on a bottom loading system and vapour recovery tanker as it controls the flow of vapour to and from the compartment.
The vapour vent can be mounted on the manhole cover or on the top of the tank and can be operated either mechanically or pneumatically.
The vent is opened during loading and unloading of the product.
During loading the displaced vapour is allowed to go to terminal vapour system, while during unloading the vent allows recovered vapour or atmospheric air to get back into the compartment.

Grounding and overfill protection from Scully
The complete bottom loading system also comes with a grounding and overfill protection system from Scully.
AFI is the authorised distributor for Scully system in the Kingdom.
The Scully kit for the bottom loading comes with Optic high level cut off sensing probe with holder (15 inches in length), and a socket with vinyl protective cap, ground bolt, five wire optic cable etc.
In addition to the bottom loading system, AFI also supplies various bulk terminal equipment such as bottom loading arms, specialty loading arms, spring loaded bottom loaders, top loading arms, API couplers, bulk plant and terminal storage tank equipments such as floating suctions and accessories.