Pump test bench PM universal

for the automatic testing of the control behavior of Personal Air Samplers (PAS) for the sampling of hazardous substances in the air at the workplace.

 Fields of application

The control of the air volume flow of the PAS and an automatic switch-off if the initially set flow rate can no longer be kept constant within the required tolerances is particularly important for the correct sampling of hazardous substances on the person. The pump test bench PM universal is used to check pumps operating with a volume flow between 33 mL/min. and 10 L/min. Typically, this is used to collect airborne particles on a filter. The pumps must readjust the volume flow as the filter material gradually fills up and resistance increases. The PM universal tests this control behavior by simulating a filter clogging.

 How it works

The PM universal pump test bench is equipped with a programmable logic controller (PLC). It is operated via a menu-driven key display. The pump to be tested, an external pressure sensor and volume flow meter are connected to the measuring stand. The simulation of a filter clogging is carried out either stepwise or continuously via three different ramp programs. From the records of the connected measuring instruments it can be read up to which differential pressure the pump to be tested can maintain its nominal volume flow. With an additional rechargeable battery test program, the running time of a battery can be tested at an adjustable pressure difference.

Particulars

- The step program works optionally with a total of 11 steps (coarse step program) or 21 steps (fine step program). Each individual stage lasts two minutes and corresponds to a pressure difference of 22 or 11 mbar. A maximum pressure difference of 220 mbar from the current room pressure can be set. On request, the device can be adapted to other pressure differences.

- Three different ramp programs are available to the user. Each program starts at a differential pressure of 22 mbar and ends at 220 mbar. The first program runs for 30 minutes, the second for 2.5 hours and the third for 5 hours.

- A special feature of the PM universal is that a pressure stage is "frozen" after a certain settling time. The state of the stopped regulator setting then functions like a nozzle with a fixed value. Any fluctuations in pressure and related volume flow are now caused exclusively by the pump and can be evaluated better than two mutually influencing control loops by the pump and internal controller. In addition, an undesired long-term drift of a pump can be proven. If necessary, the user can deactivate "freezing".

- If the deviation between setpoint and actual values of the pressure difference is too high, e.g. after a pump switch-off, an automatic switch-off of the program and a trigger signal are started (potential-free relay contact).

- The user can activate an additional pump run time for warm-up, which can be set between two and 30 minutes.

- Optionally, the PM universal can be equipped or retrofitted with an electric ball valve to test the automatic shutdown of a pump if it has not yet shut down at a differential pressure of 220 mbar.

Technical data

Dimensions (W x H x D): 60 x 31 x 31 cm (19'' x 6 HE)

Weight: approx. 9 kg

Electrical connection: 230 VAC, 50 Hz

Power consumption: max. 60 VA

Designed for volume flows between: 33 mL/min. and 10 L/min.