Filling and emptying a home-made parabolic trough solar kettle
by Stephen Hewitt | Published
The photographs here show a working solution to the problem of pouring water into and out of a home-made solar kettle that heats the water in a horizontal copper pipe.
This kettle was described in an earlier article. It heats its water in the 22mm pipe, which is closed at one end and has a right-angle bend at the other for a spout. While the water is in the kettle, the spout is in the upright position. To pour water out the pipe can be rotated so that the spout points downwards, as it does in Figure 1.
As noted in the first article, in practice it has usually proven difficult or impossible to get water in or out only by rotating the pipe to raise or lower the spout. Usually the pipe must be tilted too. The mechanism described here allows the pipe to be tilted without having to tilt the whole kettle.
This is achieved by mounting the open end of the pipe on a hinged arm which allows it to be raised for filling or lowered for pouring water out. To precisely position the pipe on the focal line of the trough during heating, a side branch off the main arm rests on an adjustable stop shown in Figure 2. This adjustable stop is the wood screw seen passing through the wooden plank. Its height can be changed by screwing it further in or out and the side branch rests on its head. This branch is mounted on the main arm on a pivot, made here by attaching it with a single wood screw, whose head is visible in Figure 2.
The open end of the pipe can always be freely raised because the branch rests on the stop only under gravity. It can be lowered by rotating the branch on its pivot so that it no longer reaches its stop as shown in Figure 3, where the arm has been left hanging down.
During construction of the kettle, the length of the arm and the position of the stop are adjusted together so that when the branch rests on the stop, the copper pipe is correctly on the focal line. The length of the arm can be adjusted by screwing its threaded rod further into or further out of the wood attached to the hinge.