From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Descriptive document on the operation, installation, and application of the Autopulse electric fuel pump.
| Identifier | ExFiles\Box 41\1\ Scan010 | |
| Date | 23th September 1925 guessed | |
| Page 10: applied, the tungsten contact at (11) is held in contact with another tungsten contact (not shown in drawing, but can be seen in the view having the cover removed) by the delivery spring action. The contact pressure is high in the rest position of the armature and it is maintained high throughout the suction stroke by the magnetic action of the breaker. A sleeve of steel (12), which is attached to the spring (11) and is centrally located in the hole through the steel core of the magnet (16), tends to move upwards with force toward the armature (10), thereby stressing the spring (11) and holding the contacts under pressure until the armature, which is pulled toward the magnet, hits the spring (11) and forces the contacts apart. A quick break is produced by the spring movement due to "set up," after the magnetic stress is removed from the spring (11). The armature (10) is pivotly attached at its center to the expansible pumping element or bellows (3) and the action just described completes the suction stroke by expanding the bellows. This action draws fluid from the supply tank through the threaded opening (2), through slots around the underside of the cap screw (8) which contains the closed air-chamber (17), through screen (7) and monel disk valve (6) into the bellows (3). (Note the arrows). Valve (6) closes as the armature begins its delivery stroke, powered by the energy stored in the calibrated driving spring (14), which collapses the bellows (3), driving the liquid out through valve (4) and opening (1) until the armature travel brings the contacts together again. If the passage is filled with liquid and the outlet is restricted, the enclosed liquid will prevent the bellows collapsing and the next suction stroke will be prevented until some of the liquid escapes. This action constitutes the control. The driving spring (14) and the magnetic shell (15) are held in place by the gasketed cap screw (13) and the shell and the bellows are sealed against gasoline leakage by a cork gasket. The shellaced fiber gasket (9) seals cap (8). Referring to the illustration having the shell (15) removed (page 4), the electrical circuit is as follows: Battery to switch (not shown), switch to rubber-covered binding post on base, down through the screw in the insulated spacer sleeve to magnet wire terminal upon the underside of the fiber spool head and under the screw head, through the magnet winding to the insulated contact held in place by said screw and sleeve, through breaker spring, armature, base casting and to the battery, through fuel pipes and engine or directly by wire. The length of stroke of the armature is from .025" to .030" and is determined or controlled as to length by the position of the spring (11), not stressed, in respect to the armature. About 5,000 strokes are made to the gallon of fuel and at the rate of 800 to 1,000 per minute, maximum capacity. In pumping air the length of stroke is doubled and the speed about 2,500 per minute. When the armature comes to rest, with no pressure within the bellows, it has taken a position much higher or traveled farther than it does during stroking. This greater or surplus travel represents set-up pressure for the contact. That is, if electrical contact is not established at the end of the normal stroke or when the "points" touch, the travel of the armature will be continued for a distance of two or three times the stroke or until the electrical resistance is broken down. The contacting is further assisted by a slight rubbing action due to the mounting of the contacts at an angle to their travel. [Image Caption] Cut-away prospective Actual size WHEN a PERMANENT HYDRAULIC PRESSURE is established, as, for instance, by mounting the AUTOPULSE below the carburetor or other delivery point, this "set-up," or pressure upon the contacts, is reduced. A permanent head of two feet of gasoline upon the delivery side would reduce the FACTOR of SAFETY in MAKING CONTACT by nearly one-half. This reserve contact pressure, or "follow-up," is an important feature. It is needed in emergencies for breaking down the resistance which may be introduced by oxidation or other interferences. Under proper conditions, this "follow-up" is sufficient to prevent open circuit failure until the tungsten is entirely gone from the contact points. Page 11: MARINE APPLICATION As all the fuel feed systems, viz: gravity, air pressure, vacuum tank and water suction, have proven unsatisfactory, especially IN SPEED BOATS, for one reason and another, the AUTOPULSE SYSTEM has been enthusiastically received by owners and boat builders alike and is rapidly being adopted as standard equipment. It is also replacing or supplementing all other systems. The AUTOPULSE CAN BE INSTALLED AND FORGOTTEN. The AUTOPULSE was well represented in the 1924 speed boat races upon the Detroit River. Although AUTOPULSE production was hardly started at the time, seven of the boats were equipped and every one went through this gruelling test perfectly, including the winner of the Junior Gold Cup Race. The AUTOPULSE is sealed and will not be internally affected by corrosion. The aluminum base casting will be protected at the threads if the fitting is coated with shellac before screwing into the outlets. Care should be used not to get shellac upon the outlet valve at "C." The units intended for marine use are black, having been entirely immersed in "Duco" varnish after being otherwise completed. This finish is not "cut" by fuel oils and, therefore, will not be removed by them, exposing the aluminum surface to the action of salt water. In case it is desirable to change the color or further protect the AUTOPULSE by painting, care must be used not to CLOSE THE VENT. This is a small hole located in the center of the bolt head at the bottom of the case. SPECIAL APPLICATIONS FLUIDS MAY BE ELEVATED TO ANY HEIGHT DESIRED. There are many problems, as to LIFTING FUEL or OTHER LIQUIDS, which may be solved by the use of the AUTOPULSE. The AUTOPULSE UNIT or MULTIPLES CAN BE USED IN SERIES with OTHER UNITS or MULTIPLES to increase the height to which fluids may be elevated. The delivery side of the lowest pump is connected into the suction or "T" side of the next higher, etc. All electrical connections are brought to a common switch, and the return circuit is made through the pipe. The voltage must be (6V or 12V) from a battery circuit. The circuit should be closed upon all pumps, piped in series, simultaneously. The distance apart, for placing the units, will depend somewhat upon the specific gravity of the fluid. For gasoline, it may safely be 4 or 5 feet. The top pump should always be at the level of the delivery point. In case the outlet is restricted, the control of the series is the same as that of a unit. There is no metal in the AUTOPULSE which will be corroded by fuel. Viz: Aluminum, brass, monel and solder. The monel valves may be changed to brass if required. This combination of metals will not permit the use of a liquid which would become an electrolyte and cause corrosion. The bellows is .004" thick and will stand a pressure of 20 lbs. per square inch without distortion. [Logo] IMCO | ||