Electrically heated riser pipe for a fluid supply system

DETAILED DESCRIPTION Referring now to the drawing, in which the same reference numbers designate the same elements in all of the figures, there is shown a water supply system including a riser pipe 10 terminating at its lower end in a valve 11.
In the installation of the water supply system, the valve 11 is connected to an underground water supply line (not shown) which is located below the frost line.
The upper end of the riser pipe 10, is connected through a "T" 12 and a globe valve 14 to a suitable utilization device such as a mobile home or a stock waterer (not shown).
The other outlet of the T 12 has a bushing 16 in it through which passes a hollow rod 18, which extends all the way inside the riser pipe 10 to the valve 11.
The lower end of the hollow rod 18 is rigidly attached to the valve poppet 20 for the valve 11; so that rotation of the rod 18 can be used to effect the opening and closing of the valve 11 at the bottom of the unit.
A handle 21 is secured to the upper end of the rod 18 which extends through the handle 21 and is capped by a threaded cap 23.
In normal usage the cap 23 is in place and prevents water from passing through the hollow rod 18.
To evacuate water from the riser pipe 10 when the unit is not in use, the handle 21 first is rotated clockwise to thread the poppet 20 downwardly to close the valve 11.
The cap 23 is removed and the globe valve 14 also is closed.
Air under pressure then is introduced into the T 12 through a conventional air valve 26 of the type commonly used in pneumatic tires.
The valve 26 terminates a hollow pipe which opens into the T 12.
Introduction of air through the valve 26 forces the water downwardly out of the riser pipe 10, through an opening 28 at the lower end of the hollow rod 18, and out its upper end where the cap 23 has been removed.
Using this technique, all of the water can be evacuated from the riser pipe when the unit is not in use.
Under normal circumstances, however, water is supplied, often intermittently, through the riser pipe 10 to a utilization device in areas where the riser pipe 10 necessarily must pass through a zone of temperatures which are below the freezing point of water