Question

Which type of boilers use orifice to control the flow circulation?

(a) Natural circulation boilers

(b) Forced convection boilers

(c) Once-through boilers

(d) Positive forced circulation boilers

I had been asked this question in an internship interview.

The origin of the question is Boiler Classification in section Steam Generators & Accessories of Energy Engineering

Answer 1

Correct option is (b) Forced convection boilers

To elaborate: In these boilers water is circulated by using an additional pump. These boilers often use orifices to control the flow circulation. Orifices are located at the bottom of the tubes that ensure even distribution of flow through water wall tubes. These boilers can generate steam upto about 200 bar.