A pump is a device that moves fluids ( liquids or gases ), or sometimes slurries , by mechanical action, typically converted from electrical energy into hydraulic energy.
59-554: Mechanical pumps serve in a wide range of applications such as pumping water from wells , aquarium filtering , pond filtering and aeration , in the car industry for water-cooling and fuel injection , in the energy industry for pumping oil and natural gas or for operating cooling towers and other components of heating, ventilation and air conditioning systems. In the medical industry , pumps are used for biochemical processes in developing and manufacturing medicine, and as artificial replacements for body parts, in particular
118-430: A centrifugal pump . The fluid enters along the axis or center, is accelerated by the impeller and exits at right angles to the shaft (radially); an example is the centrifugal fan , which is commonly used to implement a vacuum cleaner . Another type of radial-flow pump is a vortex pump. The liquid in them moves in tangential direction around the working wheel. The conversion from the mechanical energy of motor into
177-460: A building's ability to protect against external harm events (such as weather , home invasion , etc.), or may indicate that its internal installations (such as appliances , stairs , etc.) are safe (not dangerous or harmful) for its inhabitants. Discussions of safety often include mention of related terms. Security is such a term. With time the definitions between these two have often become interchanged, equated, and frequently appear juxtaposed in
236-464: A curved spiral wound around of thickness half x , though in reality it is manufactured in a single casting. This shaft fits inside a heavy-duty rubber sleeve, of wall thickness also typically x . As the shaft rotates, the rotor gradually forces fluid up the rubber sleeve. Such pumps can develop very high pressure at low volumes. Named after the Roots brothers who invented it, this lobe pump displaces
295-408: A desire to die. There is a distinction between products that meet standards, that are safe, and that merely feel safe. The highway safety community uses these terms: Normative safety is achieved when a product or design meets applicable standards and practices for design and construction or manufacture, regardless of the product's actual safety history. Substantive or objective safety occurs when
354-528: A gentle pumping process ideal for transporting shear-sensitive media. Devised in China as chain pumps over 1000 years ago, these pumps can be made from very simple materials: A rope, a wheel and a pipe are sufficient to make a simple rope pump. Rope pump efficiency has been studied by grassroots organizations and the techniques for making and running them have been continuously improved. Impulse pumps use pressure created by gas (usually air). In some impulse pumps
413-425: A higher hydraulic-head and lower flow-rate. The device uses the water hammer effect to develop pressure that lifts a portion of the input water that powers the pump to a point higher than where the water started. The hydraulic ram is sometimes used in remote areas, where there is both a source of low-head hydropower, and a need for pumping water to a destination higher in elevation than the source. In this situation,
472-423: A home's external threats and protection from its internal structural and equipment failures (see Meanings, above) are not two types of safety but rather two aspects of a home's steady state. In the world of everyday affairs, not all goes as planned. Some entity's steady state is challenged. This is where security science , which is of more recent date, enters. Drawing from the definition of safety, then: Security
531-402: A low flow rate, the total head rise and high torque associated with this pipe would mean that the starting torque would have to become a function of acceleration for the whole mass of liquid in the pipe system. Water well pump A water well pump is a pump that is used in extracting water from a water well . Deep well pumps extract groundwater from subterranean aquifers, offering
590-517: A myriad of markets across the world. Triplex pumps with shorter lifetimes are commonplace to the home user. A person who uses a home pressure washer for 10 hours a year may be satisfied with a pump that lasts 100 hours between rebuilds. Industrial-grade or continuous duty triplex pumps on the other end of the quality spectrum may run for as much as 2,080 hours a year. The oil and gas drilling industry uses massive semi-trailer-transported triplex pumps called mud pumps to pump drilling mud , which cools
649-732: A particular ANSI standard. Many government agencies set safety standards for matters under their jurisdiction, such as: Product safety testing, for the United States, is largely controlled by the Consumer Product Safety Commission. In addition, workplace related products come under the jurisdiction of the Occupational Safety and Health Administration (OSHA), which certifies independent testing companies as Nationally Recognized Testing Laboratories (NRTL), see. The European Commission provides
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#1732790550369708-574: A pulsation damper. The increase in moving parts and crankshaft load is one drawback. Car washes often use these triplex-style plunger pumps (perhaps without pulsation dampers). In 1968, William Bruggeman reduced the size of the triplex pump and increased the lifespan so that car washes could use equipment with smaller footprints. Durable high-pressure seals, low-pressure seals and oil seals, hardened crankshafts, hardened connecting rods, thick ceramic plungers and heavier duty ball and roller bearings improve reliability in triplex pumps. Triplex pumps now are in
767-430: A reliable source of water independent of municipal networks. These pumps, often submersible and powered by electricity, can access water reserves located much deeper than shallow wells, ensuring a consistent supply even during periods of drought. They include different kinds of pumps, most of them submersible pumps : The pump replaces the use of a bucket and pulley system to extract water. Safety Safety
826-474: A return line back to the suction line or supply tank, provides increased safety . A positive-displacement pump can be further classified according to the mechanism used to move the fluid: These pumps move fluid using a rotating mechanism that creates a vacuum that captures and draws in the liquid. Advantages: Rotary pumps are very efficient because they can handle highly viscous fluids with higher flow rates as viscosity increases. Drawbacks: The nature of
885-414: A slight increase in internal leakage as the pressure increases prevents a truly constant flow rate. A positive-displacement pump must not operate against a closed valve on the discharge side of the pump, because it has no shutoff head like centrifugal pumps. A positive-displacement pump operating against a closed discharge valve continues to produce flow and the pressure in the discharge line increases until
944-443: A standard of insurance to the quality and unharmful function of an object or organization. It is used in order to ensure that the object or organization will do only what it is meant to do. It is important to realize that safety is relative. Eliminating all risk , if even possible, would be extremely difficult and very expensive. A safe situation is one where risks of injury or property damage are low and manageable. When something
1003-425: Is a more complicated type of rotary pump that uses two or three screws with opposing thread — e.g., one screw turns clockwise and the other counterclockwise. The screws are mounted on parallel shafts that often have gears that mesh so the shafts turn together and everything stays in place. In some cases the driven screw drives the secondary screw, without gears, often using the fluid to limit abrasion. The screws turn on
1062-400: Is a type of positive-displacement pump. It contains fluid within a flexible tube fitted inside a circular pump casing (though linear peristaltic pumps have been made). A number of rollers , shoes , or wipers attached to a rotor compress the flexible tube. As the rotor turns, the part of the tube under compression closes (or occludes ), forcing the fluid through the tube. Additionally, when
1121-405: Is called safe, this usually means that it is safe within certain reasonable limits and parameters. For example, a medication may be safe, for most people, under most circumstances, if taken in a certain amount. A choice motivated by safety may have other, unsafe consequences. For example, frail elderly people are sometimes moved out of their homes and into hospitals or skilled nursing homes with
1180-414: Is how they operate under closed valve conditions. Positive-displacement pumps physically displace fluid, so closing a valve downstream of a positive-displacement pump produces a continual pressure build up that can cause mechanical failure of pipeline or pump. Dynamic pumps differ in that they can be safely operated under closed valve conditions (for short periods of time). Such a pump is also referred to as
1239-675: Is involved, and track record indicates some of the areas of theory that are relevant. (In the US, persons with a state license in Professional Engineering in Electrical Engineering are expected to be competent in this regard, the foregoing notwithstanding, but most electrical engineers have no need of the license for their work.) Safety is often seen as one of a group of related disciplines: quality, reliability, availability, maintainability and safety. (Availability
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#17327905503691298-435: Is passed through it. This causes an electromagnetic force that moves the liquid. Applications include pumping molten solder in many wave soldering machines, pumping liquid-metal coolant, and magnetohydrodynamic drive . A positive-displacement pump makes a fluid move by trapping a fixed amount and forcing (displacing) that trapped volume into the discharge pipe. Some positive-displacement pumps use an expanding cavity on
1357-583: Is sometimes not mentioned, on the principle that it is a simple function of reliability and maintainability.) These issues tend to determine the value of any work, and deficits in any of these areas are considered to result in a cost, beyond the cost of addressing the area in the first place; good management is then expected to minimize total cost. Safety measures are activities and precautions taken to improve safety, i.e. reduce risk related to human health. Common safety measures include: Today there are multiple scientific journals focusing on safety research. Among
1416-497: Is sometimes used in developing new types of mechanical pumps. Mechanical pumps may be submerged in the fluid they are pumping or be placed external to the fluid. Pumps can be classified by their method of displacement into electromagnetic pumps , positive-displacement pumps , impulse pumps , velocity pumps , gravity pumps , steam pumps and valveless pumps . There are three basic types of pumps: positive-displacement, centrifugal and axial-flow pumps. In centrifugal pumps
1475-429: Is supposed to do" is defined in terms of public codes and standards, associated architectural and engineering designs , corporate vision and mission statements, and operational plans and personnel policies. For any organization, place, or function, large or small, safety is a normative concept. It complies with situation-specific definitions of what is expected and acceptable. Using this definition, protection from
1534-425: Is that safety issues can be readily deduced. In fact, safety issues have been discovered one by one, over more than a century in the case mentioned, in the work of many thousands of practitioners, and cannot be deduced by a single individual over a few decades. A knowledge of the literature, the standards and custom in a field is a critical part of safety engineering. A combination of theory and track record of practices
1593-472: Is the process or means, physical or human, of delaying, preventing, and otherwise protecting against external or internal, defects, dangers, loss, criminals, and other individuals or actions that threaten, hinder or destroy an organization’s "steady state," and deprive it of its intended purpose for being. Using this generic definition of safety it is possible to specify the elements of a security program. Safety can be limited in relation to some guarantee or
1652-402: Is the simplest form of rotary positive-displacement pumps. It consists of two meshed gears that rotate in a closely fitted casing. The tooth spaces trap fluid and force it around the outer periphery. The fluid does not travel back on the meshed part, because the teeth mesh closely in the center. Gear pumps see wide use in car engine oil pumps and in various hydraulic power packs . A screw pump
1711-511: Is the state of being "safe", the condition of being protected from harm or other danger. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk . The word 'safety' entered the English language in the 14th century. It is derived from Latin salvus , meaning uninjured, in good health , safe. There are two slightly different meanings of "safety". For example, " home safety " may indicate
1770-504: The 9/11 attacks in 2001, many people chose to drive rather than fly, despite the fact that, even counting terrorist attacks, flying is safer than driving. Perceived risk discourages people from walking and bicycling for transportation, enjoyment or exercise, even though the health benefits outweigh the risk of injury. Perceived safety can drive regulation which increases costs and inconvenience without improving actual safety. Also called social safety or public safety, security addresses
1829-480: The artificial heart and penile prosthesis . When a pump contains two or more pump mechanisms with fluid being directed to flow through them in series, it is called a multi-stage pump . Terms such as two-stage or double-stage may be used to specifically describe the number of stages. A pump that does not fit this description is simply a single-stage pump in contrast. In biology, many different types of chemical and biomechanical pumps have evolved ; biomimicry
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1888-539: The potential energy of flow comes by means of multiple whirls, which are excited by the impeller in the working channel of the pump. Generally, a radial-flow pump operates at higher pressures and lower flow rates than an axial- or a mixed-flow pump. These are also referred to as all-fluid pumps . The fluid is pushed outward or inward to move fluid axially. They operate at much lower pressures and higher flow rates than radial-flow (centrifugal) pumps. Axial-flow pumps cannot be run up to speed without special precaution. If at
1947-511: The claim that this will improve the person's safety. The safety provided is that daily medications will be supervised, the person will not need to engage in some potentially risky activities such as climbing stairs or cooking, and if the person falls down, someone there will be able to help the person get back up. However, the end result might be decidedly unsafe, including the dangers of transfer trauma , hospital delirium , elder abuse , hospital-acquired infections , depression, anxiety, and even
2006-504: The defined safety regulations. A major American standards organization is the American National Standards Institute (ANSI). Usually, members of a particular industry will voluntarily form a committee to study safety issues and propose standards. Those standards are then recommended to ANSI, which reviews and adopts them. Many government regulations require that products sold or used must comply with
2065-686: The desired direction. In order for suction to take place, the pump must first pull the plunger in an outward motion to decrease pressure in the chamber. Once the plunger pushes back, it will increase the chamber pressure and the inward pressure of the plunger will then open the discharge valve and release the fluid into the delivery pipe at constant flow rate and increased pressure. Pumps in this category range from simplex , with one cylinder, to in some cases quad (four) cylinders, or more. Many reciprocating-type pumps are duplex (two) or triplex (three) cylinder. They can be either single-acting with suction during one direction of piston motion and discharge on
2124-405: The direction of flow of the fluid changes by ninety degrees as it flows over an impeller, while in axial flow pumps the direction of flow is unchanged. An electromagnetic pump is a pump that moves liquid metal , molten salt , brine , or other electrically conductive liquid using electromagnetism . A magnetic field is set at right angles to the direction the liquid moves in, and a current
2183-476: The drill bit and carries the cuttings back to the surface. Drillers use triplex or even quintuplex pumps to inject water and solvents deep into shale in the extraction process called fracking . Typically run on electricity compressed air, these pumps are relatively inexpensive and can perform a wide variety of duties, from pumping air into an aquarium , to liquids through a filter press . Double-diaphragm pumps can handle viscous fluids and abrasive materials with
2242-446: The fluid trapped between two long helical rotors, each fitted into the other when perpendicular at 90°, rotating inside a triangular shaped sealing line configuration, both at the point of suction and at the point of discharge. This design produces a continuous flow with equal volume and no vortex. It can work at low pulsation rates, and offers gentle performance that some applications require. Applications include: A peristaltic pump
2301-423: The gas trapped in the liquid (usually water), is released and accumulated somewhere in the pump, creating a pressure that can push part of the liquid upwards. Conventional impulse pumps include: Instead of a gas accumulation and releasing cycle, the pressure can be created by burning of hydrocarbons. Such combustion driven pumps directly transmit the impulse from a combustion event through the actuation membrane to
2360-410: The head of the cylinder. In the suction stroke, the plunger retracts and the suction valves open causing suction of fluid into the cylinder. In the forward stroke, the plunger pushes the liquid out of the discharge valve. Efficiency and common problems: With only one cylinder in plunger pumps, the fluid flow varies between maximum flow when the plunger moves through the middle positions, and zero flow when
2419-418: The line bursts, the pump is severely damaged, or both. A relief or safety valve on the discharge side of the positive-displacement pump is therefore necessary. The relief valve can be internal or external. The pump manufacturer normally has the option to supply internal relief or safety valves. The internal valve is usually used only as a safety precaution. An external relief valve in the discharge line, with
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2478-519: The most common. Probably the most common individual response to perceived safety issues is insurance, which compensates for or provides restitution in the case of damage or loss. System safety and reliability engineering is an engineering discipline. Continuous changes in technology, environmental regulation and public safety concerns make the analysis of complex safety-critical systems more and more demanding. A common fallacy, for example among electrical engineers regarding structure power systems,
2537-865: The most popular ones are Safety Science and Journal of Safety Research. The goal of this research is to identify, understand, and mitigate risks to human health and well-being in various environments. This involves systematically studying hazards, analyzing potential and actual accidents, and developing effective strategies to prevent injuries and fatalities. Safety research aims to create safer products, systems, and practices by incorporating scientific, engineering, and behavioral insights. Ultimately, it seeks to enhance public safety, reduce economic losses, and improve overall quality of life by ensuring that both individuals and communities are better protected from harm. A number of standards organizations exist that promulgate safety standards. These may be voluntary organizations or government agencies. These agencies first define
2596-678: The other, or double-acting with suction and discharge in both directions. The pumps can be powered manually, by air or steam, or by a belt driven by an engine. This type of pump was used extensively in the 19th century—in the early days of steam propulsion—as boiler feed water pumps. Now reciprocating pumps typically pump highly viscous fluids like concrete and heavy oils, and serve in special applications that demand low flow rates against high resistance. Reciprocating hand pumps were widely used to pump water from wells. Common bicycle pumps and foot pumps for inflation use reciprocating action. These positive-displacement pumps have an expanding cavity on
2655-480: The plunger is at the end positions. A lot of energy is wasted when the fluid is accelerated in the piping system. Vibration and water hammer may be a serious problem. In general, the problems are compensated for by using two or more cylinders not working in phase with each other. Centrifugal pumps are also susceptible to water hammer. Surge analysis , a specialized study, helps evaluate this risk in such systems. Triplex plunger pumps use three plungers, which reduces
2714-417: The presence of the associated hazards that are known, expected, or reasonably assumed to exist during a planned activity and any likely contingencies associated with it. Safety is generally interpreted as implying a real and significant impact on risk of death, injury or damage to property. In response to perceived risks many interventions may be proposed with engineering responses and regulation being two of
2773-404: The pulsation relative to single reciprocating plunger pumps. Adding a pulsation dampener on the pump outlet can further smooth the pump ripple , or ripple graph of a pump transducer. The dynamic relationship of the high-pressure fluid and plunger generally requires high-quality plunger seals. Plunger pumps with a larger number of plungers have the benefit of increased flow, or smoother flow without
2832-473: The pump fluid. In order to allow this direct transmission, the pump needs to be almost entirely made of an elastomer (e.g. silicone rubber ). Hence, the combustion causes the membrane to expand and thereby pumps the fluid out of the adjacent pumping chamber. The first combustion-driven soft pump was developed by ETH Zurich. A hydraulic ram is a water pump powered by hydropower. It takes in water at relatively low pressure and high flow-rate and outputs water at
2891-468: The pump into the discharge pipe. This conversion of kinetic energy to pressure is explained by the First law of thermodynamics , or more specifically by Bernoulli's principle . Dynamic pumps can be further subdivided according to the means in which the velocity gain is achieved. These types of pumps have a number of characteristics: A practical difference between dynamic and positive-displacement pumps
2950-513: The pump requires very close clearances between the rotating pump and the outer edge, making it rotate at a slow, steady speed. If rotary pumps are operated at high speeds, the fluids cause erosion, which eventually causes enlarged clearances that liquid can pass through, which reduces efficiency. Rotary positive-displacement pumps fall into five main types: Reciprocating pumps move the fluid using one or more oscillating pistons, plungers, or membranes (diaphragms), while valves restrict fluid motion to
3009-404: The ram is often useful, since it requires no outside source of power other than the kinetic energy of flowing water. Rotodynamic pumps (or dynamic pumps) are a type of velocity pump in which kinetic energy is added to the fluid by increasing the flow velocity. This increase in energy is converted to a gain in potential energy (pressure) when the velocity is reduced prior to or as the flow exits
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#17327905503693068-520: The real-world safety history is favorable, whether or not standards are met. Perceived or subjective safety refers to the users' level of comfort and perception of risk, without consideration of standards or safety history. For example, traffic signals are perceived as safe, yet under some circumstances, they can increase traffic crashes at an intersection. Traffic roundabouts have a generally favorable safety record yet often make drivers nervous. Low perceived safety can have costs. For example, after
3127-424: The risk of harm due to intentional criminal acts such as assault, burglary or vandalism. Because of the moral issues involved, security is of higher importance to many people than substantive safety. For example, a death due to murder is considered worse than a death in a car crash, even though in many countries, traffic deaths are more common than homicides. Operational safety is the absence of unacceptable risk in
3186-572: The safety standards, which they publish in the form of codes. They are also Accreditation Bodies and entitle independent third parties such as testing and certification agencies to inspect and ensure compliance to the standards they defined. For instance, the American Society of Mechanical Engineers (ASME) formulated a certain number of safety standards in its Boiler and Pressure Vessel Code (BPVC) and accredited TÜV Rheinland to provide certification services to guarantee product compliance to
3245-405: The same sentence. Readers are left to conclude whether they comprise a redundancy. This confuses the uniqueness that should be reserved for each by itself. When seen as unique, as we intend here, each term will assume its rightful place in influencing and being influenced by the other. Safety is the condition of a "steady state" of an organization or place doing what it is supposed to do. "What it
3304-421: The shafts and drive fluid through the pump. As with other forms of rotary pumps, the clearance between moving parts and the pump's casing is minimal. Widely used for pumping difficult materials, such as sewage sludge contaminated with large particles, a progressing cavity pump consists of a helical rotor, about ten times as long as its width. This can be visualized as a central core of diameter x with, typically,
3363-488: The suction side and a decreasing cavity on the discharge side. Liquid flows into the pump as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. The volume is constant through each cycle of operation. Positive-displacement pumps, unlike centrifugal , can theoretically produce the same flow at a given rotational speed no matter what the discharge pressure. Thus, positive-displacement pumps are constant flow machines . However,
3422-468: The suction side and a decreasing cavity on the discharge side. Liquid flows into the pumps as the cavity on the suction side expands and the liquid flows out of the discharge as the cavity collapses. The volume is constant given each cycle of operation and the pump's volumetric efficiency can be achieved through routine maintenance and inspection of its valves. Typical reciprocating pumps are: The positive-displacement principle applies in these pumps: This
3481-399: The tube opens to its natural state after the passing of the cam it draws ( restitution ) fluid into the pump. This process is called peristalsis and is used in many biological systems such as the gastrointestinal tract . Plunger pumps are reciprocating positive-displacement pumps. These consist of a cylinder with a reciprocating plunger. The suction and discharge valves are mounted in
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