In case of: filling hydraulic circuit or level meter cups; Otr suggests Hydraulic circuit saturator.

The instrument is composed by a cylinder where is introduced liquid, an inner flask where is pumped air to pull the liquid outside of the cylinder without mix it up, a couple of hydraulical pipe innests and its own valves used like inlets and outlets and sealing flange for securing the inner flask.

After there are, a couple of eyebolt for the belt and strap, a posterior eyebolt to hang the saturator when is almost empty and an inlets air valve.

How is it used?                                          

The saturator needs a little portable compressor to limit the pressure, limited to 0.5bar. At this point, engage the copressor to the valve and engage the 10mm pipe to the hydraulic circuit to saturate, closing the 6mm valve. During the emptying, lie down the instrument, with the valves directed to the floor and fill it up a second time with liquid if it isn’t enough.