Patent GB-190710597-A (GB)
Title: Improvements in and relating to Apparatus for Automatically Operating Electric Switches for Starting and Stopping Electrically Driven Pumps
Inventor: TAYLOR JOHN
Filed: 1907-05-07
Granted: 1908-01-09
Abstract: 10,597. Taylor, J. May 7. Electrically - actuated pumps. - In order that regular pressure may be maintained in mains, the starting-switch of the motor working the pump is operated automatically by means of an hydraulic plunger which is released by a fall of pressure in the mains, an auxiliary device being provided whereby under abnormal conditions, such as failure of current, sufficient pressure may be produced to operate the plunger when the current is restored. Fig. 1 shows the main device with the switch off, Fig. 4 the whole apparatus with the switchwheel in the 'on' position but with the switch off owing to failure of current, and Fig. 3 the catch for operating the switch. A heavy plunger 8, which may slide in a tube 2 mounted in a cylinder 1, is attached to a chain 11 passing over a wheel 12 rotatably mounted, preferably on the spindle to which is attached the switch handle 30. The mains 6 are connected through a pipe 17 with a box 14 wherein is a diaphragm 15 secured to a rod 18 pressed by a spring 20. The rod 18 is loosely attached by a pin 23 to lugs 22 on spring 21 which serves to maintain the plunger in its raised position. The wheel 12 carries a self-tripping catch pivoted on a pin 21 and provided with a spring-pressed pin 28. When the pressure falls, the diaphragm 15 is pressed out and the rod 18 draws back the spring 21. The plunger 8 in falling forces water out at a regulated rate through a valve 5 and moves the wheel 12 round, the pin 28 carrying the switch arm 30 into its `on' position, where it is maintained by a holding-on magnet. The plunger continues its descent and moves the wheel 12 further round, the bevelled side of the pin 28 sliding past the switch handle 30, which is thus left free to move back to the 'off' position if the current supply fails. The pump increases the pressure in the mains until water passes through a valve 7 which is set to act at a desired pressure. Water enters the cylinder 1 and raises the plunger 8, which ultimately is engaged in its raised position by the spring 21. During the reverse rotation of the wheel 12, the spring pin 28 being rotatable about the pin 25 slips past the handle 30, which is subsequently freed and thus allowed to fly back to the 'off' position by means of a projection 31 fixed on the wheel. The auxiliary device consists of a tank 32 supplied by a ball-cock 33 and provided with a flushing siphon 34, the long leg 35 of which communicates with the cylinder 1. A valve 36 normally closed by a spring 37 is secured to a rod 38 having a core 40 and arranged to slide in a solenoid 39. A box 43 in communication with the mains is provided with a diaphragm 42 carrying a rod on which is an insulated spring 44 adapted to engage contacts 45, 46, connected to the solenoid terminals. When the current fails, the switch arm 30 moves to the 'off' position shown in Fig. 4, and owing to the fall of pressure in the mains the diaphragm 42 brings the spring 44 against the contacts 45, 46, thus completing the solenoid circuit. When current is again available, the solenoid 39 is energized and the valve 36 opened. The water is discharged from the cistern 32 and raises the plunger 8 to the position shown in Fig. 1. When the cistern 32 is empty, the plunger 8 falls and moves the switch to the 'on' position. The switch handle 30 if required may be worked by hand.