The Smart Pump Module Webinar

Q&A Session

What kind of pressure sensor is the module using and what is its operating range? Can you provide any idea of the power consumption of the module (separate to the pump)?

The pressure sensor is a digital sensor. The sensing function is comprised of two separate sensors - a barometric sensor to measure the atmospheric pressure, and an absolute sensor. The combination of those two sensors provides gauge pressure. The operating range is 0 to 1.7 Bar absolute (note that this is reported as gauge pressure). The quiescent power consumption of the module is around 40-60 mW, depending on the supply voltage.

Do you have any Disc Pump products for high pressure like 4 Bar?

Not yet, but we are currently working towards a 1 Bar Disc Pump. You can combine multiple pumps together to deliver higher pressure, however, although elevated pressure may cause pumps to fail, and so we would recommend not running above 1 Bar for extended periods or at elevated temperature.

The highest pressure Disc Pump we have currently is the HP Series Pump at 600 mbar.

The digital interface provides control, but does it also provide the output from the on-board pressure sensor?

Yes - there is a set of registers that provides access to the control and operating parameters of the Smart Pump Module, such as the drive power the pump is consuming, and the pressure reading.

What is the connector called that is used?

It's from the Molex Picoblade, part 53261-0571. You can find mating cable assemblies here: bit.ly/3mtVPh0.

Can you overdrive the module to 1.4 W for intermittent duty, similar to the app?

Yes - all pumps are rated to 1W for continuous use. XP Series pumps are rated up to 1.4W for intermittent use, so you can overdrive the pump in short bursts for extra performance.

Is the pump fluid compatible - water, oil, ink ?

Not directly - the operating mechanism of the pump is to setup a standing pressure wave in an acoustic cavity which requires a compressable medium - which liquid is not. However, many of our customers use the pump to move liquids via air-over-liquid or pressure-driven flow. For many this can be an advantage, for example, in diagnostic systems, where you don't want the sample to come into contact with the pump as there may be issues with contamination. Using a buffer of air to move liquid around addresses that problem.

Please see our blog post on 3 Fluidic Control Methods with Disc Pump.

Can you cover the compatability of fluid to go through the pump or supply materials so we can?

Yes, we can provide a list of wetted materials that gases pass over upon request.

Is the Smart pump circuit and PCB an Automotive certified?

No - is isn't. If you need a certifiable design for a particular application, we recommend you start with the reference designs for our standard drive circuit, and apply the constraints imposed by the relevant standards.

Are the peak flows shown in the chart from 1 W?

For the XP Series curves, the peak performance shown is for 1.4 W intermittent drive.

Is it possible to manage a vaccum of -14 mBar?

Yes. The pump can deliver very stable vacuum levels across a wide range, from the maximum vacuum for the particular Disc Pump product on the module, all the way up to atmostpheric pressure. Unlike conventional motor-driven pumps, Disc Pump has no stall speed, so it can run at very low 'speeds'.

Some customers in the printing inkjet space will be using even lower pressures, -10 to -5 mBar vacuum for example, to control a constant level of vacuum in their printheads to maximise print quality. You can read more on maintaining meiscus pressure in inkjet printers here.

How fast can you control the output pressure?

The pump itself responds in a matter of milliseconds, and in principle the output pressure at the exhaust port of the pump could respond similarly. However, using the output of the pump in a system with an internal volume and flow resistance will dictate the time constant with which you can change pressure in your system. The lower the flow resistance and the smaller the internal volume, the faster you will be able to change pressure in your system.

To note - the pressure does not bleed quickly back through the pump. For example, if you run the pump up to a high pressure level and reduce the power, the check valves in the pump will seal so that pressure build up will be retained in the system, and will only quickly reduce if there is another outlet somewhere. For customers that need to be able to raise and reduce pressure very quickly, the best option is to use a solenoid valve or a fixed orifice as a bleed to allow the pressure to dissapate quickly.

Is there a development kit, and if so how much does it cost?

All of the pump modules are priced differently depending on the pumps chosen; therefore pleaes contact us and we can take you through the pricing for different variants.

Do I need a filter?

We recommend the use of a filter with a pore size of 3μm or less in order to prevent the ingress of particulates that might otherwise limit the lifetime of the pump.

Do I need vibration isolation when mounting the SPM?

We recommend you use nylon bolts and washers (or stand-offs) to prevent any high-frequency vibration transmission, which might otherwise cause audible noise.