The following is a list of general information on pump types; for details on the pumps we will be using see our design section of the wiki.
There are three basic types of pumps that are relevant to us: the positive displacement, centrifugal, and jet pumps. Within each category there are several different pumps that will be discussed below. The basic concept of the positive displacement pumps is that they create some sort of cavity using pressure to pull the substance into the cavity and then force it out. Centrifugal pumps apply a centrifugal force to push fluids through the system. Jet pumps force the substance through a nozzle in order to create velocity.
A Gerotor has an inner gear within the outer gear. The inner gear has one less tooth than the outer gear and as they rotate the gears, which interlock form a vacuum or suction-type environment and pull the liquid at a constant rate from one end to the other.1)
To see an animation of this process see: http://www.pumpschool.com/principles/ig_ani.htm OR: http://upload.wikimedia.org/wikipedia/commons/4/4b/Internal_gear_pump.gif
| Pros | Cons |
|---|---|
| High Speed2) | Pressure Limitations3): Can carry about 1-340 m3/hr4) Up to 16 bar pressure5) |
| Few moving parts6) | |
| Constant and Even Discharge7) | |
| Quiet8) |
The external gear pumps work the same way as the internal gear pumps, except they use two gears of the same size next to each other to form the suction.9)
To see an animation of this process see: http://www.pumpschool.com/principles/eg_ani.htm
| Pros | Cons |
|---|---|
| Reliable & Accurate Measurements10) | Cannot handle high temperatures11) |
| High Pressures (above 200 bar)12) | |
| High Speed13) |
Diaphragm pumps are positive displacement pumps that uses a moving diaphragm to change pressure in a chamber that will receive and then expel the liquid14) as can be seen in the following animation: http://upload.wikimedia.org/wikipedia/commons/c/c5/Membraanpomp.svg.
A major advantage of diaphragm pumps is that they do not wear out quickly as they have very few movable parts that rub against one another. In addition, they are effective pumps that work just with air.15)
“The process liquid enters the suction nozzle and then into eye (center) of a
revolving device known as an impeller. When the impeller rotates, it spins the liquid
sitting in the cavities between the vanes outward and provides centrifugal acceleration.
As liquid leaves the eye of the impeller a low-pressure area is created causing more liquid to
flow toward the inlet. Because the impeller blades are curved, the fluid is pushed in a
tangential and radial direction by the centrifugal force. This force acting inside the pump
is the same one that keeps water inside a bucket that is rotating at the end of a string.”16)
An advantage of the Centrifugal Pumps is that, unlike the displacement pumps, it flows continuously rather than filling and emptying the cavity as described above.
An image of this system can be seen at: http://media.web.britannica.com/eb-media/58/3658-004-061948E8.gif.
For more details and equations regarding Centrifugal Pumps see pages 2-6 in http://media.web.britannica.com/eb-media/58/3658-004-061948E8.gif.
Within this category there are three types of centrifugal pumps. The radial flow pumps is what is portrayed in the picture above in which the water flowing in leaves the system at a 90 degree angle. The axial flow enters and leaves at the same angle. And the mixed flow is a compromise of the two.
The Axial Flow Pump therefore operates at higher flow rates, but lower pressures than the Radial Flow Pump.
The syringe pump is designed to deliver accurate amounts, but is usually only for small amounts of medication.17)
These options are in addition to the current negative pressure pump plan - therefore these pumps can be used to pump media through the pulmonary artery or if desired to replace what is detailed below as our current negative pressure plan.
The following pump drive, pump head, and tubing combo will enable us to continue to work with our 3/8” tubing and connection plans.
With the combo we could get between .2 and 8 Liters per minute per pump head, with a maximum of two pump heads allowed (which accommodates both the requirement for about 6 L/min for the negative pressure and the 4-6 L/min for the pulmonary artery media).
In addition, the '-00' model allows for remote inputs of 4-20 mA or 0-10 V and remote outputs of 4-20 mA.
Pump drive with remote capability ($2,445/ $2,375): CP Model #: 77411-00
-this drive requires the following $110 cable: CP Model #: 77300-32
Pump drive without remote capabilities ($1,895/ $1,855); CP Model #: 77410-10
Pump heads- would want 2 ($610): CP Model #: 77601-10
Mounting Hardware ($30): CP Model #: 77601-96
I/P 73 Norprene Food Tubing : CP Model #: 06402-73
-other types of I/P 73 tubing work work as well; however, based on information given for the L/S Pump drive and heads the Norprene Food tubing appears to be most durable
The CP Model #: 77420-00 also will match the speeds we need and allows for remote capability.
However, this pump is double the price; this pump is digital as opposed to analog (which I believe means the only difference is that you choose flow rate rather than percentage of max flow rate).
This would use the same pump heads and tubing as the pump above this.
We will be using peristaltic pumps as outlined in Details on Pumps to be used for Negative Pressure.