How make a piston pump pulse water and be able to adjust the water speed?

Hi



I need to pulse water at 1200 pulses a min (that's 2 a sec). I would do this using a piston pump attached to an offset gear and a motor. The max amount of water i would need in one pulse is 1.5ml.

The water would then be pulsed up through a tube and out of a 1mm diameter hole.



However i want to be able to adjust how fast the water comes out of the hole. I cant adjust the 1mm hole. And because i need 1200 pulses a min i cant adjust the frequency of the pump to change the water speed.



Does anyone have any ideas how to go about doing this?



Would i need to use a flow regulator or a pressure regulator and if so where would it go?



Any ideas would be great! Many Thanks.How make a piston pump pulse water and be able to adjust the water speed?This sound a lot like fuel injection. It seems to me that you want to vary the stroke of the piston, which varies the volume and the velocity, as the diameter is fixed. However I think the approach below is easier to design and control.



Think about the fuel injection for cars. Here the fluid is constant pressure, and a valve is operated by a solenoid for a given time of a few milliseconds. Generally though, the time is varied, which varies the volume, but not the pressure. The common rail is actually an accumulator which can have the pressure adjusted, so it is constant but adjustable pressure to give the 1.5ml volume through the 1mm orifice. The solenoid valve releases a known quantity by the open timing, the 1mm diameter controlling the flow. Note that the %26quot;high%26quot; pressure pump maintains the pressure in the accumulator common rail, and the regulator for the rail can return unused fuel to the tank. The valve is driven by a timer that has a variable pulse width to measure the volume. A special electrical driver device is needed for the valve. The timer can be triggered at regular intervals, or by some event like the cylinder position in a car is used. The accumulator pressure and its pressure pump are separate issues. It seems the pressure is calculated for something like 3 pulses a second of up to 1.5ml through a 1mm diameter orifice. This will be a relatively low pressure (compared to a car or diesel system), but best for you to determine that pressure yourself.



The tubing to the orifice will be elastic, and smooth out the flow, so if you need sharply defined pulses of fluid the valve is close to the orifice.



It seems to me that some components of a car or diesel common rail system could help in providing the complex parts cheaply. These would be adapted to your needs. The link below explains some more detail.



An alternative to this is to use a common rail system, but devise a mechanically operated valve to release the pulses through the orifice.