Patent GB-733395-A (GB)
Title: Improvements in apparatus for measuring and dispensing liquids
IPC: G01F11/28
Filed: 1953-07-14
Abstract: 733,395. Dispensing measured quantities of liquid. HOLMBERG, E. W., and WESTLIN, L. P. E. July 14, 1953 [July 17, 1952; June 5, 1953], No. 19568/53. Class 106 (5). [Also in Group XL (b)] An apparatus for measuring and dispensing liquids includes at least one measuring and dispensing receptacle 1, Fig. 1, connected through a conduit 3 to a liquid supply container 4 and conduits 15, 16a, 16b and 19 with a vacuum source 22 and an atmospheric pressure source 18, valve means 17, 21 and 27 being operated in a predetermined sequence to cause liquid from the container 4 to be drawn into the receptacle 1, to cause excess liquid to flow back into the container, and to actuate a dispensing valve 7. The apparatus may be operated by inserting a coin or token in a mechanism 28 to close a contact 28a, Fig. 2, and energize a relay 29 which closes a holding circuit 29a and a contact 29b, to energize relays for the valves 21, 27, and opens a contact 29c to disconnect a relay for the valve 17. The receptacle is thus connected to the vacuum source 22 and the valves 7 and 17 are closed so that liquid is drawn through an undulated or notched edge 6 on the conduit 3 into the receptacle 1 until it contacts a depending portion 9 or an electrode on the lid 8 of the receptacle to energize a relay 31 which closes a holding circuit 31a, opens a contact 31b to close the valve 21 and a contact 31d to open the valve 17 so that liquid flows out of the receptacle, which is now at atmospheric pressure, until its level is flush with the top of the pipe 3. A time relay 32, energized by the relay 31, now open circuits the latter and the relay 29 to open the valve 7 and restore the apparatus to its initial condition. The valve 7 is operated by a control unit 26 and comprises a ported, frustoconical body spring-pressed into engagement with its seat. Several valves connected to the receptacle at different levels and adapted for selective operation may be provided to enable the measured quantity to be varied. The relays are supplied with a low voltage, say, 24 volts, by a transformer 30 and the lid 8 is insulated from the receptacle 1 by a rubber sealing ring 10 with which it is held in contact by clip members (not shown). Electrically non-conductive liquids may be measured by inserting a conductive float member in the receptacle or by manufacturing the latter or parts of it from transparent material and providing a photo-electric cell (see Group XL (b) ) to sense the liquid level. Preferably, however, a receptacle 1, Fig. 3, operating with a conductive liquid is used to control a number of measuring units 10a, 10b and 10c connected to the same vacuum and atmospheric sources as the receptacle 1. The units may have different capacities and be provided with adjustable choke valves 52a, 52b and 52c to ensure that they are filled to the appropriate degree simultaneously. A common liquid supply container may be used. Fig. 4 shows an arrangement in which the dispensing-valve control is connected to a conduit 35a, the measuring receptacle to a conduit 35b, the vacuum source to a conduit 31, and the atmospheric pressure source to a conduit 33 while four valves A, B, C and D operated by a cam shaft control the measuring cycle. Initially, the valve A is open and the valve B closed to connect the dispensing valve control to the vacuum source so that it closes whereupon valve C is opened and valve D closed to connect the receptacle to the vacuum source until it fills with liquid when the settings of these latter valves are reversed to connect the receptacle with the atmosphere. The measure quantity is now delivered by reversing the settings of the valves A and B controlling the dispensing valve. The valves may be formed by four vertical bores 77, Fig. 10, in a common block 61, each bore having a seat 79 to co-operate with a valve member 78 reciprocated in a guide 90 by a bellcrank lever 72 and a cam 67. The latter comprises two parts which can be relatively adjusted and then secured by a screw 69 to permit the period for which the valve is held open or closed to be adjusted. The cams are mounted on a shaft 62 driven by an electric motor. Fig. 14 shows a measuring receptacle 43 into which liquid is drawn through a conduit 42 until it contacts one of a number of selectively-operable electrodes 46, 47 when air is let into it in the manner already described and a valve 45 rotated to dispense the liquid through an outlet 48. The valve may be operated by a pneumatically-driven rack and pinion. The measuring receptacle may also be constructed with a pneumatically-operated, balltype dispensing valve and with a suction pipe of D-shaped cross section which ends flush with its side wall.