US2086868A - Pulsator for milking machines - Google Patents

Description

July -13, 1937. s, H. HALL 2,086,868

PULSATOR FOR MILKING MACHINES Filed March 4, 1936 I s I Sela/e12 A. /z

45 by a bolt (not shown).

Patented July 13, 1937 PAiEsr OFFICE PULSATOR FOR MILKING MACHINES Selden H. Hall, Pcughkeepsie, N. Y., assignor to The De Laval Separator'Company, New York, N. Y., a corporation of New Jersey Application March 4, 1936, Serial No. 66,996

7 Claims.

9 My invention is an improvement in automatic pneumatically operated devices, commonly called pulsators, for producing and controlling the pneumatic waves or pulsations in the teat cups of 5 milking machines. V

The object 'of my invention is to provide a pulsator that is simple, inexpensive, positive and reliable in operation, with which there will be littlevariation in speed and with which the 10 pulsations will be balanced, that is, the duration of the high'pressure portion of the wave will be the same as that. of the low'pressure portion of the wave. f The reduction of'variation in speed is obtained 15 by complete elimination of friction as a control andreduction of other friction to a minimum; The equality of time for high and, low pressure portions of the wave is obtained by making all parts, both stationary and movable, 2O symmetrical about their center length so that the forces that cause movement in one directiontare equal to those that cause movement in the otherdirection. V r In an application No. 17,385flled April 20, 25 l935by JohnL. I-Iulbertis'disclosed a pulsator that is designed to accomplish the specified objects In this pulsator all valves are flexible members closingagainst rigid seats. In order to prevent leakage, two of these flexible members 30 must be mechanically held tightagainst their seats in spite of pneumatic pressures tending toforce them away from the seats. Suchtendency; if operative even in small degree, allows a slight leakage that interferes with the timing. The object of my'invention is to provide a construction whereby the flexible-members are so positioned that pneumatic pressures tend to force them against the mating rigid members.

In the accompanying drawing, which diagram- 40 :matically shows a longitudinal section through a pulsator embodying my invention in a preferred form, the body of the pulsator consists of a central piece a, two intermediate pieces b and b and two end pieces-c and c, all held together Through the central and intermediate pieces there is a bore surrounded by two rigid valve seats 03, d on the respective intermediate pieces and two flexible valve seats e, 6' held in counterbores in the fiofcentrakpiece a by rigid washers f, f abutting i 55 shown and, through restricted orifices i, i, with the air chambers inside the end pieces 0, c'.

The bore in the central piece a is in communication, through ports Hand I2, with the atmosphere. The central parts of the'bores in the intermediate pieces 2), b communicate, through ports i3, 13' respectively, with a chamber M in which a partial vacuum islmaintained,

Each of the end pieces 0, forms, with part of the space in the adjacent intermediate piece, an air chamber l5 or [5' having an opening I6 or 16, in alignment with the aforementioned bore' and around which there is a valve seat H or II and an annular space l8 or E8. These air chambers are separated from the bore by flexible non-permeable walls I9, I9.

In the bore there reciprocates a loose fitting valve carrier having two grooves that carry flexible (rubber) poppet valves 2|, 2!. The central part of the valve carrier 2!] is turned smaller, leaving rigid valves 22, 22'. Valves 2!, 2| 0 have a little play in their grooves. The central holes in valves 2|, 2! have an easy fit on the small diameter part of the carrier. When the carrier is at the left hand end of its stroke, as shown in the drawing, the outerpart ofvalve 2 2i fits against the seat d, and atmospheric pressure, entering between the valve and the adjacent side of the ring that forms the rigid valve 22, dishes valve 2! and forces it against the left-hand side of its groove, as shown, making an air-tight joint; the rigid valve 22' fits against the flexible valve seat e, and wall I9 is forced against the, seat ll.

The operation of the pulsator comprising the parts described above is as follows: With the valve carrier- 20 in the position shown, atmospheric air will flow through ports 12, II and the bore in the central piece past flexible valve seat e into pulsation chamber g and thence, through hole 72, toward a teat cup (not shown) and 40 slowly through the restricted orifice i into air chamber l5, wherein it will gradually raise the pressure against the flexible wall l9 pressing against the left end of the valve carrier.

At the same time air from the chamber l5 will flowslowly through the restricted orifice i and, from another teat cup (not shown), through the hole h into the pulsation chamber g" and thence,

and. the carrier 2!? begins to move toward the right. As soon as it makes a slight movement the flexible wall i9 leaves the seat ll and allows air to flow into the annular chamber l8 and so greatly increase the force toward the right that the valve carrier completes its stroke almost instantaneously.

In this movement of the valve carrier, valves 2| and 22 will leave their respective seats (2 and c and valves 22 and 2! will be forced, respectively, against the seats a and d, thus reversing the flow of air toward and away from the teat cups (not shown) and the air chambers i5 and i5, so that the pressure will gradually decrease in chamber l5 and increase in i5 until the carrier is driven toward the left and the cycle is completed.

From the preceding description it will be seen that when the carrier is at either end of its stroke the pneumatic pressure against the flexible valve 2! or 2! is in a direction to hold it against the rigid valve seat (1 or d and the pneumatic pressure against the flexible valve seat e or e is in a direction to hold it against the rigid valve 22 or 22, thus eliminating any tendency to leakage that might cause erratic action.

What I claim and desire to protect by Letters Patent is:

1. In a milking machine pulsator, the combination with a member having a bore with a number of valve seats therearound, all of which are poppet valve seats, a plurality of said seats being rigid and the remaining seats being yielding, of a second member adapted to reciprocate in said bore, yielding poppet valves carried by the second member and adapted to cooperate with the respective rigid seats and rigid valves carried by the second member adapted to cooperate with the remaining respective yielding seats, each of said members being symmetrical about its own center of length,

2. In a milking machine pulsator, the combination with a member having a bore with a plurality of poppet valve seats therearound, some of said seats being rigid and some of them yielding, and means providing, at each end of said bore, an air chamber, said means including a flexible non-permeable wall separating the corresponding air chamber from said bore, of a second member reciprocable in said bore, yielding poppet valves carried by the second member and adapted to cooperate with the respective rigid seats, rigid valves carried by the second member and adapted to cooperate with the respective yielding seats, each of said members being symmetrical about its own center of length, sources of higher and lower pressures, the areas of said valves being such that the net initial pressure, when the second member reaches one end of the stroke, is in a direction to hold it at that end, and passages, leading to said chambers, the flow through which is controlled by said valves and is in a direction to cause a reversal of the net pressure on the second member.

3. In a milking machine pulsator, the combination with a member having a bore with a plurality of poppet valve seats therearound, some of said seats being rigid and some of them yielding, and means providing at each end of said bore an air chamber, said means including a flexible non-permeable wall separating the corresponding air chamber from said bore, of a second member reciprocable in said bore, yielding poppet valves carried by the second member and adapted to cooperate with the respective rigid seats and rigid valves carried by the second member and adapted to cooperate with the respective yielding seats, each of said members being symmetrical about its own center of length, sources of higher and lower pressures, the areas of said valves being such that the net initial pressure, when the second member reaches one end of the stroke, is in a direction to hold it at that end, passages, leading to said chambers, the flow through which is controlled by said valves and is in a direction to cause a reversal of the net pressure on the second member, and means operative in the initial movement of the second member to admit a higher pressure to a certain area to increase the net force in the direction of movement.

4. In a milking machine pulsator, the combination of a body having a bore with poppet valve seats therearound, some of said seats being rigid and others yielding, of a member reciprocable within said bore, flexible valves and rigid valves, both carried by said reciprocable member, adapted for cooperation respectively with said rigid and flexible seats, air passages, sources of high and low pressures, and means providing two air chambers, one at each end of the bore, said means including flexible non-permeable walls closing the respective air chambers from the bore, each of said walls adapted to press against the adjacent end of the reciprocable member and adapted also, in either end position of said member, to be connected by said passages and valves, one with the high pressure and the other with the low pressure, each of said passages having a restricted portion.

5. In a milking machine pulsator a member having a single bore and provided with a central air inlet and on opposite sides thereof vacuum ports and between the central air inlet and each vacuum port a' pulsation port, said member having a rigid valve seat at one side of each pulsation port and a flexible valve seat at the other side of each pulsation port, a valve carrier reciprocable in said bore, and two pairs of poppet valves carried by said carrier, each pair of valves being positioned between the valve seats at opposite sides of one of the pulsation ports, one valve of each pair being flexible and adapted, at one end position of the valve carrier, to engage the adjacent rigid valve seat, the other valve of the same pair being rigid and adapted, at the other end position of the valve carrier, to engage the adjacent flexible valve seat, each flexible element specified being subject to air pressure, admitted through said air port, tending to hold it tightly against the corresponding rigid element specified when engaged therewith as specified.

6. In a milking machine pulsator, a member having a single bore and provided with an air port, vacuum ports and, on opposite sides of its center, with pulsation ports, a pair of valve seats, one rigid and the other flexible, adjacent each pulsation port, a valve carrier reciprocable in said bore, and valve mechanism carried by said carrier adapted, in one end position thereof, to connect one pulsation port with the air port and. the other pulsation port with one of the vacuum ports and, in the other end position thereof, to connect the second named pulsation port with the air port and the first named pulsation port with the other vacuum port, said valve mechanism comprising two pairs of valves cooperating with the respective pairs of valve seats, one valve of each pair being flexible and adapted, at one end position of the carrier, to seat against the other end position of the carrier, to seat against the corresponding flexible valve seat, each flexiblevalve seat projecting into a space around the carrier in constant communication with the air inlet and adapted, when engaged with the corresponding rigid valve, to be pressed thereagainst rocable in the valve cylinder, valve mechanism carried by the carrier adapted, in thereciprocation of the carrier, to connect each pulsation port alternately with the air inlet and a vacuum port,

said valve mechanism comprising a pair of valves on the carrier between its center and each end and a' corresponding pair of valve seats on the cylinder between its center and each end, one

valve of each pair being adapted to seat against one valve seat of the corresponding pair of valve seats when the carrier completes its movement in one direction and the other valve of said pair being adapted to seat against the other valve seat'of said pair of valve seats when the carrier completes its movement in the other direction, one of each of said two cooperating elements (namely, each valve and its seat) being rigid and V the other flexible, each of said flexible elements having an area in communication with the central air inlet when in engagement with its cooperating rigid element and being then subjected to the pressure of air in a direction tending to hold it against its rigid cooperating element.

SELDEN H. HALL.

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