The workings of water tanks

In previous posts on the Lynn Valley water tank, I asked about the connections to the lever on the top of the tank that the fireman uses to control the flow of water.

As with so many things, the answer is, “Google it”. I did and found an article from 1899 on water stations. It includes Figure 633 – a drawing of the mechanism that operates the valve – along with a description.

Click on the image below to read the article. (Note that the description is a couple of paragraphs below the drawing – look for the “Fig. 633” note in the paragraph next to Figure 634.)

The Workings of Water Tanks photo WaterTankValve_zps2dbf1a7d.jpg

And in case the link ever fails, here’s the description:

The valve connection of the discharge pipe with the tank is shown in Fig. 633. The connection may be made either through the side or bottom of the tank. The bottom valve connection is shown in the figure. The valve rod a is attached to the short arm of the lever b. The weight c, attached to the end of the short arm of the lever, holds the valve firmly in place. A rope is attached to the end d of the long arm of the lever and hangs within reach of the engineman. By pulling down on this rope, the valve is raised, and the water flows through the discharge pipe a to the tender tank. The vacuum pipe f admits air to the discharge pipe after the valve comes to its seat, so that the discharge pipe is quickly voided.

Having read this, I’ve decided that the second chain connection on the lever is, indeed, a weight. I’ve also learned of a detail not often seen on model water tanks: The vacuum pipe to help drain water from the discharge pipe after the valve closes. This would be similar to the pipe at the top of a plumbing stack – a detail not often seen on models of houses. I will add a short piece of brass wire through the roof of the tank to represent this pipe.

As an aside, this site includes some interesting information on a number of typical railroad structures.