C frame adapter
Used to connect and align the pump to the motor with registered
fits. (imperial dimensions. Called the D frame adapter in the
metric system)
C.L.A.
Center line average. A method of measuring surface finish in
the metric system. Uses microns as a unit.
Canned pump
A non seal pump with the shaft, bearings and rotor contained
in a can to prevent product leakage. Limited to pumping clean
lubricating liquids.
Capacity
Fluid flow measured in gpm, liters/min, M3/hr. etc.
Carbide
The compound formed when carbon combines with an element. The
carbides of metal are very hard and are often used as a mechanical
seal face.
Carbon bushing
Used as a restrictive bushing in flushing applications, a thermal
barrier in high temperature applications, a disaster bushing in
an A.P.I. gland and to support a deflecting shaft in many mechanical
seal applications.
Carbon/ graphite
A common mechanical seal face material chemically inert to most
fluids with the exception of oxidizers, bleaches, halogens and
a few other fluids.
Carbonizing
A reduction of hydrocarbons resulting in the formation of carbonaceous
residue that will interfere with the movement of a mechanical
seal. Often called "coking".
Carcinogen
A cancer producing substance.
Cartridge seal
A self contained assembly containing the seal, gland, sleeve,
and both stationary and rotating seal faces. Usually needs no
installation measurement. Must be used if impeller adjustments
are made. Cartridge seals are the standard for A.P.I. seal applications.
Catalyst
A chemical additive that decreases the time of a chemical reaction
with out being affected by the reaction.
Cavitate
Cavities or bubbles form in the fluid low pressure area and collapse
in a higher pressure area of the pump, causing noise, damage and
a loss of capacity.
Center line design
The pump is suspended on feet attached to the sides of the volute
instead of the bottom. Used in higher temperature (> 100?C)
pumping applications.
Centipoise
The metric system unit of viscosity.
Centistoke
The kinematic unit of viscosity. Viscosity in centipoises divided
by the liquid density at the same temperature, gives kinematic
viscosity in centistokes.
Centrifugal pump
Moves liquid with centrifugal force. Available in circular and
volute configurations.
Centrifugal separator
Sometimes called a cyclone separator. Uses centrifugal force
to throw solids out of the fluid. Does not work very well in slurry
seal applications.
Ceramic
A hard, chemically inert seal face material that includes products
refereed to as silicone carbide.
Change of state
When a liquid flashes into a vapor, solidifies, crystallizes,
cokes etc.
Chemraz?
An "elastomer like" material manufactured by Green
Tweed of England. Used to seal most solvents and other aggressive
fluids.
Chloride stress corrosion
Occurs in the 300 series of stainless steel. Caused by a combination
of tensile stress, chlorides and heat. No one knows the threshold
values.
Chrome carbide
Forms when chrome forms with carbon in the heat affected zone
during the welding of stainless steel. The use of low carbon stainless
steel is recommended in these applications.
Chrome Oxide
The passivated layer that forms on the 300 series of stainless
steel.
Circular casing
Used with centrifugal pumps that circulate fluid rather than
build head or pressure.
Clam Shell
Used to set the pitch (distance between convolutions) while heat
treating a metal bellows core.
Close coupled
The pump impeller is mounted directly on the motor shaft. There
is no separate bearing case.
Coated Face
A hard coating is plated or welded to a softer base material.
Presents problems with different thermal expansion rates, the
hard coating can "heat check" or crack. Not recommended
as a seal face material.
Coke
A hard black substance that forms when petroleum products are
over heated. It interferes with seal movement and will open the
lapped faces.
Composite
When used in the content of mechanical seal faces, it refers
to either a non metallic material or a combination of non metallic
face inserted into a metal holder.
Compression set
The elastomer changes shape when it has been exposed to too much
heat. Round O-rings come out square.
Concentric dual seal
One seal is located inside the other, with a common hard face
shared by both of them. Because of its large radial space requirement
the seal is usually limited to mixer type applications.
Concentricity
When the parts share the same center line they are concentric
to each other.
Condensate
Condensed steam.
Convection
A natural circulation of fluid. The hot fluid (lighter) rises
and the cool fluid (heavier) sinks.
Convection tank
Used to contain fluid between two mechanical seals. An enclosed
heater or cooler can be used to control the barrier or buffer
fluid temperature. Pressure or level gages can indicate which
seal has failed.
Convolution
Two metal bellows plates welded or formed together. To count
the number of convolutions in a metal bellows you count the spaces
between the bellows plates.
Cooling jacket
Surrounds the stuffing box of the pump to control the temperature
of the fluid in the stuffing box. Usually molded into the back
plate.
Corrosion resistant
Corrodes at a rate of less than 0.002 inches (0.05 mm) per year.
Coupling
Used to connect the pump to the driver. It transmits torque and
compensates for axial growth, but not for radial misalignment.
Critical speed
Any object made of an elastic material has a natural period of
vibration. When a pump rotor or shaft rotates at any speed corresponding
to its natural frequency, minor unbalances will be magnified.
These speeds are called the critical speeds.
Cryogenic
Very cold temperatures.
Cutwater
Directs the pumped liquid to the discharge piping.
Cyclone separator
A device used in some seal applications to separate solids from
liquid by utilizing centrifugal force. Not very reliable.