Bloede Dam - Power plant inside a dam

The first hydroelectric plant within a dam was built just south of Ilchester and Ellicott City on the Patapsco River in 1907. The underwater plant had windows behind the falls for light, but during rain when the "water is muddy" less light entered the room.

The dam was removed in 2018.
 

Maryland Inventory of Historic Properties info HERE

Removing Bloede plan and demolition video HERE

"Power Plant Inside of a Dam on the Patapsco River."  Electrical World.  August 3, 1907 --

"THE Patapsco Electric & Manufacturing Company, of Ellicott City, Md., has lately completed its new dam and power house on the Patapsco River near Ilchester, some 15 miles or more below Baltimore on the Washington Branch of the Baltimore & Ohio Railroad. The plant is unique in that it is placed within the dam and is thus completely under water. The plant also has the distinction of being the first of its kind ever built, and the cost is of course very much less than that of any other arrangement.  A view of the dam within which the power plant is placed is shown in Fig 1.

THE DAM  

The dam has a total length of 220 ft. and is 40 ft. wide at the base.  The height of the dam from normal tail water to the crest is 26 ½ ft.  At each end the buttresses and deck of the dam rise 10 ft. above the spillway as a protection from floods and to afford convenient entrances to the interior of the dam. The spillway is 168 ft. long and is provided with anchor bolts so that if at any time it may be deemed desirable, flash boards may be bolted to them and the available head increased two feet. The back water extends 54 of a mile with an average width of about 500 feet to the tail waters of a cotton mill located at Ilchester. The dam is built of reinforced concrete and the "deck" is supported by 19 buttresses 24 ins. thick at the bottom and 16 ins. thick at the top, which are placed 12 ft. apart. The mixture used was 1:3:6. The edges of the buttresses and of the openings are reinforced with 3/4-in. corrugated iron rods in groups of three. The shell of the dam is 18 ins. Thick at the bottom and tapers 10 10 ins. At the top.  The concrete in the deck is a 1:2:4 mixture reinforced with ¾ in corrugated iron bars at graduated distances down to 4 ½ in centers.  The apron extends only half way down from the crown, the remaining down-stream portion being entirely open and provided with windows by means of which the interior is lighted.  The shape of the apron is such that the water is thrown some little distance away from the windows. On a clear day the illumination is all that could be desired; while during rainy weather, at which time the water is muddy, the illumination is not quite so good. The view of the interior of the power house shows how much light is received through the windows beneath the falls.

At present only 108 feet of the dam is used for housing the power plant.  This part of the dam is fitted with a false ceiling hung five feet from the inside of the dam so as to protect the apparatus from any water that might seep through the outer shell of the dam.  The dam is built of a fine and rich mixture which was laid very wet.  Aside from this no precautions were taken to eliminate water.  The ceiling slopes until it reaches the vertical sides forming the power house. That portion of the dam not protected with the false ceiling is comparatively dry as very little water percolates through. What little water finds its way through the concrete trickles along the under side to the drain at the bottom. Were it not for this moisture a person within the power house would not be conscious that he was beneath the water. The waste water going over the crest of the dam is carried on the apron of the spillway to within 16 ft. of the tail water. This apron causes the water to fall about 20 ft. from the down-stream side of the dam and as the river bed is quite rocky at this point, no appreciable pitting takes place.

A fish ladder [wood trough in photo below] is placed at one side of the dam as required by law. This is 125 ft. long and has the proper slope and fins so that fish can easily go from the tail water to that above the dam. The wooden trough is shown at the entrance to one side of the dam. It might be well to state in passing that the reason for insisting on fish ways in dams is that when the fish spawn they go up stream to the head waters. To reach the waters above the dam they jump from fin to fin of the fish ladder until they reach the top.

POWER PLANT.

The power plant equipment consists of two 34-in. horizontal. Leffel water-wheels fitted with Woodward governors arranged so that either governor may control both wheels when the generators are operated in parallel. Each turbine runs at a speed of 240 r. p. m. and is direct-connected to an AllisChalmers 300-kw, 11.000-volt, three-phase. 60-cycle alternator.

Space has been provided for an additional unit of the same capacity.

Each alternator is provided with a 125-volt exciter belted to the shaft. The part of the dam used as a power house is, 108 ft. long, 10 ft. high and 27 ft. wide except at the buttresses where the width is 18 ft. The arrangement of the machinery is well shown in the engravings and in the plan and cross-sectional elevation of the dam. A concrete-steel floor is placed at a proper elevation above the lower pool between buttresses, the latter being increased in section below the floor. The hollow interior structure is built upon this floor, as indicated in Fig. 4.

The water is fed to the turbines through steel pipes passing through the up-stream spillway shell and discharged by draft tubes into the base of the dam, dropping into a well sunk some three feet below the river bed. The water passes thence by way of a channel constructed in the river bed, out of the dam. The intake is 5 ½ ft. below the crest of the spillway so that the trash racks arc kept clear of drift wood, etc. The trash rack is 10 ½  ft., and the flumes to the turbines 7 ft. in diameter. Two waste gates are placed near the bottom of the dam, the water from these passing under the floor. The flow through the feed pipe is controlled by a valve operated from the turbine chamber.

The mechanism for operating this valve is shown to the right in Fig 2 (below). The advantages of such an arrangement of water-wheel and generator are readily discerned. The dam foundation and structure are the power house: the chamber is free from moisture by reason of the free circulation of air around it and the development utilizes all the available fall.

The entire electrical installation is compact, secure, and of the highest efficiency so far as it can be obtained from flow and fall.  It will be appreciated that the water falls directly through the top of the dam into and through the wheels below, thus avoiding the friction and other losses of power resulting from carrying the water through long race ways to the wheels.

The difference between the present system and those already in vogue may be likened to direct-driven and belt-driven machinery.  The actual saving in power or what amounts to the same thing, the greater efficiency of the water will be approximately equal to the difference between belt and direct-drive.

The switchboard, which is located at one end of the power house, was built by the General Electric Company and is fitted with instruments.  As the exciters are arranged to be operated in multiple an automatic regulator is used for controlling the voltage of the generators.  Polyphase indicating wattmeters have been provided: one for indicating the street service and the other the total load.  A polyphaser curve-drawing wattmeter is also used for recording the total output of the station.

The leads to the generators and for the commercial and street feeders are fitted with distant control, oil circuit-breakers, with disconnecting switches.  The circuit breakers for the generators have time-limit relays so that in case of trouble on the outside feeders, they will not open before the others.  The switchboard is arranged so that there is no danger of shock to the operator at the board.  The voltage at the board does not exceed 125 volts, as the circuit-breakers, disconnecting switches, high-tension bus-bars, transformers, etc., are placed about eight feet from the front of the board with plenty of room for persons to make the necessary repairs without danger of coming in contact with high-voltage apparatus. The trans mission lines cover such a large territory, that it was decided to use 11,000 volt alternators in place of stepping up the potential by means of transformers.

When the plant is completed it will supply electricity for both lamps and motors. At present Ellicott City, Catonville, Irvington, Carroll, Halethrop, Arbutus, St. Denis, Elkridge and a part of West Baltimore are being supplied from the plant near Grays Mills. The territory covered is about six by ten miles and there is a considerable day load for that section of the country, about 250 horse-power. It is intended to extend the lines to West Arlington and Mount Washington, a distance of about 14 miles, when the new plant is delivering electricity. The old plant near Grays Mills has a capacity of 680 horsepower, of which 380 horse-powcr is generated by water. The electrical apparatus at this plant consists of one 240-kw Stanley generator and one 150-kw Allis-Chalmers generator.  Both generators are wound for 2200-volts, two-phase, 60-cycles and transformers are used to step the potential up to 11,000 volts.  At Catonsville, Wilkins Avenue and Beachfield Road.  Wilkins Avenue and Roland Road and at the city limits transformers are located for reducing the potential for distribution circuits. These are 2200-volt, single-phase lines except near the city limits, where, because of large motors installed, three-phase current is used. After the new station is in operation, it is the intention to use the old power house as a sub-station, as it is from this station that the different lines radiate.

Mr. Victor G. Bloede is president and general manager of the company and Mr. Otto Wonder is its superintendent. The designer and builder of the dam was the Ambursen Hydraulic Construction Company, of Boston, and H. von Schon, of Detroit, Mich., was the consulting hydraulic engineer. Messrs. Newton and Painter, of Baltimore, were the electrical engineers. The submerged power house was in this case the only feasible method of development on account of the available location and limitations of cost. A dam of this height is said to be the smallest that is available for a power house of this construction. At heights of from 40 ft. upwards details of submerged power houses, it is claimed, can be worked out to advantage and without the difficulty of restricted space.

©2017 Patricia Bixler Reber
Forgotten history of Ellicott City & Howard County MD