Doing work requires energy. To turn a bolt, for instance, you need to provide energy in the form of torque. Such mechanical torque is usually expressed in kilogram-force meter, and both elements — kilogram and meters — are needed to do the work. Energy is also required to move material through a pneumatic conveying system, but in this case the energy is supplied by pressure differential (in newton per square meter) and airflow (in cubic meter per minute).
In a pneumatic conveying system, the air pressure in the conveying line is changed by the system’s air source, which generates pressure or vacuum.
Where the air source is located within the system determines whether it generates one or the other: When located at the system’s start, the air source pushes air through the system and the system operates under pressure.
An example of a pressure conveying system is the Ruyter Offshore pressure tank system. The pressure tank system on board of a drilling rig or offshore support vessel. The pressure tank or P-tank system is a conventional system within the offshore industry. The system deploys several pressure tanks to receive, store and discharge cement and drilling powders. The pressure tank system is named after its most important component, the pressure tanks. The tanks are installed on a jack-up, platform, semi-submersible, drill ship, platform supply vessels or any other offshore related vessel.
The bulk material is loaded pneumatically from shore onto for example an offshore support vessel. Flexible hoses connect the vessel to the onshore loading system or from the offshore support vessel to the (drilling) rig. The flexible hoses can be connected using several quick-connect deck connections. The ship provides the compressed air required for pneumatic conveying.
After being filled, pressure tanks serve as storage units until the material is required for the drilling operations. The bulk material is then pneumatically conveyed to the surge tanks by means of a pipe system. Compressed air is supplied by a compressor and air dryer installation on board the rig. If required, the material can also be discharged back to an offshore ship.
When located at the system’s end, the air source pulls air through the system and the system runs under vacuum.
An example of a vacuum conveying system is the Carlsen Continuous Suction Pump or CSP. The Continuous Suction Pump is a ship unloading system, which requires no extra equipment to handle the entire conveying process from ship to bulk carrier/truck. This enables it to work in practically any type of dock environment.
The vacuum blower pulls the air-dry material mixture to the CSP tank. Filters separate the dry material from the air going to the vacuum blower. At the bottom of the CSP tank, an airlock conveyor feeds the dry material directly into airslides, loading bellows, bucket elevators or loading bellows. This ensures a continuous conveying process from the ship to the silo, directly into truck or towards any other location.
By controlling the pressure or vacuum and airflow inside the system, the system can successfully transfer materials.