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The Bristol Hippodrome Stage, its Machinery and Mechanical Equipment - By F. G. H. Macrae

From the Stage Yearbook of 1916

Bristol Hippodrome - Bristol Index

THE music-hall of to-day commands serious consideration from the engineering world. The advancement it has made in mechanical equipment permits of productions being presented to the public which, in olden times, would have been considered impossible. Realism in olden times depended on imitations such as transparencies for waterfalls, etc.; realism of to-day is presented in its literal meaning. To attain this, modern machinery is now utilised to the best advantage, and the Bristol Hippodrome presents one of the finest illustrations of a modem music-hall equipped with a mechanical installation that assist the stage manager to the last degree. To transform an ordinary stage into a lake of water by the movement of two levers can justly be considered the acme of scientific application, and the release of thousands of gallons of water from the roof permits of effects both realistic and astounding.

The Bristol Hippodrome's stage - Showing back stage lifted, front stage drawn under, bays open, glass screen partly raised, and water tank exposed.

Above - The Bristol Hippodrome's stage - Showing back stage lifted, front stage drawn under, bays open, glass screen partly raised, and water tank exposed.

The Bristol Hippodrome stage may broadly be described as being on the hydro-electric principle; part of its machinery being hydraulic and part electric. This is still more interesting when it is known that the hydraulic pressure is "made on the premises," and the same applies to some extent to the electric, although in the latter case the primary source of supply is the Corporation mains. Productions such as "Sands o' Dee," "Redskins," "The Flood," "Mexico," etc., with their raging torrents, waterfalls, storms and diving animals present no difficulties in a house fitted out on these lines. Scenes of river life, with the gay decked throng in punts and canoes, have been presented in all their realism, and there is practically no limit to which such an equipment can be adapted. Ability and enterprise are the keynotes of such an attainment, and Mr. Oswald Stoll is to be congratulated on this fine building.

Stage and Water Tanks

A corner of the water tank, showing three of the four tables, bay and horse rake, front and back stage, and table ropes and pulleys.

Above - A corner of the water tank, showing three of the four tables, bay and horse rake, front and back stage, and table ropes and pulleys.

The stage has a depth of 60 feet from footlights to back wall. The proscenium opening is 47 ft. 6 ins., and the width from wall to wall is 81 ft. A scene dock is provided back stage prompt. From a mechanical point of view the stage may be considered as being in two halves—front and back. The back half is lifted through the medium of a 4-in. steel wire rope, operated by an 8-in. hydraulic ram, controlled from the switchboard.

Under the main water tank, showing three of the four hydraulic rams for operating the tank tables.

Above - Under the main water tank, showing three of the four hydraulic rams for operating the tank tables.

The front half, together with the footlights, now travels back on steel rails until underneath the back half. This is accomplished by means of a worm gear, which operates a shaft and drives two sprocket wheels and chains; the whole being driven by an electric motor. The footlights are turned down level with the front stage by means of a handle operating a small worm gear, and they are electrically disconnected by means of a plug in the basement. This discloses the main water tank, 42 ft. by 27 ft. 6 ins., with a maximum depth of water of 7 ft. 6 ins. At the P. and O.P. sides are two bays, each 7 ft. 9. ins., by 10 ft. 6 ins., the stage portions of which open by means of a hand winch. These provide a useful entrance or exit to or from the tank. Rake pieces are sometimes fixed to the table directly under these bays, which are of great assistance to animals leaving the water. Situated in the tank are four tables completely covering the bottom. These tables are capable of being raised to any height up to the top of the tank, and will, therefore, provide either a dry platform or any depth of water up to the maximum. Each table is capable of being moved independently by its own 8-in. hydraulic ram; the power being transmitted to the table by four 2½-in. steel wire ropes operating over pulleys.

The Motor driven Three-Ram Pump and Hydraulic Accumulator.The tables are controlled from the switchboard by four wheel valves and a master lever. In front of the tank, is a glass screen consisting of seven sections of 1-in. plate glass. This is capable of being raised to a maximum height of 6 ft. above the level of the tank, and prevents any water from splashing over into the orchestra. This screen is operated by a 4-in. hydraulic ram controlled from the switchboard.

Left - The Motor driven Three-Ram Pump and Hydraulic Accumulator.

The water in the stage tank is heated through the medium of a cast-iron sectional boiler. On the stage roof are situated two water tanks for "effects." The water from these is led to the stage by 8-in. pipes, and controlled from the fly "bridge" by two wheel valves. This water eventually runs to a sump under the stage tank and is pumped out by an electrically driven centrifugal pump.

The Motor Driven Centrifugal Pump.Water mains are also available in the "flies" and "grid." The water to the stage tank is supplied by a 4-in. main, and the tank is emptied into the basement sump through a 6-in. pipe and wheel valve. This water is then pumped to a drain by means of the centrifugal pump before mentioned.

Right - The Motor Driven Centrifugal Pump.

The Hydraulic System

The nucleus of the hydraulic system is the hydraulic accumulator - or compressor - by which water is raised to a pressure and conveyed by pipes to the various rams. This consists of the accumulator and a three-ram hydraulic pump (electrically driven), which supplies eight rams at a pressure of 1,000 lbs. per square inch. The rams in turn operate the back stage, four tank tables, glass screen, tableaux curtains, and fireproof curtain.

The Chain Wheel and Gear for Driving Front Stage.The 8-in."back stage" ram is placed horizontally in the floor of the stage basement. The four 8-in. rams for the tank tables are situated horizontally under the stage tank, and the ram for the glass screen is in a vertical position in front of the tank. The 5-in.. tableaux curtain ram and 6-in. fireproof ram are situated on the wall above the fly-level, P. and O.P. respectively. Emergency gear is fitted to the fireproof curtain, which enables this to be raised by hand. Other emergency gear in the shape of heavy block tackle, spare armatures, and numerous spare parts, are instantly available.

Left - The Chain Wheel and Gear for Driving Front Stage.

The Electrical System

The Back Stage Hydraulic Ram, and Front Stage Motor.The electricity supply for the stage is taken from the Bristol Corporation. The lighting is alternating current, single phase, 210 volts. The power is 500 volts D.C. The stage intake-rooms is between the stage and basement levels, the main circuits being controlled by Berry-Skinner switches.

Right - The Back Stage Hydraulic Ram, and Front Stage Motor.

The Vertical Turbine Vacuum Cleaner.Apart from the ordinary stage lighting the electric system consists of a motor driving the three-ram pump, a motor driving the front half of stage, an electrically driven centrifugal pump, an electrically driven vacuum cleaner, and two motor generators.

Left - The Vertical Turbine Vacuum Cleaner.

All these motors are of the D.C. type and run at 500 volts. The motor generators supply the bioscope and stage arc lighting at a pressure of 80 volts. They consist of two machines; one with an output of 250 amperes, and the other with an output of 280 amperes. They are situated in a room between the stage and basement, and feed a separate board on the main-switchboard, from which the various arc circuits are controlled. The three-ram pump motor, centrifugal pump motor and vacuum cleaner motor are all in the stage basement; the first has a speed of 965 R.P.M., and transmits its power through gearing. The latter two are direct coupled. The centrifugal pump motor runs at a speed of 1,600 R.P.M., and the speed of the back stage motor varies according to the position of the controller, which is situated on the main switchboard. The vacuum cleaner is of the vertical turbine type, and runs at 3,500 R.P.M.

The Two Motor Generators for the Arc LightingThe Power Board Motor Generators, and Spare Armature.

 

Above - The Two Motor Generators for the Arc Lighting, and the Power Board Motor Generators, and Spare Armature.

The Switchboard

The Main Switchboard.The main switchboard may be described as consisting of the stage lighting board, arc board, hydraulic levers and front stage electrical controller. The lighting board is fitted with liquid dimmers, which can be operated together or independently. The pots are situated on the lighting gallery directly behind the board, there being ample room for accessibility. The incandescent lighting of the stage consists of seven battens, proscenium lights and floats, together with lengths and bunches.

Right - The Main Switchboard.

The stage arc lighting consists of six automatic arcs (four being of the flame type), together with the ordinary hand-fed -arcs on the perches and stage. There is also provision for three arcs from the auditorium. The stage has provision for a total of twenty-five arc lamps. A novel feature of the stage arc lighting is a lighting gallery immediately behind the top of the proscenium which permits a fine concentration of light; this is particularly useful for illuminating the water. A table indicator has been installed by Mr. Campbell, the resident electrician, which indicates on the board the height of the tank tables, thereby enabling the operator to know the position of these, and consequently the depth of water.

Prompt Corner, showing Signal Board, Hydraulic Levers, and Number Regulator.This indicator is in the form of weights fixed to a small steel wire rope, which in turn is connected to the rope of the table. The weights move vertically on a scale on the switchboard wall, and the depth of the water is shown in feet. The hydraulic levers for the "tabs," and "fireproof," and the signal board are situated in the prompt corner. The signalling system consists of lights, bells, and telephones; and a second signal board is available for large productions consisting of coloured lamps wired in series. Two 100 ampere "special effect " boards are provided on the stage for any electrical effects requiring a large amount of current. The circuits feeding these boards are entirely independent of any other stage circuit. Each board is fitted with three D.P. switches and fuses.

Left - Prompt Corner, showing Signal Board, Hydraulic Levers, and Number Regulator.

Heating

The heating of the theatre is on the low-pressure hot-water system, and consists of radiators and pipessituated at points calculated to give the maximum efficiency, and governed by a cast-iron sectional boiler. There is also a sectional boiler for heating the water in the main stage tank, and a separate boiler for supplying the water to the dressing-rooms.

The above text and all of its accompanying images was first published in the Stage Yearbook of 1916 - Courtesy Roger Fox.

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