Patent GB-396409-A (GB)
Title: Improvements in pulsators for milking machines
IPC: A01J5/14
Filed: 1932-02-02
Abstract: 396,409. Cow-milkers; electricallyactuated valves ; vacuum pumps and gauges. DAVIS, C. A., Don Street, and STEMPA, F. A., Ross Street, Collingwood, both in Invercargill, Southland, New Zealand. Feb. 2, 1932, No. 3146. Convention date, Aug. 3, 1931. [Class 84.] An electrical pulsator for a milking-machine is so arranged that the periods of suction are of longer duration than the periods of release. The pulsator comprises a solenoid 4A, Fig. 3, actuating a valve 5 slidable therein, the valve coacting with an atmospheric port 6A and a port 7A opening into a milk pipe 9 which is maintained under vacuum. When low voltages are used, the valve 5 is made of iron or steel, but for use with high voltages, the valve comprises a steel body provided with conical ends 5B of soft non-ferrous metal to avoid trouble due to residual magnetism. The iron or steel casing 6B of the solenoid is provided at the bottom with an iron or steel member 6C which, together with the valve 5, form a magnetic circuit. The port 7A is formed in a fitting 8 supporting the pipe 9, the fitting being provided with a branch pipe 8A opening into the upper face of the fitting adjacent the port 7A and communicating with the outer chambers of the teat cups and with a branch pipe 8B opening into the pipe 9 and connected to the inner chambers of the teat cups. The pipe 8B is thus constantly under suction, whilst suction and atmospheric pressure are alternately transmitted to the pipe 8A as the valve 5 reciprocates. Current is supplied to the solenoid through a distributer 11, Fig. 5, comprising a series of contacts 11G engaged by a wipe contact member 11T rotated through worm gearing, driven e.g. from the vacuum pump. The circular length 11K of the contact-making portion of the member 11T is greater than the circular length 11L forming the contact-breaking portion, the lengths being preferably in the ratio of 60 to 40, which is a suitable ratio for the periods of suction and release. The contacts 11G are each connected to a pulsator, one of which 14, Fig. 7, is utilized to operate a milk releaser. The releaser comprises inner and outer tapered chambers 13B, 13C between which is an annular space 13D, the chambers being closed at the lower ends by clock valves 13E, 13F. Vacuum is transmitted to the inner chamber 13B, and hence to the milk pipe 9 which opens therein, through a conduit 14D and a vacuum pipe 14A, whilst vacuum and atmospheric pressure are alternately transmitted to the annular space 13D, and hence to the outer chamber 13C, through a duct 14E which, by the reciprocation of the valve 14G of the pulsator, is alternately put into communication with an atmospheric duct 14J and a duct 14C opening into the vacuum pipe 14A. The Specification as open to inspection under Sect. 91 comprises also (1) a teat cup in which the outer end of the casing 10E, Fig. 12 (Cancelled) is provided with a beaded edge 10G, the end of the liner 10A being folded back over the beading and secured by a push-on cap 10H having a tapering recess terminating in a groove 10L ; (2) an oil filter mounted on the outlet pipe of the vacuum pump, the filter comprising a gauze cone the base of which rests in an annular recess in the filter casing, the recess being connected by a drain pipe to the work. ing parts of the pump, and (3) a vacuum gauge and a spring-loaded air inlet valve 15E, Fig. 11 (Cancelled), mounted on the milk pipe 9, the conduit 15H leading to the vacuum gauge opening into the conduit 15D connecting the air inlet valve to the pipe 9, so that air drawn through the conduit 15D exerts an ejector action on the conduit 15H and prevents milk vapour in the pipe 9 from gaining access to the vacuum gauge. This subject-matter does not appear in the Specification as accepted.