The J-type valve is a kind of facility used frequently to return materials into risers in CFB boilers

its working behavior is very important for ensuring normal operation of the CFB boiler.A method for analysing and evaluating the working behavior of J-type valve based on pressure difference on key parts in the CFB boiler

such as the pressure difference of material layer in the riser

the pressure difference between air quantity in returned material and the main air compartment

and the pressure difference of material layer in the furnace etc.

has been put forward

and the said method being tested on the cold-state test stand.Results of test show that the measurement of pressure difference variation on key location in the furnace is helpful to undestand the working behavier of the J-type valve

providing method and measure for solving the problems

i.e.blockage and vibration of J-type valve

occurred frequently in operation of CFB boilers.