Boiler feed pumps and injectors

The plans detail three methods of feeding water to the boiler

Hand pump
This is a standard fitting on most locomotives, but due to its displaced volume, it's not a very convenient way to fill an empty boiler.

Some builders don't fit this kind of pump at all, choosing to fill a cold boiler by other means.

Axle driven pump
These are commonly fitted, but they aren't very efficient and are often dispensed with. The plans detail such a pump. If this is fitted and Don Young's modifications to the frames are followed, the hole for the pump body needs to be moved as shown in the plans. This is because the frames are cosmetically changed where the pump stay is fitted so it's no longer level with the bottom of the hornblocks.

If you don't plan to fit the pump, the stay can be moved slightly towards the rear of the locomotive so that the fixing holes don't need to be countersunk. The heads of the screws would foul the rear of the wheels as drawn if hex headed screws are used.

Alternatively, if you have a completed locomotive without a pump, here's a way to overcome that with instructions (in German) using a split eccentric boss clamped to the shaft.

The reason for this being necessary was because the two injectors stopped working when the water in the side tanks heated up. As drawn, SPEEDY doesn't have any boiler insulation and there's no insulation anywhere for the side tanks. A new boiler is currently being designed to allow for insulation while retaining the correct scale dimensions. More to follow on that when it's complete.

There's no reason why the side tanks can't be insulated and perhaps have a thin lining of polystyrene sheet of the type used behind wallpaper. The volume of water is quite small so it doesn't take much to heat it up.

The plans don't show a balance pipe between the side tanks but one it necessary. One option is to take a pipe from each tank and take it to the bottom of the axle driven feed pump. That way you get the tanks joined and a generous feed to the low pressure inlet valve of the pump.



The pump uses old fashioned graphite packing for the seal but this can be replaced by an 'O' ring if the housing is machined appropriately. Alternatively, an 'O' ring or preferably a 'Quad Ring' could be fitted on the plunger.

http://o-ring.info/en/technical%20manual/ERIKS%20-%20Technical%20Manual%20-%20Quad-rings.pdf



Injectors
Speedy has one of these but one option is to fit two of them instead, and dispense with the Axle driven pump. Injectors won't work with hot water and it may be necessary to have an additional cold water supply on the driver's car. The plans don't detail any boiler insulation and this will be addressed on another page. If the boiler is modified to allow a significant thickness if insulation, this will help keep the water tanks cool. In any case, it may be a good idea to put as much insulation as possible between the boiler and the side tanks.