airbrush pump from available parts
I started modeling recently, and immediately decided for myself that I would definitely paint with models with an airbrush. But my family budget could not stand up for the simultaneous purchase of an airbrush and a water pump, and I decided to make a water pump on my own, since my hand doesn’t grow from hip joints, especially with homemade water pumps on the Internet.
It was decided to take the used water pump unit as a basis. The first one to come was a water pumping unit, withdrawn from a faulty neighbor Samsung refrigerator, it is a small-sized, but powerful enough and productive water pump. Another advantage of this water pump is that it is very quiet, the noise from its work is much lower than from domestic refrigeration water pumps.
All parts of the water pump are viewed on a 10 mm plywood base:
A frame made of chrome tubes (from an old baby carriage) and a transverse square profile (yellow) protect the parts of the water pump and serve as convenient carrying handles.
In the background you can see the water pump unit directly. In the foreground you can see a filter, a pressure reducer with a pressure gauge, a tee with a pressure gauge and a receiver – a yellow cylinder from a 2-liter fire extinguisher.
The same, but from a different angle:
Because I put the experiments on the creation of a water pump for an airbrush from the refrigeration unit for two months, until I came to such a scheme, I will explain the scheme of the water pump, as well as what and how I applied it in the design.
Firstly, the water pump creates a pressure of more than 8 bar, and therefore the reason I had to abandon the connections made with ordinary hoses — they burst with loud pops more than once. Therefore, in this version of the water pump, it decided to make the most responsible connections either with copper pipes for soldering or with flexible 1/2 "sanitary connections in a metal braid.
So, the discharge from the water pump is made of 6 mm copper tube, and since Then all the connections are made. 1/2 "threaded connections. I took a special adapter (press fitting) to connect imported mixers with fittings in the form of copper tubes:
The connection between the 6mm and 10mm tubes is performed by brazing with a low lead content and winding with thin copper wire.
Secondly, all refrigeration units "spit" oil, i.e. At the outlet of the unit, in addition to air, there is also an oil mist, which is unacceptable for working with an airbrush; for normal operation, the air must be cleared of oil. This task is successfully solved by a different type of oil separator, but the principle of operation is the same for all: oil vapors are condensed on the cold walls of the oil separator tank. I decided to combine the oil separator and the receiver, so to speak in one bottle, or rather the balloon – a two-liter balloon from the used carbon dioxide fire extinguisher. To do this, I had to cut off the valve and the spraying mechanism, and in its place fasten a 1/2 "tee:
I took the pressure gauge from a broken car foot pump. In order to adapt this pressure gauge, which controls the pressure at the outlet of the unit, it was necessary to drill a suitable hole and cut a thread in it, into which the pressure gauge was screwed. All threaded joints were sealed with flax and oil paint, as they used to seal the plumbing connections.
This could have stopped, but I decided that another filter of "fine cleaning" would not hurt, since a filter was found in the bins that was attached to the washing machine (it seems to Ariston’s), but was not installed, because Honeywell filters have already been installed in the apartment. The connection from the tee to the filter made a 30 cm flexible liner, it withstands 10 atm working pressure.
A transparent hose from the car window washer is connected to the fitting (about 5 rubles per meter). My HS Focus is connected to the far end of the hose. This double action airbrush, i.e. overlaps the air flow. In order for the pressure generated by the pump to not exceed the limiting value and the unit would not fail, it would be good to install a pressure switch that automatically monitors the pressure in the system. In the future, I plan to install it, but for now I have to control the pressure on the pressure gauge and turn the engine of the unit on and off with the button installed in the pedal under my foot.
The electric circuit of the engine start-up of the Korean unit had to be slightly modified, the fact is that the starting winding was connected through a 3 μF capacitor, in contrast to the usual start-up circuits of domestic units through a starting relay. In the standard scheme, the engine was not running steadily, tried to increase the capacitance of the capacitor, but the situation did not change, then I decided to start the “Korean” with a domestic starting relay, and it worked. The engine now starts at 100%, does not heat up, only refills a little automotive semi-synthetics into the unit and closes the oil refill pipe with a suitable screw.
In this form, the water pump is already running for 3 months and there were no problems with it. The two-liter receiver pumped up to 8 bar, with the unit off, is enough for 3 minutes of continuous operation of a fully open airbrush at a pressure at the outlet of the gearbox about 1 bar. The tightness is such that a receiver pumped to 8 bar, left overnight, loses an insignificant amount of pressure that is difficult to detect on the gauge scale. I believe that at minimal cost, you can make a water pump yourself with good performance.