Definition of Mobrey
Mobrey is the name used for the Automatic water level controller, it comes under the category of mountings and fittings of Steam Boiler Assembly. As the name suggests, it is used for maintaining the water level in the Boiler shell. It is mostly used in smoke tube steam boilers not in water tube boilers, as the shell diameter of the former is greater than that of latter irrespective of their running capacities and working pressures.
For smoke tube boilers, mobrey is fitted externally on the nozzles coming out of the steam boiler shell curvature. It consists of a hollow cylindrical unit in which a float hangs.
So, when the feed pump works, it supplies feed water to the boiler shell and it gets filled up. From those nozzles, the water also enters the hollow cylindrical pipe of the mobrey, as a result, the float goes up.
Now during the operation of the Steam Boiler, the water gets heated up and gets converted to steam.
Meanwhile, the water level, because of this steam generation, the water level in the Steam Boiler shell goes down and along with it, the float of the mobrey also comes down.
After certain distance being covered by the float, Mobrey sends an electrical signal to the electrical panel and then panel starts the feed pumps to overcome this shortage and the float goes up again after refilling.
This system on which on which the mobrey and feed pumps in coordination are also known as the Cascade Control System.
In a Cascade Control System, it uses the output of the primary controller to manipulate the output of the secondary controller, as the output of the secondary controller is the desired one. Here the primary controller is the mobrey and the secondary controller is the feed pump.
It ensures the desired quantity of the water to be maintained in the Steam Boiler Shell and also enhances the overall safety of the Boiler during operation by minimizing the manual intervention.
We at Thermodyne Boilers had supplied and installed successfully these Mobrey (automatic water level controllers) to all our clients.