C-frame adapter: Achieving proper alignment between the pump shaft and the driver shaft is crucial for optimising pumping efficiency. One approach to aid in achieving this alignment is by using a C-frame adapter.

Calculation software: The manual calculation of fluid mechanics solutions, such as determining pump ratings, sizes, piping run lengths, diameters, and flow rates, can be a time-consuming task with numerous opportunities for errors. Fortunately, there are various software packages available that can handle complex systems with multiple components. These software solutions automate the necessary calculations, enabling users to concentrate on other aspects of their work while ensuring accurate results.

Canned pump: A canned pump is a type of pump where the armature and shaft of the motor are enclosed within a can. It is specifically designed for pumping clean lubricating fluids.

Cantilever pumps, also known as suspended pumps, are centrifugal pumps that are frequently used in sump pump applications. They are particularly useful when it is undesirable or impractical to submerge the bearings and motor of the pump in water.

Capacity: Capacity refers to the volume of liquid that a pump can move within a given unit of time. It is typically measured in units such as gallons per minute (GPM), cubic metres per second (m³/s), and so on.

Carbide: Carbide refers to a group of compounds that are formed when carbon combines with another element. These compounds are known for their exceptional hardness and are commonly utilised in applications such as seals and cutting tools for metals..

Carbon Bushing: A bushing manufactured from carbon material. It is frequently used as a thermal insulator in high-temperature applications. Additionally, it can serve as a backup bushing and provide support for a deflecting shaft in various mechanical seal applications.

Carbon/Graphite: A chemical element commonly employed in mechanical seals as part of the sealing face. Carbon possesses excellent chemical inertness when exposed to most fluids.

Carbonization: The process of producing carbon deposits on seals. This can impede the proper movement of the seal and result in leakage.

Carcinogen: Refers to any chemical substance with the potential to induce cancer.

Cartridge Seal: An integrated assembly comprising the seal, gland sleeve, and rotating seal faces. Due to its self-contained nature, it can be installed without requiring precise measurements. Cartridge seals are commonly used in API (American Petroleum Institute) seals.

Case: The pump case, also known as the volute chamber, encompasses the impeller(s) of the pump. It can be split either radially or axially for maintenance purposes.

Case Crowning: In the case of a horizontally split centrifugal pump, case crowning is a technique employed to increase the transfer of bolt load towards the case bore. This method enhances the sealing capability of the case gasket and helps prevent washout. It is particularly recommended for applications where the pump operates above 2150 psi.

Case Retiring Thickness: Over time, pump cases may experience erosion or corrosion, resulting in a decrease in wall thickness. The point at which the case thickness reaches a critical level requiring retirement is referred to as the case retiring thickness.

A catalyst is a substance that is introduced into a chemical reaction to accelerate its rate. Unlike other reactants, the catalyst remains unchanged and is not consumed during the reaction.

Cavitate: Cavitation refers to the occurrence of bubbles or voids in fluid flow applications when exposed to areas of low pressure. This phenomenon leads to a collapse in the high-pressure region of the pump, resulting in reduced capacity, increased noise, and potential damage.

Centre line design: In this pump design, the pump is mounted on feet attached to the sides of the volute, rather than the bottom. This configuration is commonly employed in pumping applications involving high temperatures.

Centipoise: Centipoise is a unit used to measure dynamic viscosity. It is equivalent to 1 millipascal-second (mPa·s).

Centistoke: The centistoke is a unit used to measure kinematic viscosity, sometimes referred to as the diffusivity of momentum. It represents the relationship between dynamic viscosity in cP (centipoise) and the density of a liquid.

Centrifugal force: Centrifugal force is an apparent force experienced by a rotating object that causes it to move away from the center of rotation. It should not be mistaken for centripetal force. This force arises from the inertia of the rotating body as its path is consistently redirected.

Centrifugal pump : A centrifugal pump is a device that facilitates fluid movement by converting rotational kinetic energy into hydrodynamic energy, thus enabling fluid flow. In this type of pump, the fluid usually enters near the center of rotation and gets accelerated by an impeller. It then moves radially outward towards a volute chamber where it exits the pump.

Centrifugal Separator: Utilizes centripetal force to separate solids from liquids.

Ceramic: Generally, ceramics refer to inorganic, nonmetallic solids. They can exist in either a crystalline or amorphous form and are produced by heating and subsequent cooling processes.

Change of State: Refers to the transition of a substance from one state to another, such as from a solid to a liquid, from a liquid to a gas, or from a solid to a gas.

Check valve: A mechanical apparatus designed to enable the passage of liquid in a single direction exclusively. It acts as a one-way valve, effectively preventing the backward flow of fluid in a pump.

Chemraz®: It  is a trademarked elastomer renowned for its exceptional chemical resistance and ability to maintain efficient elasticity. It is commonly utilized in the production of seals.

Chloride stress corrosion: Chloride stress corrosion is a phenomenon characterized by the formation of cracks in a corrosive environment. It particularly affects certain types of stainless steels and aluminium alloys when exposed to chloride substances.

Chopper pump: A pump designed with an impeller that doubles as a cutting blade. It is specifically used in applications where solid-containing fluids are present, effectively preventing pump blockage.

Chrome Carbide: Formed during the welding process of stainless steel, chrome carbide emerges in the heat affected zone when chromium combines with carbon.

Chrome oxide: A protective layer, also known as the passivated layer, that naturally forms on stainless steel surfaces. Its purpose is to inhibit further oxidation.

Circular casing: This type of casing is employed in centrifugal pumps when the pump’s purpose is to circulate fluid rather than generate pressure or head.

Clam shell: An apparatus used during the production of metal bellows to establish the desired spacing between convolutions.

Close-coupled: Refers to the configuration where the pump impeller is directly mounted onto the rotating drive shaft, eliminating the need for separate bearings.

Close-coupled pump: A close-coupled pump refers to a pump configuration where the impeller is directly mounted on the drive shaft. These pumps offer the benefit of being compact in size, although they have limitations on their maximum size.

Closed or open impeller: When it comes to impellers, there are two types: closed impellers and open impellers. A closed impeller consists of vanes enclosed within a shroud, ensuring constant contact between the impeller and the fluid. On the other hand, an open impeller lacks this shroud. Closed impellers are generally more efficient, but they can be more prone to clogging if the process fluid contains solid particles.

Enclosed Impeller: A type of impeller characterized by having its vanes fully enclosed between two shrouds, positioned at the front and back.

Coated Face: When the surface of a seal is plated or welded onto the seal’s base, typically using a softer material. However, this design may encounter challenges if the two metals involved have different rates of thermal expansion.

Coke: A fuel produced through the heating or “cracking” of petroleum products. It has the potential to cause issues with pump seals.

Colebrook Equation: In the field of fluid mechanics, understanding the friction resulting from the interaction between a fluid and the internal surface of a pipe is crucial. The Colebrook equation (also known as the Colebrook and White equation) is a formula employed to calculate the friction factor of a fluid flowing within a pipe.

Composite: In the context of mechanical seals, this term denotes either a non-metallic material or a combination of a non-metallic face inserted into a metallic base material.

Compression set: Rubber seals become “compression set” when they are overheated. Elastomeric material loses its shape and takes on a new shape. Can cause leaks in seals.

Concentric dual seal: A dual seal where one seal is situated concentrically within another seal. Used when radial dimensions are not limiting.

Concentricity: When rotating parts each share the same axis of rotation, they are said to be concentric with each other.

Condensate: The fluid formed after a vapour has condensed. For example, water is a condensate of steam.

Constant level oiler: A means to maintain the correct oil level in a bearing housing. Automatically replenishes oil as it is used.

Convection: Fluid movement caused by local differences in density. Areas of hot fluid (less dense) will naturally rise, while colder fluid (denser) will sink.

Convection tank: A container used to hold the fluid between two mechanical seals. Integrated heater / coolers are used to control the temperature of the barrier fluid.

Convolution : During construction of metal bellows plates, when they are welded together, they form a convolution.

Cooling jacket: An extra casing surrounding the stuffing box to control the temperature of the process fluid within the stuffing box.

Corebox: Metal parts that are cast have an outer“pattern” – the pattern that is found on the outer surface of the casting, and an inner “corebox” – the pattern that is found on the inside of the casting

Corrosion resistant: Corrosion resistant material must corrode at less than the following rates: less than 0.002 inches (0.05 mm) per year.

Coupling: A connection between the pump shaft and the motor shaft. Misalignment can be compensated for axially, but not radially.

Cover: In a radial split pump, it’s the part of the pump that completes the case.

Critical speed: Objects that are elastic (e.g. O-rings) will have natural resonant frequencies. When a pump / shaft rotates at this frequency, minor imbalances will be magnified. The speed where these natural frequencies occur are called critical speeds.

Cryogenic: Very low temperatures.

Cutwater: DA device that directs the process fluid to the pump discharge pipe.

Cutwater diameter: The cutwater diameter is an important measurement in a centrifugal pump. It is used to determine the appropriate B-gap and limit pressure pulsations and forces to reasonable levels.

CV coefficient: The flow coefficient of a mechanical device that is an indicator of its efficiency at allowing fluid flow. It describes the relationship between the pressure drop across an opening and the flow rate.

Cyclone separator: A device that separates solids from liquids by using centrifugal force.

Related Links

• Pump Glossary
• Pump info