Finger pumps push a series of rods against a flexible tubing in sequence, forcing fluid along the tube. In this pump the fluid moves from left to right.
Since nothing but the tube actually touches the fluid, the fluid can be kept clean so this pump is often found in medical applications, pumping blood or other fluids.
The individual fingers can be operated by a rotating camshaft above them, by individual solenoids electronically actuated in sequence, or by other methods. Fireboat
In the course of producing the All About Pumps educational software program, the author visited scores of fire stations, fire museums and fire boats, and talked to dozens and dozens of firefighters. This entry in the Internet Glossary of Pumps has now been dedicated to the 300+ New York City firefighters who were killed September 11th, 2001 in the collapse of the World Trade Center’s Twin Towers, and the thousands they tried to save, but were unable to. America lost the bravest of the brave that day, but thousands of lives were saved by their heroic actions in the moments following the terrorist attack.
Every major harbor has one or more fireboats to protect the docks and ships where ground-based fire vehicles cannot go.
Originally (late 1800’s) these boats were made from old, converted tugboats. Within a few decades they had proved their worth and specially-designed fireboats began to be built.
Certainly the most famous fireboat of all time is the FIRE FIGHTER of New York City, which began service in 1938 and still answers the call.
FIRE FIGHTER was designed by William Francis Gibbs, who also designed the ocean liners AMERICA and UNITED STATES.
Four 5000 GPM De Laval two-stage centrifugal pumps provide a total pumping capacity of 20,000 gallons per minute at 150 PSI. They can also be connected in series to provide 10,000 GPM at 300 PSI.
W. F. Gibbs also designed a land-based fire truck — the most powerful ever built — called the Super Pumper, which served NYC from 1965 to 1982. It was built by Mack Trucks, and could feed 35 hoselines at once.
FishTank Diaphragm Pump
This pump is designed for continous operation. It is simple and reliable.
The motor operates directly off of house current at 60 cycles per second (signified by the sine wave in the upper right corner).
The electric current flows through thin wires around an iron core. The wire is wrapped around one side of the core, many hundreds of times.
Whenever the current reverses (60 times per second) the magnetic flux created by the current is reversed. This alternately pushes and pulls the armature.
The armature moves the diaphragm in and out directly. The valves are forced open and closed by the air pressure created by the movement of the diaphragm. Force Pump, Double Acting
This pump is more efficient that a single-acting force pump such as a simple Lift Pump or a hand-operated Bilge Pump.
Each stroke of the piston fills one chamber and empties another, which nearly doubles the flow rate (less the volume of the piston rod) over a single-acting force pump. It also smooths the flow.
From the outside this pump can take many forms, but the basic principal of operation will be identical.