Calibration of spraybars at Cold Chon
We carry out a calibration on the monitoring unit in each of our trucks, at least annually or following a major change or upgrade, such as a new emulsion pump being fitted to a truck. We also provide this facility free of charge to our customers and provide expert technical advice and assistance, as well as advising them on any improvements adopted in spraying techniques etc.
We have a specially designed and purpose built test bay in our site in Oranmore, from which we carry out tests on upto 75 trucks annually. The tests are calibrated to BS 1707 and EN 12272-1 and also involve a considerable number of visual checks that must be completed in order for the calibration to be completed successfully.
Truck is pre-weighed, and preferably empty prior to test. All filter pots are opened and inspected. Trucked is filled with adequate product to carry out the tests. When at the desired temp the truck is backed over the sump and product sprayed through the jets. Any blocked / damaged jets are remedied. The extendable bars are greased etc for ease of movement. Any air leaks are identified and repaired. The emulsion pump is checked and any seepage stopped by tightening packing etc.
Minimum revs on the engine to achieve the desired pressure on the bar is determined. The automatic dump valve is checked. The monitoring unit settings such as calibration factor, is checked as well as the printer and paper is replaced if necessary.
Spraybar is then backed over a special slotted test tray and normal spraying conditions simulated until the first slot is filled. Average depth of product across the transverse is then measured and recorded. Forward momentum of truck at the min engine rev is then determined. Truck is then weighed on a 'Weights and Measures' calibrated weighbridge.
The monitoring unit is set to record the spray volume, and spray conditions are again simulated for a specific known period of time. The truck is then reweighed and if the monitoring unit is within a tolerance of + 2% the truck is passed. If outside this range a calculation is performed and a new calibration factor inputted to the monitoring unit and the test is repeated (i.e. the truck is weighed on a 'Weights and Measures' calibrated weighbridge.
The monitoring unit is set to record the spray volume, and spray conditions are simulated for a specific known period of time. The truck is then reweighed). This step is repeated until the difference between the actual and the recorded (by the monitoring unit) amount is within the acceptable limits.
A very detailed spray rate chart is then generated; specific for each individual truck detailing the speed at which a series of spray rates can be achieved. A historical record is generated on a truck, if presented regularly and any trends can also be highlighted, in many cases ensuring prevention of problems rather than repairing problems after they occur. Most minor adjustments / repairs can be carried out by our own highly skilled in-house fitters on the test day ensuring that the truck passes, and eliminates the need for costly retests.