Sensors and Simplicity  

Making a late but significant impression on the market has been PSM’s Bulksafe water ingress alarm system, which deploys a single sensor in each hold to provide a compliant pre-alarm and main alarm warning – thus saving costs on hardware and installation, it is claimed. Geoff Taylor, PSM Bulksafe MD, says that all firm orders covering 10 ships have so far been secured, but that follow-ons suggest a reference list that will soon extend to 200 sets.

The sensors used in the system are taken from PSM’s existing range of level transmitters extensively used in marine and naval duties. They do not have direct contact with the cargo, but rather rely on hydrostatic pressure to generate a continuously ‘live’ signal that can be constantly monitored and tested through a vacuum on the rear of the sensor that causes a diaphragm to move to emulate full operation. The sensors can even be checked and removed in a fully loaded cargo.

“All of this comes in addition to the auto self-check of the system, affording the crew peace of mind,” says PSM.

As with the Consilium system, there are no filter washing systems and no float switches. However, unlike the Metritape system, PSM Bulksafe’s is not limited to deck-only access and can be fed in also via keel ducts. PSM claims its new system is one of the lowest cost and simplest systems to install, and optionally includes dewatering controls. In all cases the systems can be installed during a voyage. It also offers the widest range of optional fittings and accessories to simplify installation at sea, says the company.

The ‘live zero’ signal provides an immediate indication of sensor health, a feature not available to simple switch devices, says PSM. Any water ingress that is detected while the tanker is underway will immediately cause this output signal to rise, triggering an alarm condition.

For additional refinement, RF admittance-based sensors can incorporate full digital communications using the global standard modbus protocol. A two-wire multidrop network links all alarm sensors to the central monitor, and embedded diagnostics in the sensor continually monitor its operational health. However, Mr Taylor says one of the reasons PSM has only latterly come into the market is that no owner has been prepared to pay for the more sophisticated all-digital system it first advocated. “as the least profitable of ship operators, bulker owners fit the bare minimum equipment,” he says.

However, he believes that with a $5,000-$10,000 product cost and a $10,000-$15,000 installation cost, the Bulksafe system challenges even the cheapest water ingress alarm system on cost, and that technically it is significantly superior to these.

 dedicated website

http://www.bulksafe.org