For a fruit and vegetable packhouse with a grader, a bagging machine and a pallet wrapper, a 4-in-1 screw compressor of 1.1 to 2.2 m³/min covers most cases: the K 75 for a small on-farm packhouse, the K 110 or K 150 when several lines run during the season. The flow is worked out machine by machine, and the air that touches the produce must be dry and filtered.
The packhouse is one of the air needs of a farm, covered on our page on the compressor for agriculture. Here we focus on the packing line.
Where air works on a packing line
- The grader: its pneumatic ejectors send each fruit to the right outlet according to size, colour or defects. They use the most air, and in bursts.
- Packing machines: bagging machine, punnet filler, flow wrapper, labeller. Their cylinders and valves work on every cycle.
- End of line: pallet wrapper, crate stacker, palletiser.
- Cleaning: blowing brushes, belts and sensors clean.
If your packhouse uses an optical sorter with air jets, its calculation is different: see our article on the compressor for an optical sorter.
The calculation, step by step
Step 1. Read the air consumption and working pressure on each data sheet. For the grader, the manufacturer usually gives the consumption per lane or for the whole machine, at a given throughput.
Step 2. Add up what runs at the same time during the season. Blow guns are counted at 50%.
Step 3. Add a 25% margin.
Example of a packhouse in full season (figures for guidance only, replace them with those from your data sheets):
- grader with ejectors: 450 l/min
- bagging machine: 200 l/min
- pallet wrapper and stacker: 150 l/min
- two cleaning blow guns: 2 × 150 l/min counted at 50% = 150 l/min
- total: 950 l/min, or about 1,190 l/min with the margin
The K 75 (1,100 l/min at 8 bar) would be tight. The K 110, 1.7 m³/min at 8 bar, covers this need and keeps a reserve for one more machine.
Which model for your packhouse?
| Packhouse | Recommended model |
|---|---|
| On-farm packhouse, one grader and one packing station | K 75, 1.1 m³/min at 8 bar, 420 L tank |
| Packhouse in the example, several packing machines | K 110, 1.7 m³/min at 8 bar |
| Two lines, or shift work during the season | K 150, 2.2 m³/min at 8 bar, or S 150 with a dryer |
Ejectors use air in bursts when defects arrive in series. An air receiver next to the grader holds the pressure at that moment. The air receiver size calculator gives an estimate.
Air that touches the fruit
An ejector or a blowing nozzle can touch the produce. Our compressors are lubricated: the dryer and filtration of the K series give the basis, and fine filters as close as possible to the grader protect the points where the air touches the fruit. The air class under ISO 8573-1 is set with our technicians, the line manufacturer and your quality manager. Our guide to ISO 8573-1 air quality explains how to read it.
Pitfalls specific to a packhouse
- Pipes that run through a cold store. A refrigerated dryer does not go below a few degrees. If the air passes through a room colder than its dew point, water condenses in the pipe, and can freeze below zero. Avoid that route, or fit a desiccant dryer on that branch. Our article which air dryer to choose compares the two.
- Washing water. A packhouse that washes or brushes vegetables is damp. Install the compressor in a dry room, away from splashes.
- The season and the rest of the year. The line runs hard for a few months, then hardly at all. A variable speed screw compressor follows that demand instead of running unloaded.
- Service before the season. First service at 500 hours, then every 1,500 hours, with a reminder on the controller. Do it before the first harvest, with the model's service kits.
Enter your machines in the configurator, or send us the data sheets of your line with a quote request.
For your trade: Compressor for agriculture.