The following information is what we are currently using for the negative pressure system.
However, (unlike explained below) we will be using a single pump and connecting the pump to 2 different lung chambers in series.
Computer compatible drive: 07551-00 - http://www.coleparmer.com/catalog/product_view.asp?sku=0755100&pfx=EW
Computer Software: 07550-74 - http://www.coleparmer.com/catalog/product_view.asp?sku=0755074&pfx=EW
Computer Cable: 22050-54 (RS-232 to RS-232) - http://www.coleparmer.com/catalog/product_view.asp?sku=2205054&pfx=EW - or 22050-60 (USB A to USB B) - http://www.coleparmer.com/catalog/product_view.asp?sku=2205060&pfx=EW
Pump Head: 77200-62 (EZ-Load II) - http://www.coleparmer.com/catalog/product_view.asp?sku=7720062&pfx=EW
Mounting hardware f/2 heads: 77200-02 - http://www.coleparmer.com/catalog/product_view.asp?sku=7720002&pfx=EW
Tubing: Size L/S 36; material depends on fluid - http://www.coleparmer.com/catalog/product_view.asp?sku=9644036
The drive listed above will allow up to 2 pump heads to be mounted for use. One line of L/S 36 tubing running at 600rpm will give you ~2900ml/min with water; doubling up the pump head will give you ~ 5800ml/min. This will give you 800ml in about 8.3seconds.
With the software, we could daisy-chain 2 drives with 2 pump heads each and provide ~11,600ml/min flow; 800ml in about 4.2 seconds. (Technically we could connect a 3rd drive with 2 pump heads, but since the 2 drives are within the 3-6 second range for an 800ml pull, it may not be worth it.)
To do this with one pump, we would have to up the size of the drive and tubing, but once we move to the larger pumps, we would no longer be able to use a computer to program and control. We would require a PLC system with 4-20mA or 0-10V control for speed and motor direction.
Since in the end we are placing our 2 lung chambers in series we will only need one pump to provide the necessary flow rates since placing the chambers in series doubles the pumps actual use.
For more details on other pump types looked at see Pumps.