Stirling Water Tube Boiler.
Q. How is a water tube boiler constructed?
A. The Stirling Water Tube Boiler as illustrated, has three upper or steam domes, the steam space of all of which is connected, while the water space of the two front domes is connected. All of these three domes are connected with a lower or mud drum, which is not bricked in, but is left free to expand and contract.
The three upper domes are supported on wrought iron beams, which are entirely free and independent from the brick work. The feed water enters the rear upper dome, and descends gradually to the lower or mud drum, being heated in its descent by the escaping gases to a sufficiently high degree to cause precipitation in the mud drum of all of the solid or scale bearing matter that the feed water contains. The water then in the front bank of tubes is chemically pure, and all danger of scale reduced to a minimum.
Q. What advantages have the water tube boilers?
A. One of the great advantages of this style of boilers is its distinct circulation, being up the front bank of tubes across from the front upper dome to the middle dome, down the middle bank of tubes to the lower or mud drum, and up again the front bank of tubes, and so on in circuit. It also has great steaming capacity, and is economical in fuel. Steam is taken from the middle dome.
This marked circulation is a desideratum in boiler practice, and the Stirling may be said to be the first that has accomplished it to so great a degree.
Q. What disadvantages have the water tube boilers?
A. Expensive first cost of setting them up in brick work.
