A pump for transferring precise amounts of fluid from a container to a patient. A pump apparatus has a defined volume pump chamber divided by a diaphragm into a pumping fluid portion and a pumped fluid portion. The pumped fluid portion receives and exhausts pumped fluid in response to a decrease or increase...http://www.google.com.au/patents/US4265600?utm_source=gb-gplus-sharePatent US4265600 - Pump apparatus
