Patent GB-117257-A (GB)
Title: Improvements in and relating to Pulsating Mechanism.
IPC: A01J5/10
Filed: 1918-06-17
Abstract: 117,257. Empire Cream Separator Co., (Assignees of McCornack, H.). July 2, 1917, [Convention date]. Vacuum engines.-In a pulsating apparatus for cow-milking machinery and for other purposes, vacuum or compressed air is admitted to a chamber alternately with air at atmospheric pressure, the action being controlled and regulated by means of valves actuated by a further pressure-operated member, this member having an initial resistance to movement greater than its resistance to continued movement after such initial resistance has been overcome, the actuation of the valves being thereby rendered quick and decisive. Different forms of the device are shown in Figs. 2 and 7, applied to cow-milking apparatus. In each of the forms shown, the vacuum pipe 7 leads to a vacuum chamber 50 in the pulsator casing 30, which may comprise a casting, as shown in Fig. 7, or a drawn metal shell with a core, as shown in Fig. 2. Communicating with the chamber 50 is a chamber 52 leading to the teat cups through the nozzles 24 and adapted to be placed in communication with the atmosphere by a valve 67. Communication between the chambers 50 and 52 is controlled by a valve 65. The valves 65, 67 are operated by a rod or plunger 49 slidably mounted in a plug 46 screw-threaded into the base of the pulsator casing 30, the vacuum valve 65 being supported on a spring 66 bearing against a collar 48 on the rod, whilst the end of the rod has a lost-motion engagement with the air valve 67. A perforated cap 70 prevents displacement of the valve 67 and is provided with a rotatable cover enabling the size of the air openings to be adjusted. In the positions shown in Figs. 2 and 7, the vacuum valve 65 is open and the chamber 52 is exhausted. When the valve rod 49 moves up, the valve 65 is first closed, then the valve 67 is opened, admitting air. In the form shown in Fig. 2, the means for operating the valve stem 49 comprises a flexible diaphragm 40 secured within an extension 34 of the pulsator casing 30 forming a chamber 36. The under surface of the diaphragm is in continuous communication with the atmosphere by means of a groove 43 in the base 42, whilst the upper surface communicates with the chamber 52 through a passage 56, 58 throttled more or less by a valve stem 59. Thus when the chamber 52 is in vacuum the air above the diaphragm is regulably exhausted through the passage 56, 58 until the excess pressure of the air underneath overcomes the resistance of the diaphragm and reverses its convexity. The valve stem 49 is thereby lifted to close the valve 65 and to open the chamber 52 to air by lifting the valve 67. Air then returns to the chamber 36, whereupon the diaphragm returns to its criginal shape. The action continues automatically to long as the pipe 7 is in vacuum. In the arrangement shown in Fig. 7, the flexible diaphragm is replaced by a piston 81 on an extension of the valve stem 49, the initial resistance to movement being produced by spring-pressed balls 84 housed in the casing and adapted, when the piston is in its lowest position, to engage a groove in the periphery thereof. In this arrangement, the under surface of the piston is open to air, the piston being pressed down by a spring 83. When the chamber 52 is in vacuum, the air above the piston is exhausted, eventually serving to raise the piston and to reverse the valves. A modification is described in which valve casings, as shown in Fig. 2, are placed on each side of the diaphragm, being arranged to act alternately and to actuate the diaphragm positively in both directions. In this form, the pulsators may be connected so as to operate the teat cups alternately in pairs. The throttling valve 59 is adjusted by means of a handle 61 and may be slightly bent to increase the grip of the screw-thread. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a modification in which the device is adapted solely for producing reciprocating motion, the teat cup connexions being eliminated and the valve stem 49 extended to form the reciprocating member externally to the pulsator casing. This subject-matter does not appear in the Specification as accepted.