Twin rotor devices with internal clearances reduced by a coating after assembly, a coating system, and methods

A method of treating a twin rotor device the method comprising:

• providing the twin rotor device, the twin rotor device including a pair of rotors and a housing with an air inlet port and a compressed air outlet port, the rotors and the housing defining a set of working surfaces adapted to interface with each other;
• providing a first coating material dispenser-collector and a second coating material dispenser-collector, each of the first and second coating material dispenser-collectors being configured to selectively dispense and collect a coating material;
• fluidly connecting the first coating material dispenser-collector to cover the the air inlet port of the housing and connecting the second coating material dispenser-collector to cover the compressed air outlet port of the housing;
• and
• entraining the coating material in a carrier fluid with one of the first and second coating material dispenser-collectors by inducing a coating material to flow from either the air inlet port toward the compressed air outlet port of the housing or from the compressed air outlet port to the air inlet port of the housing, and thereby depositing at least some of the coating material as a coating on at least some of the working surfaces;
• and
• collecting undeposited coating material with the other of the first and second material dispenser-collectors.