Patent GB-190523121-A (GB)
Title: Improvements in Hydraulic Elevators and other Hydraulic Apparatus
Inventor: FRASER ETHELBERT MEIKLE
Filed: 1905-11-10
Granted: 1906-10-25
Abstract: 23,121. Fraser, E. M. Nov. 10. Roots' - blower type. - Apparatus for proportioning the amount of water used from the supply main to the power required in hydraulic elevators and like machines comprises a rotary motor or pump of variable capacity coupled to another pump or motor of fixed capacity. The motors or pumps shown are of the rotary type, and special means are shown for varying the capacity of the variable member. Fig. 3 shows a sectional view of the motor or pump 20 of fixed capacity coupled with the pump or motor 21 of variable capacity, and Fig. 4 shows the general arrangement of-the whole apparatus including the hydraulic cylinder 22 of the lift or other apparatus. The pipe 27 connects the pressure main 24 with the side of the motor &c. 21 opposite to that on which it communicates with the pump &c. 20, and the tank 23 is also connected to the motor or pump 21. The pump or motor 20 is of ordinary type. Fig. 9 shows a sectional view of the variable pump or motor 21, and Figs. 10, 11, and 12 show vertical sections on the lines 10-10, 11-11, 12-12, Fig. 9. The pump or motor 21 comprises a pair of impellers 33, 34, which may be partly or wholly covered by rotatable cylindrical envelopes 37, 39. These envelopes are held in openings in frames 35, 36, which are of the form shown in Figs. 13, 14, 15, and 16. The impeller 33 is driven by or drives the rotary envelope 37, which is connected to the shaft 30 of the motor or pump 20 and is supported on the shaft 41 rotatably fixed to the piece 36. The impeller 34 is rigidly connected to the shaft 31 of the motor &c. 20. A rack 46 is connected to the piece 36, so that, as this rack is moved by a pinion mounted on the shaft 49 and operated by the wheel 48, the piece 36 is moved and carries with it the impeller 33 and the envelope 39 of the impeller 34, so that an inward movement of the rack conceals the impellers and restricts their operative surface, while an outward movement has the opposite effect. The impellers of the motor &c. 21 are longer than those of the motor &c. 20, and the corresponding impellers have their major axes in the same plane. The apparatus acts in the following manner :-Suppose the pressure of the water supply is 100 lb. per sq. in., and, at starting, the exposed surface of the impellers 33, 34 equals the area of surface of the impellers 28, 29, so that the whole apparatus is balanced. If the car is to ascend with its maximum load, the piece 36 is moved inwards to conceal the impellers entirely, so that the water flows freely through the motor &c. 20 into the cylinder 22. To stop the ascending car, the piece 36 is moved outwards, exposing the impellers 33, 34 which then exert a pumping action on the water flowing through the pipe 24 until the pressures have-become balanced on both sides of the motor 20. To lower the car with maximum load, the impellers 33, 34 are still further exposed until the motor or pump 21 acts as a motor driving the pump, or the motor 20 as a pump to pump water from the cylinder 22. When the car carries one-half the maximum load, the piece 36 is moved until about, but not quite, one-half of the effective areas of the impellers 33, 34 is exposed, it being understood that this area is less than the area of the impellers 28, 29. In this condition, the apparatus 21 acts as a pump, being driven by the apparatus 20 acting as a motor, and will deliver about one-half the quantity of water required for the cylinder from the tank 23. To stop the car, the piece 36 is moved until half the effective areas of the impellers 33, 34 is exposed, which has the effect of holding all the parts stationary. The car is lowered by still further exposing the impellers 33,34, so that the apparatus 20 is driven as a pump, half the water going back to the main and half to the tank. If there is no load on the car, the piece 36 is moved inwards until the exposed surface of the impellers 33, 34 is only slightly less than that of the impellers 28, 29. The apparatus 20 then acts as a motor and the apparatus 2t as a pump to pump almost all the water from the tank to the cylinder. To stop the car, the exposed surface of the impellers 33, 31 is made equal to the exposed surface of the impellers 28, 29. To lower the car, the exposed area of the impellers 33, 34 is made still larger so as to cause the apparatus 21 to act as a motor as before described.