MILKING MACHINES 337 



i. A vacuum pump operated by power, steam, electric motor, 

 gas engine, tread mill (bull), a head of water over thirty feet, etc. 



2. One inch iron piping connecting the vacuum pump with a 

 vacuum tank, supplied with gauge and safety valve, and thence 

 .about the barn for attachment to the milkers. 



3. The Milkers. — A milker consists of a milk pail (heavy enough 

 to withstand a vacuum), on which is placed a pulsator, which in its 

 turn is connected with one-half inch rubber tubing to four teat cups 

 fitted on the teats of the cow. 



The vacuum is about equal to one-half an atmosphere, fifteen 

 to seventeen inches, and the vacuum tank is connected with the 

 system to insure a uniform, safe and known suction. The pulsator 

 (Fig. 99) is the salient feature of this machine. It rests on top 

 of the milk pail, to which it fits tightly as soon as the exhaust is turned 

 on, because of atmospheric pressure and because it rests on a rubber 

 gasket. The pulsator is connected with the iron pipes which run 

 along over the stanchions (Fig. 98) by one-half inch rubber tubing 

 fitted to the nipple at its base. The two stop-cocks, seen in the plate 

 of the pulsator, are each connected with rubber tubes, one taking the 

 milk from the four teats of a cow on one side, and the other from the ; 

 cow to the other side of the pulsator. 



When the machine is in operation the cow's udder is cleaned, the 

 teat cups (of five sizes) are adjusted, and a milk pail — placed between 

 each two cows — is surmounted by a pulsator attached by rubber tub- 

 ing, both to the iron piping above, and to the teats of the cows on 

 each side (Fig. 98). That is, each milker (milk pail, pulsator, rubber 

 connections and teat cups) is capable of milking two cows at the same 

 , time. A stop-cock is turned and the suction applied by the pulsator to 

 the cow's teats. By this mechanism there is exerted intermittently 

 not only suction but also compression on the outside of the teat, simu- 

 lating the action produced in hand milking. Glass windows in the 

 tubing leading from the teats inform the operator as to the flow of 

 milk. Most cows do not object to the use of the machine. 



This machine will practically prevent the initial contamination of 

 milk, and will render the production of clean milk more simple and 

 easy than by any method heretofore known. But the greatest care 

 is necessary to achieve this result. 



