9. Fire Pump Theory Flashcards
From the standpoint of design, _____are the simplest of all fire apparatus pumps.
Rotary-type pumps
Page 296
To minimize the lateral thrust of large quantities of water entering the eye of the impeller, a _____ impeller may be used.
Double-suction impeller
Page 301
Because the impeller turns at a high rate of speed, a radial thrust is developed as the water is delivered to the discharge outlet. ____ in the oppose discharge volutes divert the water into two streams that are 180° apart.
Stripping edges
Page 301
The process of switching between pressure and volume is sometimes referred to as:
“Changeover”
Pace 302
Newer model centrifugal pumps may be equipped with a _____ that opens to allow overheated water to circulate between the pump and the main water tank or into the atmosphere.
Thermal relief valve
Page 306
The driver can check for excessive pump temperature manually by:
Placing a hand on the direct pump intake pipe
Page 306
At the point where the shaft passes through the pump casing, a semi-tight seal must be maintained to prevent air leaks that may interfere with pumps ability to conduct a drafting operation. _____are the most common in use today.
Mechanical seals
Page 306
The most common type of seal packing material is composed of:
Rope fibers impregnated with graphite or lead
Pace 306
Heat develops by friction where the packing rings come into contact with the shaft. In order to overcome this, a spacer, known as a ______ or _____is supplied with the packing to provide cooling.
Lantern or Slinger Ring
Page 306
_______seals may also be available for use in certain pumps. This material offers superior resistance to warping, stretching, and corrosion.
Ceramic
Page 307
Type of pump used for auxiliary systems, including compressed air foam system (CAFS) generators on some apparatus.
Hydrostatic Pump
Page 311
Some pumps are equipped with a_______ valve that serves the same function as a circulator valve by diverting a portion of the discharge water into the tank.
booster line cooling valve
Page 316
The most common type of valve is a _____ valve that permits the full flow of water through a line with a minimum friction loss.
Ball-type
Page 316
_______valves are most commonly operated by hand wheels. ______valves are most commonly operated by quarter-turn handles.
Gate
Butterfly
Page 317
Although there are several types available, the most common relief valve uses a ________.
Spring-controlled pilot valve
Page 319
