The milking machine consists of two parts, a vacuum pump and a milking machine. The former mainly includes vacuum pumps, electric motors, vacuum tanks, vacuum regulators, vacuum pressure gauges, etc.; the latter consists of a milking bucket, a pulsator (or pulsator), a milk collector, a milking cup and some conduits and rubber hoses. Each milking machine includes 8 to 10 milking machines for milking 100 to 120 cows. The new type of pipeline milking machine has no milking barrel. The milk is passed from the milking cup to the milking device, and the pipe directly flows into the milk storage tank to completely isolate it from the outside; and the vacuum pressure of the milking cup can be automatically adjusted according to the milk flow. After being squeezed, it can be automatically detached, and it will not be "empty". The milk storage tank is made of stainless steel, the tank is sandwiched, there is a serpentine tube, and the refrigerant such as Freon No. 20 is used. There are two electric stirrers in the tank, which can quickly lower the temperature of the milk to 2~3 °C.
The milking machine has two types of two beats and three beats. In the early 1950s, China used three-beat styles everywhere, and now it uses two-beat styles. Its working principle is as shown in the figure: The two-beat type of so-called two-beat is that when the milking machine is started, it produces two beats in one beat. The first beat is a sucking beat. At this time, there is a vacuum in the nipple chamber and the wall chamber, and the rubber sleeve is in a normal state. Due to the pressure difference between the nipple tube and the nipple chamber in the nipple, the nipple sphincter is opened, the milk is sucked into the nipple chamber, and then flows into the milk bucket (or the storage tank).
The second beat is to squeeze the beat. At this time, the nipple chamber is still in a vacuum state, but the air is entered in the wall chamber. At this time, the rubber sleeve is compressed due to the pressure difference between the two chambers, the sphincter is closed, and the milk stops flowing. The purpose of the squeeze beat is to massage the nipple by pressing to restore blood circulation on the nipple that is suppressed during the sucking beat.
The pulsation frequency of the two-beat milking machine is generally 48 to 60 times/min. In a pulsating time, the ratio of sucking beats to squeezing beats is 1:1, which can also be adjusted to 2:8 or 3:7 or 4:6.
When milking with a two-barrel milking machine, the vacuum is always under the nipple, so that the nipple (ie the breast cup) will gradually touch the nipple and the breast. After squeezing for 3 to 4 minutes, although the milk has not been squeezed, but because of the nipple The communication with the breast is blocked, so that the milk discharge is stopped, and it is easy to produce the disadvantage that the milk is not easily squeezed out. But because there is no rest beat, the speed of milking is faster than the three-beat style.
Two-barrel milking machine When the vacuum between the inner casing and the inner casing is vacuumed, the milk is sucked out from the nipple tube, when the casing in the milking cup is vacuumed, and between the inner casing and the outer casing When it is not a vacuum, the nipple stops milking and rests. In normal operation, the inner sleeve is kept under vacuum, and the inner sleeve and the outer casing are controlled by the pulsator, sometimes vacuum, and sometimes filled with air.
2. In addition to sucking and squeezing two beats, the three-beat three-beat milking machine adds a third beat, that is, a rest beat. This makes it easy to eliminate the disadvantages of the two-beat milking machine. But milking is slower. The time spent on three beats in one pulsation is roughly: 45% of the sucking beat, 15% of the beat beat, and 40% of the rest beat.