The New Street Conduit at Toronto, Ont.
The new street conduit for the Toronto water-works is practically completed, there still only remaining a small portion of the trench, which was dredged for the reception of the pipe, to be refilled with sand, to cover the pipe and act as anchorage, when at any time the conduit may be emptied without danger of displacement or breakage of the joints.
This conduit is for the purpose of increasing and improving the supply of water which was formerly brought from Lake Ontario across the harbor through a 48-inch wooden and a 36-inch cast iron pipe. Through the former of these there was a suspicion of harbor water leaking, and the latter was of insufficient capacity.
The pipes for the new conduit arc of two sizes—that is, of 60-inches and 48-inches Interior diameter. The 60-inch takes the place of the old 48-inch wooden pipe, and supplies the new 48-inch steel and the original 36-inch cast iron; both the new pipe lines together extending over a distance of 10,680 feet. The new 48-inch pipe runs almost parallel to the original 36inch cast iron pipe, and is used in conjunction with it, and reaches from the pumping house well on the Esplanade across the harbor to a ” connecting crib ” at Haitian’s Point on Hiawatha island, a distance of 4660 feet, and at a depth varying from fourteen to twenty-four feet.
In the above mentioned ” connecting crib ” there is a water tight chamber 8j4 feet square by 16 feet deep, which is fed by the 60-inch steel pipe, and discharges through the 48-inch steel and 36-inch cast iron pipes. The 60-inch steel pipe runs parallel to the old 48-inch wooden one, now abandoned, for a distance of 6oao feet across Blockhouse Bay, and through a cutting in the island to a crib on the lake shore, where it joins a 72-inch wooden pipe, formerly laid and still in use, which projects into the lake 2357 feet and terminates at a depth of 30 Icet in an open crib known as the “ intake crib.”
The intention of the department is to increase the length of this 72-inch lake pipe for n distance of 380 feet, thereby getting water at a depth of 60 feet, where there are cold springs, and also where there will be no trouble caused by the disturbances of storms. The materials for this extension are now on hand, and the work will be proceeded with next spring when the weather becomes favorable.
The pipes for the conduit were made of ⅜-inch Scotch steel, single riveted and well caulked, in lengths of 57 feet. The flexible joints have a body of the same material as the pipes, with a cast iron turned ball riveted on, and a U-shaped rim inside the socket, filled with soft pig lead, projecting «¾inch beyond the U iron rim and working upon the smooth surface of the ball.
John Abell, of the John Abell Agricultural Works, Toronto, Ont., was the contractor for supplying the 60-inch pipe; Win. If. Low, of the Central Bridge Works, Peterboro, Ont., supplied the 48-inch and 60-inch flexible joints and 48-inch pipe, and F. B. McNamee of Montreal, P. Q., with F. Simpson, C. E., as his engineer, was the contractor for the laying of the pipe, etc., etc.
In the total length, 4660 feet, of the 48-inch part of the conduit there were 65 flexible joints used on account of the irregularity of the bottom of the harbor, a large portion of which was of rock, and in some places this rock had to be blasted and dredged to a depth of eight feet, or twenty feet below water level, in order to keep a gradual grade and give a depth of fourteen feet of water above the pipe to satisfy the requirements of the harbor commissioner for navigation. In the 6020 feet of the 6o-inch portion there were only fifteen flexible joints used, as the trench dredged was either in sand or soft clay and could therefore be kept at a comparatively even grade. The joints were merely used to give a flexibility to the pipe in case of future settlement, and to hasten and lessen the labor of laying, for they did away with the necessity of keeping the exact line and grade from start to finish, that would have existed with all rigid joints, and which was actually found impossible on account of the soft, yielding nature of the soil.
The 48-inch flexible joints were riveted directly on to the pipes, first being taken apart in the centre by unbolting the flanges that encircle the ball, and thereby separating the ball end from the socket end; the ball end was riveted to one pipe and the socket to the next in order of laying. After the riveting was completed the pipe with the ball end was taken and placed in position at the bottom of the trench, having the forward end held up from two to three feet in a sling from a scow in order to expedite the slipping on of the socket of the next pipe over the ball, and to allow the divers to get underneath to rebolt the centre flanges. This bolting being completed and everything fast, the joint was lowered and the end of the second pipe held up, and so on to the completion of the 48-inch pipe.
This slight moving or bending of the joint after it was tightened lessened the liability of straining, compressing or wearing away the lead upon the ball, which is no doubt the case with large pipes of the ordinary run ball and socket joint. Where it was found unnecessary to use flexible joints with this sized pipe, sleeves of the same material as the pipe were substituted, joining two pipes on land or making a total length of one pipe about 120 feet.
The connections of the 60-inch pipes and their joints were made by means of cast-iron flanges having a faced projection of one-quarter of an inch, and outside the projection a threequarter-inch pine packing between the two facing flanges. The two faced projections, together making a half inch, it consequently follows that the packing was crushed to two-thirds of its thickness in order to allow the faces to touch. The gasket was tied to the one flange with thin wire before the pipe was lowered into the water, and was afterwards held by the projection on the inside and the bolt on the outside. The majority of the connections were made under water by divers, the exception being when a flexible joint was first fastened to a pipe before lowering it.
This 60-inch pipe was laid commencing with a flexible joint, the forward end being held up at a grade of from one to three feet, with blocking made of 2-inch hemlock boxes filled with sand, according to the nature of the bottom of the trench. The next pipes, ranging from five to fifteen per flexible joint, were brought out and fastened with rigid joints, and blocked up in succession until the extra weight of each pipe by degrees brought the whole to a level grade by sinking the blocking into the ground. Then another flexible joint was used, thereby taking the leverage off the hind pipes, and consequently preventing further settlement. There was occasionally some difficulty encountered by the sard sliding from the sides of the trench, preventing-the divers getting at the underneath bolts ; however, this was obviated by pumping the sand from immediately about the joint with an 8-inch centrifugal pump placed on a scow.
The 48 and 60 inch pipes, which weigh in the neighborhood of six and eight tons each respectively, were rolled on skidways to the edge of the dock, where buttons or heads were fastened on over their ends with hook bolts, making them nearly water tight. They were then rolled off the dock, sinking only from one foot to a foot and a half in the water, and were thus floated out to position over the line in which they were to be laid. They were there held in sling chains from the side of a large scow, rigged with winches and tackle, until the heads were knocked off by turning the hook bolts, when they were lowered and shifted as required.
The 60-inch pipe is laid to such a grade that by closing a sluice gate at the island crib, or at its entrance, it can be emptied by pumping the well at the engine house low enough. This is not altogether the case with the 48 and 36-inch pipes, as they have a greater depression in a deep channel of the harbor than the bottom of the well, and, therefore, can only be emptied for about half their length. However, they can be shut off as desired, at the connecting crib, and also immediately outside the well, either both or one at a time, which will be found most necessary in cleaning the well, and during and after the construction of a new pumping house and well as contemplated by the department.
The part of this section of the conduit which cannot be emptied through the well will have to be syphoned, if it is found necessary to clean it from deposits of sand, etc., which, however, can hardly occur on account of the current caused by strutting off either of these smaller pipes, and using the other with the volume of water passing through the 60-inch pipe.
Figs. Nos. i and 2 show the details of the 60-inch pipe and flexible joints, the 48-inch pipes and joints being of the same material and construction, with the exception that they have no flanges. Fig. 3 gives the details of the connecting crib with its pipe connections ; the Island crib is very similar. Both cribs are built of 12 x 12-inch hemlock below water and white pine above, and are lined or sheeted in the inside chamber with 2-inch oak plank.
Early in 1891 a new pumping house and boiler room will be erected for the reception of two new 10,000,000-gallon pumping engines with their complement of boilers. When these are completed the city will be in a position of being supplied with 42,000,000 gallons of water per twenty-four hours, the full amount delivered by the conduit.