A milking robot's compressor must be installed in a closed room, separate from the cow shed, ventilated, frost-free and protected from dust. The air it draws in must come from a clean, ammonia-free area. A 7.5 kW screw compressor such as the K 75 gives off most of the energy it consumes as heat, so it needs a fresh air inlet low down and a hot air outlet high up, both sized for that heat.
Choosing the model by the number of robots is covered on our page on the compressor for dairy farms and milking robots. Here we talk about where to put it.
Why does the room matter more than in a workshop?
In a workshop, a compressor runs a few hours a day. For a milking robot, it runs day and night, all year round. Whatever it draws in, it draws in continuously. And a dairy farm combines four enemies of the compressor:
- Dust from forage, straw, feed and bedding. It clogs the intake filter and fouls the cooler.
- Ammonia given off by manure. It attacks copper, found in heat exchangers and wiring, and electrical contacts.
- Heat in summer, when the room sits under a steel sheet roof or next to the milk tank and its refrigeration unit.
- Frost in winter, in an open or poorly insulated building: condensate freezes in the receiver, the drain or the dryer.
Where should the room be?
The good locations, in order of preference:
- A dedicated plant room, next to the dairy or the robot room, with a door that closes and an air intake on the outside, away from the animal buildings.
- The dairy itself, if it is large enough and the noise bothers no one. The K 75 is rated at 66 ± 2 dB(A). Watch out for the heat from the tank's refrigeration unit.
- A room in the machinery shed, provided it is closed and forage dust cannot get in.
Avoid the cow shed, the collecting yard, the muck heap, the feed store, and anywhere near the slurry pit for the air intake.
How much ventilation is needed?
A compressor turns most of the energy it consumes into heat. That heat has to leave the room, otherwise the temperature rises, the compressor trips, and milking stops on a heatwave day.
The step-by-step calculation, as a guide:
- Compressor power: 7.5 kW for a K 75.
- Heat to remove: around the power consumed, so about 7.5 kW when the compressor runs at full speed.
- Accepted temperature rise in the room: for example 10 °C above outside.
- One m³ of air warming by 10 °C carries away about 3.3 Wh. For 7,500 W, you need about 7,500 ÷ 3.3 ≈ 2,300 m³/h of fresh air.
For an 11 kW K 110, that comes to about 3,300 m³/h. These figures justify a low inlet grille and a hot air outlet duct, or even an extractor fan controlled by a thermostat. The compressor's data sheet gives the cooling air flow to plan for. Our article on the compressor room sets out the general rules, and our guide on temperature and altitude explains the effect of heat.
How do you protect the compressor from dust and ammonia?
- A clean air intake. Bring the fresh air in from outside, on the side away from the animal buildings and the muck heap, sheltered from the rain.
- An inlet grille with a pre-filter, cleaned regularly. A clogged pre-filter reduces ventilation and heats the room.
- A closed door, especially during bedding up, feeding out or mucking out.
- Checking the air filter more often than in a workshop. In a dusty environment, the service may fall due earlier than planned; a clogged filter shows on the controller or to the eye.
- Cleaning the cooler with a blow gun, with the compressor stopped, blowing from the inside out.
If the room cannot be isolated from ammonia fumes, talk to our technicians before installation.
How do you keep the room frost-free?
- Insulate the room, especially if it is in an open building.
- Keep the heat in winter. Dampers in the outlet duct can send the compressor's hot air back into the room in cold weather and outside in summer.
- Protect the drains and the condensate outlet, which freeze first.
- Check the operating temperature range in the manuals of the compressor and the dryer.
Recovering heat for the dairy's hot water
A dairy farm uses hot water for washing the bulk tank and the milking parlour. A compressor that runs day and night produces heat day and night. Part of it can preheat water or heat the dairy in winter. Our guide on heat recovery explains the set-ups, and our calculator gives an order of magnitude for the energy you can recover.
The connections to plan for
- Electricity: a 380 V three-phase supply with its protection, and the option of running the compressor from the generator if there is one.
- Air: an outlet valve, a non-return valve and a spare connection for a second compressor, even if it has not been bought yet. See our guide on connecting to the air network.
- Condensate: an automatic condensate drain and an oil-water separator. Condensate contains oil, so it goes neither into the slurry nor into the washing water.
- Access: enough space around the machine for servicing, and a way in to deliver or replace it.
Checklist for every visit
- The pressure gauge shows the usual pressure.
- The controller shows no alarm and no service reminder.
- The air inlet grille is clean.
- The drain has discharged the water.
- The room temperature stays reasonable.
Servicing follows the hour meter: first service at 500 hours, then every 1,500 hours, or about every 9 weeks for a compressor running continuously. The service kits group the parts for each model.
To choose the compressor that will go in this room, start with the configurator, then ask for a quote, attaching a photo or a plan of the intended location.
For your trade: Air compressor for dairy farms and milking robots.