Troubleshoot of Deck Crane Overload Valve
One of the safety functions of the deck crane is a pressure switch or overload valve which is limiting the main pressure in the hoisting circuit.
The valve is mounted in hydraulic system to prevent the crane from overload. Stops the crane in case of overloading.
I attended on board of the vessel for inspection and troubleshoot of deck crane overload valve. I found this valve wrong adjusted. The overload valve is mounted in the hoisting circuit. The hoisting winch is handling the crane hook.
Before going up in the crane I am trying to get as much information I can from the person in charge. Also I check the Manual of the crane.
In this case they complain that pressure in the hosting circuit is to high. I checked the pressure and I found set higher than it should be. Usually the safety valves are sealed. On this pressure switch the seal was cut and It could be seen that someone was working it without seal it again.
This pressure switch is adjusted when a proper load or weight is available. Keep it mind that I need it an overload around 40 Tonnes or greater.
When the weight on the cargo hook is too heavy the pressure switch of the deck crane will stop the crane.
I started the crane and lifted. The pressure gauge installed at one port of the hoisting pump was indicating a higher pressure and was is wrong adjusted. I adjusted according to Maker procedure.
Note: These valves are sealed and should be adjusted be qualified engineer.