Automatic paint spraying is drived not only by a bare spray gun but also piping with backend pump system. The most popular selection of paint pump includes a pressure pot, diaphragm pump, gear pump and piston pump etc. A propriate choice will greatly help with our operation and reduce potential issues. In following section we will provide quick guidance on how to select among the different paint pumps to support our production requirements.
Either diaphragm or gear pump or piston pump or even the pressure pot is widely used in painting industry, so what’s the difference for each option? Let’s describe using the most simple words and logic for quick understanding.
Diaphragm pump – Diaphragm pumps feature a flat, diaphragm inside of a housing held together by screws. When pumping, the diaphragm flexes up and down to create pressure. These pumps tend to be more durable because there is no contact with the cylinder wall.
Diaphragm paint pump is the mostly used for its stability and affordable costs. It provides a a constant flow rate over a range of differential pressure in batch processes. It’s ideal choice for spindle painting line (fixed spray gun continuous spraying)
Gear pump – In a gear pump, liquid flows into the pump from an input tube; from there, gears rotating in opposite directions suck the fluid in and send it around the container. These gears are extremely close together and are very close to the edges of the container as well, making sure no liquid can get stuck in this system or loop back around. This creates a slight vacuum where the liquid is being pushed around the container, allowing it to continue forward when it hits the open space between gears and funnels through the output tube.
Comparing to diaphragm paint pump, gear pump is advanced choice for precise fluid rate control. We can freely adjust the gear speed for required fluid rate, so it’s widely used for robotic painting system that requires precise paint control.
Piston pump – The piston pump is strong, as well as simple devices. These pumps are made with a chamber, a piston, and a couple of control devices. These pumps function by flowing downward into the chamber, thus reducing the media within a hand pump. When the air pressure surpasses from the opening valve spring, then the reduced media can be sent throughout the open exit valve. As the piston is drawn back-up, then it releases the inlet valve & shuts the outlet valve, thus suction can be used to draw in extra media for compression.
Piston pump is pressurized device and most models can reach up to 90 psi. Higher psi delivers smaller droplet size and has a further reach. Comparing to diaphragm pump, piston solution provides a simple structure which is easier for repairing. However, piston pump is incapable of handling wettable powders, abrasive or bleach solutions which can cause premature wear or failure of the pump.
Pressure pot – As its name tells, a pressure pot is a metal pot with pressure gauge and air/liquid in/out nozzles. Some advanced configuration provides a penumatic mixer for paint mixing.
Pressure pot is the simplest choice among all available options. We have an article for dedicated comparison with a regular diaphragm pump here.
For any above paint pump selection, we should consider the following when configuring our paint supply system:
- Fluid rate: If we have specific requirement on fluid rate regulation
- Paint properties: Such as the paint viscocity and solid component percentage etc
- Tank size: Especially when we use pressurized tank or pot, we must choose a suitable storage size as we don’t want to open it frequently.
- Comfort: Components such as shoulder straps, carrying handles and frame size will affect your comfort and fatigue level when using the sprayer.
- Safety Features: Look for shut-off valves, with lock-on/lock-off feature, to control spray and prevent dripping.
- Nozzles: Interchangeable nozzles allow for multiple spraying tasks.
