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Booster pump
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 Front view of Russian oxygen booster pump | |
| Uses | Increasing the pressure of a fluid |
|---|---|
| Related items | Compressor |
A booster pump is a machine which increases the pressure of a fluid. It may be used with liquids or gases, and the construction details vary depending on the fluid. A gas booster is similar to a gas compressor, but generally a simpler mechanism which often has only a single stage of compression, and is used to increase pressure of a gas already above ambient pressure. Two-stage boosters are also made.[1] Boosters may be used for increasing gas pressure, transferring high pressure gas, charging gas cylinders and scavenging.
Water pressure
[edit] | The examples and perspective in this section deal primarily with the United States and do not represent a worldwide view of the subject. (January 2019) |
On new construction and retrofit projects, water pressure booster pumps are used to provide adequate water pressure to upper floors of high rise buildings. The need for a water pressure booster pump can also arise after the installation of a backflow prevention device (BFP), which is currently mandated in many municipalities[where?] to protect the public water supplies from contaminants within a building entering the public water supply. The use of BFPs began after The Clean Water Act was passed. These devices can cause a loss of 12 PSI, and can cause flushometers on upper floors not to work properly. After pipes have been in service for an extended period, scale can build up on the inside surfaces which will cause a pressure drop when the water flows.
Water pressure booster construction and function
[edit]Booster pumps for household water pressure are usually simple electrically driven centrifugal pumps with a non-return valve. They may be constant speed pumps which switch on when pressure drops below the low pressure set-point and switch off when pressure reaches the high set-point, or variable speed pumps which are controlled to maintain a constant output pressure.
Constant speed pumps are switched on by a normally closed low-pressure switch and will content to run until the pressure rises to open the high pressure switch. They will cycle whenever enough water is used to cause a pressure drop below the low set point. An accumulator in the upstream pipeline will reduce cycling.
Variable speed pumps use pressure feedback to electronically control motor speed to maintain a reasonably constant discharge pressure. Most applications run off AC mains current and use an inverter to control motor speed.
Installations that provide water to highrise buildings may need boosters at several levels to provide acceptably consistent pressure on all floors. In such a case independent boosters may be installed at various levels, each boosting the pressure provided by the next lower level. It is also possible to boost once to the maximum pressure required, and then to use a pressure reducer at each level. This method would be used if there is a holding tank on the roof with gravity feed to the supply system.[2]
Fire sprinkler booster pumps
[edit]Multi-story buildings equipped with fire sprinkler systems may require a large booster pump to deliver sufficient water pressure and volume to upper floors in the event of a fire. Such pumps are often powered by a diesel engine dedicated to this purpose. The engine needs a fuel tank and an automatic controller that will start the booster pump when it is needed. A small auxiliary electrically powered booster pump (called a "jockey pump") is often included in the system to maintain the sprinkler pipes at sufficient pressure, without requiring startup of the large diesel engine.
Any emergency system must be periodically tested and maintained to ensure its reliability. A diesel engine must be started and operated for testing, and a battery bank for the starting motor must be maintained or replaced periodically. In recent years, a larger electrical pump with substantial battery backup may be substituted for the diesel engine, reducing but not eliminating the need for maintenance.
Gas pressure
[edit]
Gas pressure boosting may be used to fill storage cylinders to a higher pressure than the available gas supply, or to provide production gas at pressure higher than line pressure. Examples include:
- Breathing gas blending for underwater diving where the gas is to be supplied from high-pressure cylinders, as in scuba, scuba replacement and surface-supplied mixed gas diving, where the component gases are blended by partial pressure addition to the storage cylinders, and the mixture storage pressure may be higher than the available pressure of the components.[3]
- Helium reclaim systems, where the heliox breathing gas exhaled by a saturation diver is piped back to the surface, oxygen is added to make up the required composition, and the gas is boosted to the appropriate supply pressure, filtered, scrubbed of carbon dioxide, and returned to the gas distribution panel to be supplied to the diver again,[4] or returned to high pressure storage
- Workshop compressed air is usually provided at a pressure suited to the majority of the applications, but some may need a higher pressure. A small booster can be effective to provide this air.[5]
Gas booster construction and function
[edit]
Gas booster pumps are usually piston or plunger type compressors. A single-acting, single-stage booster is the simplest configuration, and comprises a cylinder, designed to withstand the operating pressures, with a piston which is driven back and forth inside the cylinder. The cylinder head is fitted with supply and discharge ports, to which the supply and discharge hoses or pipes are connected, with a non-return valve on each, constraining flow in one direction from supply to discharge. When the booster is inactive, and the piston is stationary, gas will flow from the inlet hose, through the inlet valve into the space between the cylinder head and the piston. If the pressure in the outlet hose is lower, it will then flow out and to whatever the outlet hose is connected to. This flow will stop when the pressure is equalized, taking valve opening pressures into account.[1]
Once the flow has stopped, the booster is started, and as the piston withdraws along the cylinder, increasing the volume between the cylinder head and the piston crown, the pressure in the cylinder will drop, and gas will flow in from the inlet port. On the return cycle, the piston moves toward the cylinder head, decreasing the volume of the space and compressing the gas until the pressure is sufficient to overcome the pressure in the outlet line and the opening pressure of the outlet valve. At that point, the gas will flow out of the cylinder via the outlet valve and port.
There will always be some compressed gas remaining in the cylinder and cylinder head spaces at the top of the stroke. The gas in this "dead space" will expand during the next induction stroke, and only after it has dropped below the supply gas pressure, more supply gas will flow into the cylinder. The ratio of the volume of the cylinder space with the piston fully withdrawn, to the dead space, is the "compression ratio" of the booster, also termed "boost ratio" in this context. Efficiency of the booster is related to the compression ratio, and gas will only be transferred while the pressure ratio between supply and discharge gas is less than the boost ratio, and delivery rate will drop as the inlet to delivery pressure ratio increases.
Delivery rate starts at very close to swept volume when there is no pressure difference, and drops steadily until there is no effective transfer when the pressure ratio reaches the maximum boost ratio.[1]
Compression of gas will cause a rise in temperature. The heat is mostly carried out by the compressed gas, but the booster components will also be heated by contact with the hot gas. Some boosters are cooled by water jackets or external fins to increase convectional cooling by the ambient air, but smaller models may have no special cooling facilities at all. Cooling arrangements will improve efficiency, but will cost more to manufacture.
Boosters to be used with oxygen must be made from oxygen-compatible materials, and use oxygen-compatible lubricants to avoid fire.[1]
Configurations
[edit]- Single stage, single acting: There is one booster cylinder, which pressurizes the gas in one direction of piston movement, and refills the cylinder on the return stroke.
- Single stage, double acting: There are two booster cylinders, which operate alternately, with each one pressurizing gas while the other is refilling. The cylinders each pressurize gas-fed directly from the supply, and the delivered gas from each is combined at the outlets. The cylinders work in parallel and have the same bore.
- Two stage, double acting: There are two cylinders, which operate alternately, each pressurising gas while the other is refilling, but the second stage has a smaller bore and is filled by the gas pressurised by the first stage, and it pressurises the gas further. The stages operate in series, and the gas passes though both of them in turn.
Power sources
[edit]
Gas boosters may be driven by an electric motor, hydraulics, low or high pressure air, or manually by a lever system.
Compressed air
[edit]Those powered by compressed air are usually linear actuated systems, where a pneumatic cylinder directly drives the compression piston, often in a common housing, separated by one or more seals. A high pressure pneumatic drive arrangement may use the same pressure as the output pressure to drive the piston, and a low pressure drive will use a larger diameter piston to multiply the applied force.[1]
Low pressure air
[edit]A common arrangement for low pressure air powered boosters is for the booster pistons to be direct coupled with the drive piston, on the same centreline. The low pressure cylinder has a considerably larger section area than the high pressure cylinders, in proportion to the pressure ratio between the drive and boosted gas. A single action booster of this type has a boost cylinder on one end of the power cylinder, and a double action booster has a boost cylinder on each end of the power cylinder, and the piston rod has a drive piston in the middle and a booster piston on each end.[1]
Oxygen boosters require some design features which may not be necessary in boosters for less reactive gases. It is necessary to ensure that drive air, which may not be sufficiently clean for safe contact with high pressure oxygen, cannot leak past the seals into the booster cylinder, or high pressure oxygen can not leak ito the drive cylinder. This can be done by providing a space between the low pressure cylinder and high pressure cylinder that is vented to atmosphere, and the piston rod is sealed on each side where it passes through this space. Any gas leaks from either cylinder past the rod seals escapes harmlessly into the ambient air.[1]
A special case for gas powered boosters is where the booster uses the same gas supply to power the booster and as the gas to be boosted. This arrangement is wasteful of gas and is most suitable for use to provide small quantities of higher pressure air where large quantities of lower pressure air are already available. This system is sometimes known as a "bootstrap" booster.[1]
High pressure
[edit]Electrical
[edit]
- C1: cylinder
- P: piston
- T: trunnion
- B: base frame
- C: connecting rod
- G: gearbox
- M: electric motor
- E: eccentric drive
Electrically powered boosters may use a single or three-phase AC motor drive. The high speed rotational output of the motor must be converted to lower speed reciprocating motion of the pistons. One way this has been done (Dräger and Russian KN-3 and KN-4 military boosters) is to connect the motor to a worm drive gearbox with an eccentric output shaft driving a connecting rod which drives the double-ended piston via a central trunnion. This system is well suited to a double acting booster, either with single-stage boost by parallel connected cylinders with the same bore, or two-stage cylinders of different bores connected in series. Some of these boosters allow for the connecting rod to be disconnected and a pair of long levers to be fitted for manual operation in emergencies or where electrical power is not available.[1]
A booster can also resemble a single or multistage piston compressor driven by a crankshaft by a belt drive from an electric motor.[5]
Manual
[edit]
Manual boosters have been made with the configuration described above, either with a single vertical lever or with a seesaw styled double ended horizontal lever, and also with two parallel vertically mounted cylinders, much like the lever-operated diver's air pumps used for the early standard diving dress but with much smaller bore to allow two operators to generate high pressures.[1]
Manufacturers
[edit]High pressure gas boosters are manufactured by Haskel, MPS Technology, Dräger, Gas Compression Systems, Atlas Copco, and others. Rugged and unsophisticated models (KN-3 and KN-4) were manufactured for the Soviet Armed Forces and surplus examples are now used by technical divers as they are relatively inexpensive and are supplied with a comprehensive spares and tool kit.[6][5][1]
References
[edit]- ^ a b c d e f g h i j k Harlow, Vance (2002). Improvised and Low Cost HP Gas Boosters. Warner, New Hampshire: Airspeed press.
- ^ משאבות טבולות לביוב
- ^ Beresford, M.; Southwood, P. (2006). CMAS-ISA Normoxic Trimix Manual (4th ed.). Pretoria, South Africa: CMAS Instructors South Africa.
- ^ Crawford, J. (2016). "8.5.1 Helium recovery systems". Offshore Installation Practice (revised ed.). Butterworth-Heinemann. pp. 150–155. ISBN 9781483163192.
- ^ a b c "What is a booster compressor?". www.atlascopco.com. Retrieved 6 March 2025.
- ^ "Gas Booster". www.mpstechnology.it. Retrieved 13 May 2020.
Booster pump
View on Grokipediafrom Grokipedia
Overview and History
Definition and Basic Function
A booster pump is a mechanical device designed to increase the pressure of a fluid—either a liquid or a gas—within an existing piping or distribution system, thereby ensuring sufficient flow rates and delivery to endpoints such as fixtures or downstream processes.[5][6] Unlike primary pumps that generate initial flow from a static source, booster pumps operate as auxiliary units that amplify pressure in systems where inlet conditions are inadequate, such as low municipal supply or long-distance transmission lines.[3] The primary function of a booster pump is to address pressure deficiencies by drawing in fluid at low pressure and imparting energy to elevate it to operational levels, maintaining consistent performance without disrupting the overall system flow.[7] This secondary role distinguishes booster pumps from standalone primary pumps, as they rely on an upstream source to provide initial flow and do not create motion from zero head; instead, they enhance momentum to compensate for friction losses, elevation gains, or demand fluctuations.[3] In practice, booster pumps are integrated into water supply networks from wells or municipal lines and gas pipelines, where they prevent flow interruptions and support end-use requirements like irrigation or compression.[2] Typical installations achieve pressure increases ranging from 20 to 60 PSI above inlet conditions, for example boosting an incoming 20-50 PSI supply to 60-100 PSI at the outlet to meet standard residential or industrial thresholds.[8] In a household setting, a booster pump might elevate low municipal pressure to improve shower output and faucet performance during peak usage.[7] Similarly, in extended pipelines, it sustains fluid velocity over distances, ensuring reliable transport in water distribution or gas transfer systems.[5]Historical Development
The concept of booster pumps traces its roots to ancient hydraulic technologies, such as Archimedes' screw pump developed around the 3rd century BC, which facilitated water lifting but lacked the pressure-boosting specificity of modern designs.[9] Specific booster pump applications emerged during the Industrial Revolution in the 19th and early 20th centuries, as steam-powered systems enabled pressurized fluid transport in emerging urban and industrial infrastructures.[9] A pivotal early milestone occurred in 1919, when the town of Sackville, New Brunswick, installed one of the first electric booster pumps—a 40-horsepower unit housed in a dedicated pump-house—to enhance water pressure for municipal supply and fire-fighting needs.[10] In 1923, the Byron Jackson Company demonstrated the inaugural use of centrifugal booster pumps in oil pipelines, including the world's first automatic booster station, which revolutionized long-distance fluid transport by maintaining consistent pressure without constant manual oversight.[9] Following World War II, booster pumps saw widespread adoption in municipal water systems, driven by rapid suburban expansion and the need for reliable pressure in growing distribution networks.[11] The 1950s marked a surge in booster pump demand due to urbanization and the rise of high-rise construction, where systems like hydropneumatic tanks and pressure-reducing valves were integrated to deliver water to upper floors amid increasing building heights.[12] The 1970s energy crises further catalyzed innovations, prompting the development of more efficient booster designs to address rising operational costs and resource constraints in water and industrial applications.[13] During the 1970s and 1980s, multi-stage centrifugal booster pumps gained prominence for their ability to achieve higher pressures through sequential impeller stages, improving performance in demanding environments like municipal and irrigation systems.[14] In the 2000s, the integration of variable frequency drives (VFDs) into booster pumps became a standard advancement, allowing dynamic speed control to match demand and reduce energy consumption by up to 50% in variable-load scenarios such as water distribution.[15] Entering the 2020s, booster pumps have incorporated smart sensors and Internet of Things (IoT) connectivity for real-time monitoring of parameters like vibration, pressure, and flow, enabling predictive maintenance and remote optimization in urban water networks.[16] As of 2025, advancements include AI-enhanced IoT systems for advanced predictive maintenance and automated optimization, contributing to a global booster pump market projected to reach approximately $4.3 billion.[17][18]Design and Components
Key Components
A booster pump's core functionality relies on several essential hardware elements designed to accelerate or compress fluids while maintaining system integrity under elevated pressures. The primary fluid-moving component is typically an impeller in centrifugal designs, consisting of curved blades mounted on a rotating shaft that imparts kinetic energy to the incoming fluid, thereby increasing its velocity and subsequent pressure upon deceleration.[19] In positive displacement variants, a piston or plunger serves this role, reciprocating within a cylinder to trap and force a fixed volume of fluid through the system with each stroke.[20] Surrounding these is the pump housing or casing, a robust enclosure that directs fluid flow and withstands the generated pressures, often featuring volutes or diffusers to convert velocity into static pressure efficiently.[21] Inlet and outlet ports facilitate fluid entry and exit, commonly equipped with check valves to prevent backflow and maintain pressure differentials once the pump cycles off.[22] Auxiliary components enhance reliability and automation; pressure sensors or switches monitor system conditions and trigger pump activation when pressure drops below a set threshold, ensuring on-demand operation.[23] Seals, including mechanical or diaphragm types, prevent leakage around the shaft and moving parts, critical for both liquid and gas applications to avoid contamination or efficiency losses.[24] The drive mechanism, usually an electric motor, provides rotational power to the impeller or reciprocating assembly, with coupling to the shaft for torque transmission.[19] Material selection prioritizes durability and compatibility with the handled fluid. For water booster pumps, stainless steel (such as 304 or 316 grades) offers superior corrosion resistance, particularly in environments with minerals or chemicals, while cast iron provides a cost-effective alternative for less aggressive conditions.[25][26] In high-pressure gas applications, specialized alloys like Hastelloy or titanium are employed to resist corrosion from reactive gases and endure extreme conditions.[27] Multi-stage booster pumps incorporate sequential impellers aligned in series within the casing, where each stage incrementally boosts pressure; multiple stages can achieve significantly higher pressure outputs, depending on impeller design and motor power.[28] In water systems, an expansion tank is often integrated to accommodate thermal expansion of the fluid, reducing stress on components and preventing pressure surges during temperature fluctuations.[29]Construction Variations
Booster pumps exhibit significant construction variations tailored to the type of fluid being handled. For liquids such as water or oil, which are incompressible, designs commonly feature horizontal centrifugal configurations with robust impellers and volutes to manage steady flow rates. These incorporate mechanical seals and lubricated bearings optimized for higher viscosities and minimal cavitation risks.[30] In contrast, gas booster pumps, suited for compressible media like compressed air or natural gas, often utilize vertical reciprocating or piston-based assemblies to accommodate volume expansion and pressure fluctuations, with dry-running seals and low-friction bearings designed for lower viscosities and potential gas leakage prevention.[31] Pressure requirements drive further adaptations in booster pump construction. Single-stage models, typically employing a solitary impeller within a compact casing, are built for moderate pressure boosts, using standard cast iron or stainless steel housings for durability in general service. Multi-stage variants stack multiple impellers in series within an elongated barrel or inline body to achieve higher pressures, with reinforced diffusers and shafts capable of handling very high pressures, often exceeding several thousand PSI in specialized gas applications, often featuring optional stainless steel construction for corrosion resistance.[32][33][34] Environmental conditions necessitate specific build modifications for reliability and safety. Submersible booster pumps are constructed with fully sealed, waterproof casings and integrated motors using 300-series stainless steel shells and hermetic designs to operate immersed in wells or tanks, preventing ingress of contaminants. For hazardous settings like oil and gas operations, explosion-proof enclosures encase the motor and electrical components in certified, flame-retardant housings compliant with standards such as ATEX or NEC, minimizing ignition risks from volatile atmospheres. Compact inline designs, with end-suction and discharge ports aligned for direct piping integration, utilize space-efficient vertical or horizontal orientations ideal for HVAC systems.[35][36][37] Certain configurations highlight specialized assembly approaches. Triplex setups arrange three pumps in parallel on a shared skid or baseplate, often with vertical multistage elements and vibration-dampening mounts, enabling redundant operation for continuous duty. Modular assemblies facilitate scalability by allowing interchangeable pump modules and control panels to expand from small residential capacities of 1-5 GPM to commercial-scale systems exceeding 100 GPM, using standardized connectors for phased upgrades.[38][39]Operation and Principles
Working Mechanism
A booster pump functions by drawing fluid into its inlet under low pressure, where mechanical energy is then imparted to the fluid either through the rotation of impellers that accelerate it or the reciprocation of pistons that compress it, resulting in delivery at higher pressure through the outlet.[40] This process ensures consistent flow and pressure augmentation in systems where natural supply is insufficient.[41] The operational stages generally comprise suction, during which the pump creates a low-pressure zone to draw fluid into the chamber; boosting, where the imparted energy increases the fluid's velocity or compresses its volume to elevate pressure head; and discharge, expelling the fluid while designed to minimize cavitation risks that could disrupt flow.[40] In the boosting phase, components such as impellers contribute to energy transfer by accelerating the fluid.[19] Central to this mechanism is Bernoulli's principle, which posits that in steady, incompressible flow without friction, the sum of pressure head, velocity head, and elevation head remains constant along a streamline: $ P + \frac{1}{2} \rho v^2 + \rho g z = \text{constant} $.[42] Booster pumps apply external mechanical work to alter this balance, increasing total energy; volutes or diffusers subsequently convert the gained kinetic energy into static pressure energy for efficient output.[42] The added energy is quantified by the pump head $ H $, defined as the work done per unit weight of fluid, approximated as
where $ P_{\text{out}} $ and $ P_{\text{in}} $ are the outlet and inlet pressures, $ \rho $ is the fluid density, and $ g $ is gravitational acceleration; this derivation stems from Bernoulli's equation under assumptions of equal inlet-outlet velocities and elevations, highlighting the pressure increase as equivalent to a height of fluid column.[43]
Safety mechanisms, including pressure switches that monitor inlet conditions and trigger automatic shutoff upon detecting low pressure indicative of dry running, protect the pump from damage due to insufficient fluid supply.[44]
Performance Characteristics
Booster pumps exhibit performance defined by key metrics such as flow rate, pressure ratio, and efficiency, which vary based on design and application. Flow rate is commonly expressed in gallons per minute (GPM) for liquid-handling booster pumps or standard cubic feet per minute (SCFM) for gas systems, with typical capacities ranging from low flows under 100 GPM for small units to over 1,000 GPM for larger installations.[45] Pressure ratio, also known as the boost factor, indicates the multiplication of inlet pressure to outlet pressure and varies depending on the system's requirements and pump configuration.[46] Efficiency, a measure of how effectively the pump converts input power to hydraulic output, generally falls between 50% and 85% for centrifugal booster pumps, while positive displacement types achieve higher efficiencies, often exceeding 85% across a broader operating range due to their fixed displacement mechanism.[45][47] Several factors influence booster pump output, including Net Positive Suction Head (NPSH) requirements, duty cycle, and head-capacity relationships. NPSH, specifically the required NPSH (NPSHR), must be met by the available NPSH (NPSHA) with a safety margin of at least 25% to prevent cavitation, which can degrade performance and cause damage; NPSHR values are plotted on performance curves and increase with flow rate for centrifugal designs.[45] Duty cycle—whether continuous (sustained operation) or intermittent (periodic on/off)—affects pump selection and longevity, with many booster pumps rated for continuous duty in stable systems but requiring cooling provisions for intermittent use to avoid overheating.[48] Head-capacity curves, provided by manufacturers, depict the trade-off between flow rate and total dynamic head (pressure expressed in feet of fluid), showing decreasing head as flow increases, along with overlaid efficiency and power curves to identify the best efficiency point (BEP).[45] Pump efficiency is calculated as , where power output represents the hydraulic energy imparted to the fluid and power input is the mechanical or electrical energy supplied. The hydraulic output power is given by:
with as fluid density (kg/m³), as gravitational acceleration (9.81 m/s²), as volumetric flow rate (m³/s), and as total head (m); this yields power in kilowatts, while input power is derived from motor ratings in kilowatts or brake horsepower.[45]
Variable frequency drives (VFDs) enhance performance by enabling speed adjustment to match system demand, improving part-load efficiency through reduced energy consumption per the affinity laws, which scale power cubically with speed.[45] Over time, however, internal wear from erosion, corrosion, or mechanical degradation can reduce efficiency, with reports indicating drops of up to 20% in severely worn centrifugal pumps without regular maintenance.[49]