Vacuum installation for machine milking. Review of milking equipment: differences and modifications of milking machines and installations Developments of vacuum wires in a milking installation
The invention relates to agriculture, in particular to vacuum installations for milking machines. The installation contains a pump, discharge and suction pipes, a circular manifold, a suction pipeline, a nozzle, a liquid tank, and an electric motor. To increase the efficiency of the pump, coolant is sucked through a pipeline through a nozzle and supplied to a circular manifold. Using a circular manifold, it is evenly distributed throughout the entire volume of the suction pipe. This will cool the pump more efficiently and reduce fluid consumption, increase pump performance and the amount of vacuum created, which increases the efficiency of milking machines. 3 ill.
The invention relates to agriculture, in particular to vacuum installations for milking machines. The unified vacuum installation UVU-60-45 is known, passport UVA.OO.OOO PS, ed. 6, 1981, which is intended for machine milking in milking machines. However, the use of air cooling and a lubricating fluid supply system does not give the desired effect. Vacuum pumps are known in which the working part of the rotors is made of textolite, for example the PTK brand. However, as experimental studies have shown, when the pump is operating, the textolite cannot withstand heating temperatures above +90C. (Volkov I.E. Research and development of a milking machine with an individual vacuum source. Dissertation for Candidate of Technical Sciences, Kazan Agricultural Institute. - Kazan, 1974 ). However, the use of air cooling does not give the desired effect. Therefore, for cooling, it is advisable to inject a liquid-air mixture. The purpose of the invention: to increase the efficiency of a vacuum installation by ensuring a dosed supply of coolant and its uniform distribution in the working chamber. This is achieved by the fact that the suction cavity of the pump is equipped with a system for supplying coolant mixed with a gas flow .Figures 1 and 2 show the proposed vacuum installation, and figure 3 shows a circular manifold. The vacuum installation consists of a pump 1, a discharge pipe 2 and a suction pipe 3, a circular manifold 4, a suction pipeline 5, a nozzle 6, a liquid tank 7 and electric motor 8. The principle of operation of the vacuum installation is as follows. When pump 1 is operating, under the influence of the vacuum it creates, liquid is sucked in in doses through the suction pipeline 5 through the nozzle 6 from the liquid tank 7. Then it enters the circular manifold 4, with the help of which it is evenly distributed throughout the entire volume of the suction pipe 3. A uniform supply of liquid mixed with a gas flow in the pump suction cavity allows for more efficient cooling of the pump, reducing liquid consumption, increasing pump performance and the amount of vacuum created. In addition, the supply of coolant improves the coefficient of friction of the rubbing pair of the working part of the pump rotors.
Claim
A vacuum installation for machine milking, containing a vacuum-creating pump with suction and discharge pipes and electric motors, characterized in that it is equipped with a system for supplying coolant mixed with a gas flow into the suction cavity of the pump, consisting of a liquid tank, a suction pipeline with a nozzle in the intake parts having a calibrated cross-section for dosed suction of liquid from the tank, and a manifold at the inlet to the suction pipe of the pump, ensuring uniform distribution of liquid throughout the entire volume of the suction pipe.
Vacuum systems
Vacuum production is one of the key points for the correct functioning of the milking machine. Vacuum generating and control systems must guarantee the protection of animal health.
Vacuum is used at different stages of milking:
- Movement of milk during milking
- The operation of vacuum pulsators, which guarantee massage movements in alternating phases
- Pumping milk through a milk pipeline into a cooling tank
- Ensures the operation of valves in many parts of milking equipment.
Milking equipment must have an appropriate, stable and uninterrupted vacuum level to avoid overstimulation of the teats. Thanks to special production procedures and strict control of Milkline, vacuum pumps guarantee, with equal power consumption, high flow rates without compromising the reliability and durability of milking equipment. Milkline vacuum systems can meet the requirements of any milking system. Compact and practical design Milkline installations “allows for easy installation and maintenance vacuum stations.
Vacuum stations are divided into three groups:
— Oil-free/dry paddle units with capacity from 150 to 250 liters per minute. This is the simplest type of vacuum stations and they are used in small farms. The vacuum pump does not require oil at all and the consumable part in such pumps is just graphite plates/pump blades, which wear out and are replaced as needed. The normal service life of blades is 3-4 years. Such installations are installed on mobile milking machines, which can simultaneously serve a maximum of 2 heads. Or you can design your own stationary milking machine yourself.
In this embodiment, the vacuum station is used as a frame for the milking machine. Depending on the type of mobile milking unit (for 1 or 2 cows), an appropriate pump is installed. Replacement graphite pump plates are designated PM3 GRAPHITE or PM4 GRAPHITE.
Oil installations with a capacity from 250 to 3000 liters per minute. The most common and often found on farms with milking parlors or linear milking units. They are also used to provide uninterrupted vacuum to milking machines through vacuum lines. Here the calculation for the vacuum station you require is as follows: 200 liters per milking machine. You count and order what you need. The pump is considered reliable, but requires careful attention in terms of replenishing lubricant. The pump also has Kevlar plates on the rotor of the vacuum pump. They are marked PM16 KEVLAR, PM20 KEVLAR and PM30 KEVLAR. The electric motor is eternal.
Cam oil-free vacuum stations. This is considered the most powerful and reliable. Such stations are produced with operating data from 2100 liters per hour to 4300 liters per minute.
Sometimes the vacuum gauge needs to be replaced. Well, in general, it lasts a long time, and will last a cow for a century.
Now the cost for plate vacuum units:
| Name and volume of the vacuum receiver, l | Pump type | Productivity, l/min | Power, kWt | Power, V | Cost RUB including VAT |
| PVU 20, 15 l. (vacuum installation for mobile milking machines and domestic home milking machines) | vane-rotor | 190 | 0,6 | 220 | 35000,00 |
| PVU 45, 50 l. | vane-rotor | 450 | 1,1 | 380 | 77000,00 |
| PVU 95, 100 l. | vane-rotor | 950 | 2.2 | 380 | 114000.00 |
| PVU 160, 100 l. | vane-rotor | 1600 | 3.0 | 380 | 134000.00 |
| PVU 200, 100 l. | vane-rotor | 2000 | 4,0 | 380 | 142000,00 |
| PVU 300, 100 l. | vane-rotor | 3000 | 7,5 | 380 | 161000,00 |
Popularity Agriculture among the population is growing again, and keeping livestock is considered the norm for many residents of the private sector. At the same time, it becomes easier to buy homemade fresh milk, thanks to the keeping of cows on private farms. For small properties with one or two cows the best option To obtain maximum profit is manual milking of livestock. If the number of livestock increases, additional assistance will be required. To do this, you can hire workers who will milk several cows for a fee, or purchase a milking machine. Milking machines pay for themselves quickly enough and soon become completely profitable, unlike workers who will always need payment.
Types of devices
Today, milking installations may differ:
- appearance;
- power;
- design feature and so on.
Taking into account all the distinctive features of each device, it can be determined that they are all united by the principle of operation. Each individual installation is equipped with low pressure. Also, all of them have the ability to be attached to using rubber suction cups or special clamps. The latter option is easier to operate and does not cause absolutely any problems for any farmer. As a rule, the entire milking time takes a few minutes, and does not require any labor from a person. The milk is expressed into a special container, after which it can be used for further processing or sale.
Division by technical characteristics
All types of milking machines can be divided according to the following criteria:
- by type of milk container;
- by the number of cows served in parallel;
- by type of pump;
- by the number of cycles.
In order to do right choice in favor of the milking machine necessary for specific case, each point should be examined in more detail.
By type of milk container
In fact, in any case, the milk always ends up in a container prepared for this purpose. The only difference is how big this container is and whether it is part of the milking machine itself. The most commonly used units are those with built-in cans, which are ideal for milking small livestock. For large farms, there are milking plants that collect milk from several cows at once through pipes into one large container. The container itself may be located in an adjacent room, and the number of cows served at the same time is the next characteristic.
By the number of cows served in parallel
Here the previous point should be taken into account first, since milking machines for private small herds are not capable of serving several cows at the same time. They are designed to work with only one drill or, at best, two. Large machines for farms are capable of milking several dozen cows at the same time. Of course, the cost of such a device will be appropriate, but when working with large volumes, you will be able to save on other things and much more, so the benefit is obvious.
By pump type
This classification divides all milking installations for cows into three types. Pumps can be:
- rotary;
- piston;
- membrane.
The last option is the most popular, since its price is the lowest compared to pumps of other types of action, and such a device can operate simultaneously only with a small amount cows It turns out that milking machines, the design of which is based on, are the best budget option for individual use.
To simultaneously service a small number of cows, you will need to purchase a more powerful device with a piston pump. Of course, along with the increased power, it also has one serious drawback - the device is very noisy during operation, which can disturb the cows. Also, some consider its dimensions to be a disadvantage.
The best option for silence during milking and high installation productivity would be a machine with They are further divided into dry and oil, but in any case they will be better than other types.
By number of cycles
The power of the unit and its weight depend on their number. Three-stroke engines are, of course, more massive, but at the same time more productive, while two-stroke engines are the opposite.
Separation by operating principle
All characteristics of milking machines determine their operation based on the creation of a vacuum into which milk is drawn from the udder. In this case, the vacuum in the installation can be constant or frequently changed, due to which the compression occurs.
In the first case, milk is milked in a matter of minutes and very efficiently, without leaving a drop, and is completely safe for the cow. Devices with this principle of operation are expensive, and the vacuum in them is created using centrifugal pump or pulsator. In another version, there is essentially no vacuum, and milking is carried out due to the movements of a piston pump. It is this that creates pressure surges that ensure milk expression. Such units are noticeably cheaper, but the quality of their work is not always ideal.
Possibility of movement
Depending on its dimensions, the machine can be classified as a mobile milking machine or a stationary one. The latter are used very rarely today, since working with them is very inconvenient. Mobile devices are additionally equipped with small wheels and can be used for different farm sizes. They are easy to move around the farm and easy to use.
Real consumer reviews
From the above it follows that it simply does not make sense to purchase this installation if there are one or two cows on the farm; there are many reasons for this, and first of all, the long payback period.
To serve a larger number of livestock, the benefits of purchasing a device are obvious. First of all, the device quickly pays for itself. It also helps to obtain more free time for the farmer, which was previously spent on hand milking all the cows. Considering the speed of work, along with simplicity and practicality, it is possible to reduce the number of workers previously involved in milking. This will further reduce payment costs wages employees.
The positive qualities of milking machines include the high quality of their work, which makes it possible to obtain absolutely all the milk from a cow in a short period of time.
Of course, there are also many dissatisfied with the purchase of such a unit. First of all, many people complain about the high cost of milking machines. Besides, negative reviews may be caused by incorrect selection of equipment for a particular farm. Since there are so many varieties, in order to choose the right one, you should take into account all their features.
Of course, the purchase of a milking machine should be accompanied by preliminary consultation with a professional or at least self-study all characteristics of this type of technology. Therefore, before purchasing a unit, weigh the pros and cons. And most importantly, calculate whether purchasing the device is financially beneficial for you.
To create a vacuum during operation of the milking machine, use air installations, consisting of a vacuum pump, a vacuum tank-receiver, a vacuum regulator, a vacuum gauge, a pipeline system with fittings and an engine, which are divided into rotary, piston and ejector. In turn, rotary vacuum pumps are divided into vane, liquid ring, Roots type and others. The most widely used on farms are rotary vane vacuum units of the UVU-60/45 brand and liquid ring air pumps VVN-3, VVN-6, VVN-12.
The operating principle of ejector (jet) pumps is as follows. When a liquid (or gas) flows through a pipe that has a constriction, the pressure in the constriction is lower than in the rest of the pipe (unless the flow speed in the constriction reaches the speed of sound). This was first established by the Italian physicist G. Venturi (1746-1822), after whom a tube based on this phenomenon was named. If the pumped volume is connected to the pipe at the point of its narrowing, then the gas from it will pass into the region of low pressure and be carried away by a stream of liquid. Ejector (jet) units are mounted on the exhaust pipe of the tractor and the vacuum is created due to the high-speed flow of exhaust gases.
A rotary vane vacuum unit of the UVU type includes (Fig. 2.2) an electric motor 1, a vacuum cylinder 3, a vacuum regulator 4, a vacuum gauge 6, a vacuum line 5, a vacuum pump 2. In case of frequent power outages, it can be equipped with a backup motor 7 internal combustion. The UVU-60/45 unified pump operates at a vacuum of 53 kPa with an air capacity of 60 and 40 m 3 /h.
To obtain the required flow rate, the rotor rotation speed is changed by placing pulleys of different diameters on the electric motor shaft.
Rice. 2.2 General view of the vacuum installation UVU 60/45
The rotary vane vacuum pump is designed for operation in areas with a temperate climate in the open air in the range from minus 10 to plus 40 0C and an altitude above sea level of no more than 1000 m, available in four versions.
Inside the cast-iron cylindrical body 22 (Fig. 2.3) with a ribbed surface for better thermal insulation, a rotor 17 rotates. The rotor has four grooves in which textolite blades 16 move freely. The rotor rotates in ball bearings 14 installed in the mounting holes of the covers 12 and 19, located eccentrically relative to the axis of the body. The bearings on the side of the internal cavity of the pump are closed with washers 15. To orient the covers relative to the housing when assembling the pump, pins 5 are installed. The direction of rotation of the rotor is indicated by an arrow on the pump housing. Depending on the design, the pump has one or two rotor outlet ends.
In the middle part of the cylindrical body there are exhaust ports that connect to the exhaust pipe of the frame. A muffler is installed at the end of the exhaust pipe, the body of which is filled with glass wool to retain spent lubricant.
The technological process of the vacuum installation occurs as follows. When the rotor 17 (Fig. 2.3) rotates, the blades 16, under the action of centrifugal forces, are pressed against the housing 22 and form closed spaces limited by the rotor 17, the housing 22 and the end walls 12 and 21, the volume of which first increases per revolution, creating a vacuum between blades on the suction side and then decreases. In this case, the air is compressed and forced into the atmosphere through the outlet.
The oiler consists of two main components: glass 5 (Fig. 2.4) with a capacity of 0.6 l and cup 2. Oil is poured into the glass, which is closed with a lid 7 and fixed on the cup with an arc 6. Oil flows from the glass into the cup until until its level reaches the top of the wedge-shaped cutout of the cap tube. The oil level in the cup of the oiler, version UVD.10.020, is not adjustable. The oil level in the cup of the UVA 12.000 oiler depends on the length of the protruding end of the tube and should be within 13.18 mm. When the oil level drops, air enters the glass through a cutout in the tube and the oil flows out until it reaches the set level.
The lubrication process occurs as follows. From the cup, oil flows through wicks 3 into the oil-conducting channels and, under the influence of the pressure difference in the oiler and pump, through hoses 9, holes in covers 12, 21 (Fig. 2.3) of the pump, enters ball bearings 14, through the channels of washers 15 into the grooves of the rotor 17, lubricating surfaces of blades 16, housing and pump covers. Next, the oil is discharged by a stream of air through the outlet of the pump.
The oiler ensures the supply of oil to the pump with a flow rate of 0.25-0.4 g/m 3 of air, which corresponds to the flow of oil from the glass when the unit is operating by one division on average for 1.5 hours of operation of a vacuum unit with a capacity of 0.75 m 3 /min , and on average in 1.1 hours for a vacuum installation with a capacity of 1 m 3 /min.
The flow of oil into the bearings is monitored visually through plastic hoses, and the total flow rate is monitored by divisions on the glass.
Rice. 2.3 Vacuum pump:
1.20 - bolts; 2, 15 - washers; 3 - retaining ring; 4 - pulley; 5 - pin; 6 - key; 7 - screw; 8, 22 - covers; 9 - plug; 10,11 - gaskets; 12 - right cover; 13 - cuff; 14 - ball bearing; 16 - blade; 17 - rotor; 18 - body; 19 - left cover; 21 - bushing; 22 - body
Ensuring the required oil consumption during operation is done by periodically cleaning the oil-conducting channels in cup 2 (Fig. 2.4) and plugs 4, washing the wicks in diesel fuel or changing the number of threads in the wick, and for the UVA 12.000 oiler, also changing the length of the protruding part of the tube.
To eliminate possible reverse rotation of the rotor and breakage of the blades when the electric motor is turned off, the pump inlet is connected to the vacuum line through a safety valve.
Rice. 2.4 Oiler UVD.10.020:
1 - bracket; 2 - cup; 3 - wick; 4 - plug; 5 - glass; 6 - arc; 7 - cover; 8 - gasket; 9 - hose
Rice. 2.5 Vacuum regulator
Vacuum bottle 3 (Fig. 2.2) smoothes out the vacuum pulsation that inevitably occurs during pump operation, collects moisture and milk trapped in the vacuum line, and is also used as a drain container when flushing pipelines. When the pump is running, the lid of the vacuum cylinder must be tightly closed.
Vacuum regulator 4 (Fig. 2.2) maintains a stable vacuum in the vacuum line. It consists of valve 1 (Fig. 2.5), spring 3, set of weights 4, damping plates 5 and indicator 2.
The vacuum regulator works as follows. The force acting on valve 1 from below due to the difference between atmospheric and vacuum pressure in the vacuum line lifts the valve upward, overcoming the weight of load 4. As a result, atmospheric air begins to flow through indicator 2 into the vacuum line. The amount of vacuum at which valve 1 rises is set by the weight of load 4. The amount of air flow through the vacuum regulator is controlled by the readings of indicator 2. When normal flow indicator arrow 2 should be in the middle position. To soften the vibration of the load 4, they are suspended on a spring 3, and the damping plates 5 are located in a layer of oil at the bottom.
Water ring machines of the VVN type are designed to create a vacuum in closed devices and systems. Manufactured in two versions: ВВН1 - with a nominal suction pressure of 0.04 MPa; ВВН2 - with a nominal suction pressure of 0.02 MPa.
VVN type machines are liquid-ring machines with direct drive from an electric motor through an elastic coupling.
The water ring installation VVN-12 consists of a water ring machine 4 (Fig. 2.6), driven by an electric motor 1 through a coupling 2. All this is placed on foundation slab 3.
The water ring machine consists of a cylinder body 2 (Fig. 2.7), closed at the ends with caps. In the cylinder there is an eccentrically located impeller 1, mounted on a shaft. The shaft exit from the faces is sealed with soft-packed oil seals. The water supplied to the machine feeds the water ring 7 and creates a hydraulic seal in the seals. The shaft rotates in bearings located in housings attached to the heads.
Before putting it into operation, through the suction pipe 5, the machine is filled approximately to the shaft axis with water. When starting, the liquid is thrown away from the rotor hub to the housing by centrifugal force. In this case, a liquid ring and a crescent-shaped space are formed, which is the working cavity. The working cavity is divided into separate cells, limited by the blades, wheel hub, blades and the inner surface of the liquid ring. When the wheel rotates, the volume of the cells increases (clockwise rotation in Fig. 2.7) and gas is sucked through the suction window 6. Then the volume of the cells decreases, the gas is compressed and pushed out through the discharge window 3. Water is released through the discharge pipe 4 along with the gas. To separate water from gases and collect it directly on the discharge pipe, a water separator with an open overflow pipe is installed in vacuum pumps. To separate water from gas in vacuum pumps VVN-12, a direct-flow separator 5 is used (Fig. 2.6). The direct-flow separator is a non-separable vessel with a volume of about 24 liters with a multi-blade grid built inside, through which the gas-liquid mixture discharged from the pump is separated. It ensures almost complete separation of water from gas under all possible operating conditions.
When using the machine as a compressor, a water drain is connected to the drain pipe of the separator, ensuring water drainage without gas leakage.
The advantage of water ring vacuum machines over vane vacuum pumps is that when rotating, the rotor does not touch the stator walls. However, when the rotor rotates, the temperature of the water in the pump stator increases, which reduces its flow. To increase the stability of the VVN pump, a special water cooler is installed.
Rice. 2.6 General view of the vacuum pump VVN-12
Rice. 2.7 Diagram of a water ring machine
The main parameters of the applicability of water ring machines are presented in Table 2.1.
| 2.1. Indicators of water ring vacuum machines | ||||
| Index | Standard size | |||
| VVN-3 | VVN-6 | VVN-12 | VVN-25 | |
| Productivity at nominal suction pressure, m 3 /min | 3 (2,7) |
6(5,4) |
12 (10,8) |
25 (22,5) |
| Nominal vacuum pressure versus barometric pressure, % |
60 (80) |
|||
| Maximum vacuum from barometric pressure, % |
90 |
96 |
||
| Specific water consumption at nominal mode, dm 3 /s |
0,13 (0,2) |
0,3 (0,47) |
0,5 (0,75) |
1,0 (1,5) |
| power, kWt | 13 |
22 |
30 |
75 |
| Weight, kg |
125 |
215 |
455 |
980 |
| Note: values in parentheses are for vacuum pumps version 2 | ||||
Rice. 2.8 General view of the water ring vacuum unit UVV-F-60D:
1 - vacuum line; 2 - fuse; 3 - pump; 4 - water container; 5 - electric motor; 6 - exhaust pipe; 7 - discharge pipe
The water ring vacuum unit UVV-F-60D is designed to create a vacuum and is used to complete milking machines of all types. The unit is not intended for pumping out aggressive gases and vapors.
It consists of a liquid ring vacuum pump 3 (Fig. 2.8) driven by an electric motor 5 (power 6 kW), installed above a water tank 4. The vacuum pump is connected to the vacuum line 1 through fuse 2. Residual air along with water is discharged from the room through pipeline 6 .
Basic specifications water ring vacuum unit UVV-F-60D are presented in table. 2.2.
| 2.2 Main technical characteristics of the UVV-F-60D installation | |
| Parameter name and unit of measurement | Parameter value |
| Productivity at h=50kPa, m 3 /h |
60±6 |
| Power consumed at rated mode, kW | 4±0.4 |
| Ultimate residual pressure, kPa |
15±5 |
| Overall dimensions, m |
0.65x0.36x0.75 |
| Weight without water, kg |
110 |
| Volume of liquid poured into the water separator, dm 3 |
50 |
| Nominal diameter of the pipe, mm |
40 |
Some processes require very high pumping speeds, even if not at very high speeds. low pressures. These requirements are met by two-rotor positive displacement pumps such as Roots blowers. The diagram of such a pump is shown in Fig. 2.9.
Rice. 2.9 Diagram of a Roots-type double-rotor pump
Two long rotors with a cross-section resembling a figure eight rotate in opposite directions without touching each other or the housing walls, so that the pump can operate without lubrication. There is also no need for an oil seal, since the gaps between the fitted structural parts are very small.
The rotor rotates at a frequency of up to 50 s -1, and high pumping speed is maintained up to pressures of the order of one millionth of atmospheric pressure. Each rotor may have two or three cams.
Although such pumps are capable of operating with direct exhaust to the atmosphere, they are usually equipped with an auxiliary rotary oil pump at their outlet, which not only lowers their ultimate pressure, but also increases efficiency by reducing power consumption, allowing for less cost. complex system cooling. The auxiliary pump, which passes the same mass of gas but at higher pressures, can be relatively small.
