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)
- Center line average. A method of measuring surface finish in
the metric system. Uses microns as a unit.
- A non seal pump with the shaft, bearings and rotor contained
in a can to prevent product leakage. Limited to pumping clean
- Fluid flow measured in gpm, liters/min, M3/hr.
- The compound formed when carbon combines with an element. The
carbides of metal are very hard and are often used as a mechanical
- 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.
- A common mechanical seal face material chemically inert to
most fluids with the exception of oxidizers, bleaches, halogens
and a few other fluids.
- A reduction of hydrocarbons resulting in the formation of
carbonaceous residue that will interfere with the movement of a
mechanical seal. Often called "coking".
- A cancer producing substance.
- 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
- A chemical additive that decreases the time of a chemical
reaction with out being affected by the reaction.
- 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.
- The metric system unit of viscosity.
- The kinematic unit of viscosity. Viscosity in centipoises
divided by the liquid density at the same temperature, gives
kinematic viscosity in centistokes.
- Moves liquid with centrifugal force. Available in circular and
- Sometimes called a cyclone separator. Uses centrifugal force
to throw solids out of the fluid. Does not work very well in
slurry seal applications.
- 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,
- An "elastomer like" material manufactured by Green Tweed of
England. Used to seal most solvents and other aggressive
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.
- 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.
- The passivated layer that forms on the 300 series of stainless
- Used with centrifugal pumps that circulate fluid rather than
build head or pressure.
- Used to set the pitch (distance between convolutions) while
heat treating a metal bellows core.
- The pump impeller is mounted directly on the motor shaft.
There is no separate bearing case.
- 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
- A hard black substance that forms when petroleum products are
over heated. It interferes with seal movement and will open the
- 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.
- 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
- When the parts share the same center line they are concentric
to each other.
- A natural circulation of fluid. The hot fluid (lighter) rises
and the cool fluid (heavier) sinks.
- 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.
- 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.
- Surrounds the stuffing box of the pump to control the
temperature of the fluid in the stuffing box. Usually molded into
the back plate.
- Corrodes at a rate of less than 0.002 inches (0.05 mm) per
- Used to connect the pump to the driver. It transmits torque
and compensates for axial growth, but not for radial
- 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.
- Directs the pumped liquid to the discharge piping.
- A device used in some seal applications to separate solids
from liquid by utilizing centrifugal force. Not very
For information about my CD,
with over 600 Seal & Pump Subjects
Link to Mc Nally home page