Review and Discussion Problem 6.4

a) Find three examples of elegant inventions or designs in your home, office, or plant and study them to determine why they are superior. These will probably not be complex devicesw, but more likely simnple ones, such as airtight food containers that are easily opened and closed.

b) Now find three examples of devices in which you see deficiencies. What could be done to eliminate each of these deficiencies?

Practice Project 6.5

Infusion of fluids into the human body is part of the treatment for various diseases or deficiencies. The infusion process is generally quite long, ranging up to several hours duration, and the infusion rate is very important and must be controllable. The source of the fluid is a plastic bag or bottle; the fluid flows through disposable and deformable plastic tubing, reaching a vein of the patient through a needle. To control the rate, a pump is usually used that can be set to deliver a fixed number of cubic centimeters per hour. The delivery system must be closed; that is, the pump mechanism must be made so that it is not possible for fluid contamination to occur. Devise one or two methods for effecting the pumping action.

Hint: Some ideas are 1) gravity, 2) centrifugal pump, 3) peristaltic pump. What other ways are there to pump liquid or to control its flow?