The diaphragm pump is the beating heart of boom sprayers and atomizers whose performance depends on the pump’s good operation.
One aspect not to be underestimated when it comes to maintenance is to regularly check and change the oil and use the most suitable one: a perfect lubrication helps the optimal operation of the pump components and increases its performance.
For this reason, Comet has created the NEW COMET C1 ADDITIVATED MINERAL OIL - available in 1 liter and 5 liter versions - which preserves the components in the best possible way, ensuring maximum performance and great reliability in all working conditions.
DIAPHRAGM PUMP MAINTENANCE AND OIL
The mechanical parts contained inside the pump casing are preserved from wear and seizures thanks to the lubricating oil which forms a protective cushion through the ports on the liners exposed by the plunger cycle. This cushion has a variable volume depending on the pressure and vacuum of the pumping chamber and can become inefficient if residual air is present.
When replacing diaphragms it is therefore necessary to eliminate as much air as possible between the plungers and diaphragms. This is accomplished by removing the oil tank cap and directing the ports on the liners in a vertical position, to facilitate air escape.
Before reintroducing oil, it is always better to weigh it in a jug to be sure to have the quantity indicated in the diaphragm pump manual. While the oil is being poured in, by letting the shaft rotate manually and tilting the pump several times, you will see air bubbles coming out of the tank until, after having reached the correct level (between the minimum and maximum indicators), the bubbles stop coming out, so you will know that you have correctly purged the air.
For some pumps, especially the larger ones, you can run the system at low revs and without pressure for a few minutes, leaving the tank open: it may happen that the oil level drops due to the last air bubbles escaping. At that point you will only need to top up a little and then go back to work at full speed.
PROBLEMS WITH OIL: TROUBLESHOOTING
Other critical oil-related issues that a diaphragm pump may have are, e.g., problems with priming, pressure, pulsation, noise or excessive oil consumption.
Excessive noise from the pump can mean that there are obstructions in the intake line and in the filter that may cause the oil level to drop: simply inspect the intake line and remove the obstructions to restore proper operation.
Excessive oil consumption, on the other hand, may be related to cuts or tears in the diaphragms that cause liquids or fluids to come into contact with oil. In such a case, the damaged diaphragms must be identified and replaced, as well as the oil replaced to prevent contaminated oil from damaging the entire pump.
ROUTINE MAINTENANCE OF THE DIAPHRAGM PUMP
The proper maintenance of the diaphragm pump can be split into three main steps: before, during and after use.
BEFORE USE
Before use, inspect the pump and make sure that:
- the intake and delivery circuits do not show signs of wear, bottlenecks and blockages
- all connections (fittings, ring nuts, hose barbs) are properly tightened
- the pump is securely attached to the frame
DURING USE
Always check the oil level and color: if the oil level drops suddenly or its color suddenly darkens, stop working.
When the pump is new, the oil inside is generally light yellow and clear, but already after a few hours of work it begins to darken and become cloudy due to the rubbing of the plungers in the cylinders and of the other components, and the micro metal particles that this rubbing releases.
Together with the level indicators, coloration is one of the main signals to be kept under control to know the state of the oil, evaluating it according to the working conditions of the diaphragm pump (high temperatures, low temperatures, work intensity, etc.).
If the oil turns a gradually darker yellow, these are standard conditions, while if it suddenly becomes darker it means that the pump has been working under severe conditions. The alarm bell goes off when oil in the tank becomes gray or milky: this means that one or more diaphragms are torn or punctured and the lubricating oil has been contaminated by the aqueous solution; in this case, stop operation immediately to prevent the emulsion formed from causing even serious damage. At this point, more extensive maintenance should be carried out, either on your own or by contacting a service center.
AFTER USE
Run clean water through the pump to clean it of chemical residues.
In cold weather areas, run a mixture of water and anti-freeze fluid and drain the manifolds before storing the pump for winter.
After every 300 hours or at the end of the season (depending on which event occurs first):
- install a new series of diaphragms
- inspect valves and replace oil
- always drain and flush the pump with clean water before servicing or disassembling it
COMET MAINTENANCE KIT
In order to facilitate the routine maintenance of your pump, Comet has designed a MAINTENANCE KIT that comprises a set of original spare parts consisting of
- DIAPHRAGMS
This is the most important element of the pump, available in NBR, Desmopan and Viton. - VALVES
Intake and delivery valves. - GASKETS and SEALS
O-rings to create a watertight seal between the valve and the head.
REQUEST THE COMET MAINTENANCE KIT FROM YOUR TRUSTED DEALER
Remember: it is essential to perfectly check and maintain the pump’s diaphragms, so that the pumping chamber remains well separated from the transmission and the fluid to be pumped does not come into contact with the mechanical parts and oil.
These small maintenance jobs can significantly extend the life of your diaphragm pump, avoid damage and breakage and increase its performance.
