If, however, the gas be first passed through a scrubber so as to wash out the ammonia this danger is avoided.
The final washing for ammonia is effected in an apparatus termed a" scrubber,"which is a cylindrical tower packed with boards 4 in, thick by II in.
I is a hydraulic box with water seal; j, a coke-scrubber; k, a filter; 1, a sawdust-scrubber; m, inlet of gas-holder; n, gasholder; o, outlet of same; p, a valve with weighted lever to regulate the admission of steam to the gas-producer; q, the weight which actuates the lever automatically by the rise or fall of the bell of the gas-holder.
The water in C leaves this tower cold enough to be used in the scrubber B.
During the period of hotblowing (heating-up) S is turned so that the air-blast communicates with the generator; d and G are open; g (the damper connected with the scrubber) and V are closed.
During the period of gasmaking G and d are closed, S now closes the air-blast and connects the generator with the scrubber; V is opened, and the gas passes from the scrubber into the gas-holder, the inlet w being under a pressure of 4 in.