Safeguarding Hydrants Against Freezing.
The following system was evolved by Mr. A. A. Cowles, of the Ansonia Brass & Copper company, and Mr. Walter G. Clark, electrical engineer, to provide a means (for their own use) of safeguarding hydrants against the liability of freezing and to enable them to test hydrants without filling them with water.
The method which they evolved, tested and have since patented has proven so efficient that it is being taken up by other corporations and municipalities.
Cnder this method they force the water from the hydrant back into the main through the main valve at the bottom of the hydrant by applying a gas or air-pressure on the surface of the water in excess of the pressure of water. This forces the water contained in the hydrant back into the main, and the pressuregauge on the connection near the hydrant shows a drop in pressure, when the hydrant is free of water, and becomes an indicator for the guidance of the operator.
After the hydrant is free of water, the main valve is closed while the air-pressure is still on. The opening of the drip-valve permits the airpressure to escape through the drip into the ground, clearing out the valve and eliminating the last trace of water from the hydrant. The hydrant, being now entirely free of water, cannot freeze, and the fact that the water contained in the hydrant has been forced back into the main has cleared the valve-seat of any mud or chips which might have prevented the proper closing of the valve. If hydrants are located in low or w’et ground, where surface-water might work up into the hydrant, through the drainvalve. then it is advisable to plug the drain valve entirely and by this method torce the water hack into the main and close the main valve tight. In setting new hydrants, it is not necessary to set hydrants with drain-valves, so a considerable saving can be made ir. the price of new equipment.
The hack current of water through the valve clears the seat and prevents damage through closing down on obstructions, which is the usual cause of leaky main valves. This system enables the operators to be certain that the hydrants are entirely free of water before they leave them and. also, that the bottom valve is tight shut, and the time required to force the water out being but a small fraction of a minute will not permit a shell of ice to form inside the barrel of the hydrant even during the coldest weather. The necessary pressure for forcing the water out could be supplied by means of hand-operated air pumps; but, in using the hand-operated equipment, it is necessary to take into consideration that the man may become tired before the water is entirely out of the hydrant, and, to avoid this possibility, there is supplied, instead of handoperating air-pumps, steel cylinders, mounted on a small cart. The steel cylinder is filled with liquified carbon dioxide gas, a reducing valve, the necessary gauges, hose and connections, so that the application of the necessary pressure to the hydrant becomes merely a question of attaching the apparatus and opening the valve, and the hydrant is free of water in from fifteen to thirty seconds.
The carbon dioxide contained in the drum is the same gas used in the drug stores for making soda water which is sold over the counter, and each drum contains enough gas to test 100 hydrants.
Where fire departments are equiped with steam fire engines, a small air-compressor is atached to the fire engine in such a manner that it is throwm in service only after the fire engine has ceased to pump water. and the com pressed air is used to force the water from the hydrant.
It is not necessary to make any change in the hydrants, drill and holes or make any attachments to the hydrant, except during the time the apparatus is in use in freeing the hydrant of w’ater, as there is supplied this special cap containing the check-valve, and, after the hydrant is free of water and the gas blown out through the drip-valve, the cap is removed and the ordinary hydrant-cap replaced.
If hand-pumping outfits are preferred, there are supplied complete duplex hand-pumping equipments, with hose, valves, connections, etc., in place of the carbon dioxide sets, or the carbon dioxide sets are attached to the hose wagons.