mud pump displacement formula quotation

Rig pump output, normally in volume per stroke, of mud pumps on the rig is  one of important figures that we really need to know because we will use pump out put figures to calculate many parameters such as bottom up strokes,  wash out depth, tracking drilling fluid, etc. In this post, you will learn how to calculate pump out put for triplex pump and duplex pump in bothOilfield and Metric Unit.

Pumps are often considered as a machine which will provide a required flow and pressure, however in reality the performance of a pump is dictated by a performance curve detailing how the pump will provide a range of flows at differing pressures.

Pumps provide a differential pressure and flow according to their installation. As there are 3 main families of pumps being Centrifugal, Rotary Positive Displacement and Reciprocating Positive Displacement which have different characteristics dependent on the circumstances they face.

Pumps are a simple machine which provide a performance based on the system it works in, as most pumps do not have a control interface unless fitted with a pressure transducer and variable frequency drive (VFD) and must be manually commissioned onsite.

A pumps performance will be inline with the pressure losses in the system, with pumps producing a differential flow and pressure based on the conditions at the inlet. A pump curve is a graphical representation of what flows and differential pressures can be produced by a pump.

As 90% of problems with pumps are caused by the system they are installed in, it is important to note that pump selection is just part of the process of selecting a pump which is right for the process.

The numbers at the end of the curve is the impeller diameter, which is trimmed to acheive the required flow and pressure. The more an impeller is trimmed the higher the impact on a pumps efficiency as the gap between the outside of the impeller and casing is larger creating inefficiencies.

Although a pump curve shows the various duty points that a pump can achieve, operating the pump in some of the areas of operation can lead to many problems.

As you can see in the illustration across and above pump curve there is a point typically midway curve known as the Best Efficiency Point which is the most efficient point at which the pump can be operated at.

As you can see in the below illustration if the pump is operated on the left it can mean low bearing life, mechanical seal failure and heavy vibration.

If a pump is operated too far left on its curve there is no allowance for extra capacity should there be miscalculation in system pressures. Too far to the right and there is the risk of cavitation which can destroy the pump casing and impeller very quickly and cause the liquid to boil. Good practice is to always have a safety margin maybe 10% towards the left of the duty point to ensure the pump can operate as required, as a pumps performance can always be reduced, but not increased.

This is because a positive displacement pump flow is proportional to rpm and does not decrease with pressure like a centrifugal pump. A PD pump curve usually has a separate axis detailing viscosity, where the pump will show a flow against viscosity as per the graph below.

The NPSH pump curve shows the Net Positive Suction Pressure Required (NPSH) in Metres (M) to deliver the duty point. The NPSH of a centrifugal pump is typically stable on the left side of the axis, where a pump is producing the highest pressure but lowest flow. After the Best Efficiency Point the NPSH curve steadily increases before rising sharply at the end of the performance curve where the pump will cavitate if operated. The NPSH curve is more relevant to rotary centrifugal pumps and less relevant to positive displacement pumps which are less likely to operate end of curve and cavitate. In the below curve an NPSH of 3.32M is required to deliver the required performance.

A system curve provides a graphical image of the pump head required to move fluid around the designed system. The system curve considers the losses of all the required components at various flows within the system, as well as the static head. A system curve will be plotted on to a pump curve, and where the two intersect determines the flow and pressure which will be produced in the system.

A pump efficiency curve shows the efficiency of a pump across the range of flows and pressures produced by a pump. On the left hand side of the curve the efficiency will range from 0 to a maximum of around 85% efficiency before decreasing after approximately mid performance curve. Ideally a pump should be operated as close as possible to its BEP for maximum component life, and minimal wear.

Outside of the Best Efficiency Point (BEP) the pumps performance will suffer and if operated inefficiently can damage itself, leading to its destruction within minutes.

Pump curves are shown at full motor speed, but if the speed of the pump is reduced the curve will reduce. The outer edge of the curve will step inwards towards the axis on all sides meaning a reduction in both outlet pressure and flow. Reducing a pumps speed is more efficient than reducing an impeller diameter as the clearances between the impeller tip and casing remain small. 2 pumps operating at 50% capacity will save more energy than one pump operating at full capacity.

The power a pump uses to deliver a specific performance varies according to where the pump operates on its curve. Pumps are often fitted with larger motors than required for the duty point, to ensure should the pump operate towards the end of its curve it will continue to operate as required and not trip. As you can see in the below curve on the far left the pump absorbs (uses) just over 3.5Kw, and at duty point to deliver the flow required a power of 7.09kw is required. The power absorbed by the pump continues to rise after the duty point, meaning in practice a pump should be fitted with a motor of at least 7.5kw to cover end of pump curve.

FlowFlow Varies significantly. Particularly if pressure losses are miscalculated.Flow is proportional to RPM, and pump is known to be a volumetric pump with very predictable behavior.

Efficiency vs ViscosityEfficiency drops significantly with viscosity, with a handling limit of around 300cstAccepts up to 50,000cst. Pump performance increases with viscosity

Viscosity can vary significant with certain fluids such as oils and it is important to ensure the figure quoted is correct. Many fluids have a viscosity quoted at 20°C or 60°C which can be far from the actual pumping temperature especially in cooling applications where the pump is required to work prior to the oil being heated.

The Minimum Continuous Safe Flow is the minimum amount of a flow a centrifugal pump can do without sustaining issues such as cavitation, or excess wear and is often a figure used to design operating speeds, and bypass control valves in processes where pumps may be running continuously such as boiler feed applications, cooling or in lubrication applications.

Motors on centrifugal pumps revolutions are set by the number of poles in the motor. The more poles a motor has the slower it will operate at. Increasing the number of poles in a motor can help pumps to produce more flow at lower pressures, and gain from a reduction in the NPSH required, suffer from less wear and tear, and utilize a smaller powered motor. If a higher pressure is required and lower flow pumps will operate at higher RPM to generate the pressures required.

Changing the number of poles in motor is not the only way to change pump speed. Pumps can also be set at individual rpms if used through an inverter or mechanical variator. Positive displacement pumps will usually use a gearbox with a pump operating at full motor speed in order to ensure the pump operates at a set RPM.

Some applications will require a pump to operate for a short amount of time, and others for 24/7 such as in cooling at which point a low motor speed will be chosen. A PD pump may have a 2 pole motor rather than a higher pole due to the starting torque. Care should also be taken as motors can be listed as having a high RPM but in actual fact the rpm may be rated as less from the motor. North Ridge Pump curves are specified to the exact RPM of the motor rather than using a general figure.Motor PolesRPM at 50hzRPM at 60hz

This means that depending on the class used for testing the head can vary between +- 0% to +-7% and flow between 0% to +-9% which requires careful consideration during pump selection. This is often why margins are added to requested performance.

The pump affinity laws are a set of formula which can be used to determine a pumps performance when a change is made such as speed, or impeller diameter to the produced flow and pressure with a high degree of accuracy.

As the shaft speed or the impeller diameter is altered, the flow will change by the same amount. If the speed of a pump is reduced by 20% the flow at the same head will also decrease by 20%.

When it comes to pumping terminology, one crucial term to know is GPM — a measurement that will help you determine if you’re choosing the right pump. So what is GPM, and how do you calculate it?

GPM stands for gallons per minute and is a measurement of how many gallons a pump can move per minute. It is also referred to as flow rate. GPM is variable based on another measurement known as the Head, which refers to the height the water must reach to get pumped through the system. It is also referred to as flow rate. GPM is variable based on another measurement known as the Head, which refers to the height the water must reach to get pumped through the system.

Pumps are typically measured by their GPM at a certain Head measurement. For example, a pump specification may read 150 GPM at 50 Feet of Head, which means the pump will work at 150 gallons per minute when pumping water at a height of 50 feet.

The GPM formula is 60 divided by the number of seconds it takes to fill a one gallon container. So if you took 10 seconds to fill a gallon container, your GPM measurement would be 6 GPM (60/10 seconds = 6 GPM). To most accurately calculate GPM, you use the pressure tank method and formula. For this calculation, you need to know the specifications of your pressure tank, including how many gallons it holds, the gallon drawdown and the PSI. The manufacturer specifies the gallon drawdown. Once you have that information, as well as a stopwatch to keep time, follow these steps:

GPM identifies the unique capabilities of a pump so you can select the right one for your specific needs. If you need a pump for a larger public area such as a golf course, marina or lake, you will need a pump with a much higher GPM than one used for your home’s well. Plus, choosing the correct pump is essential for reducing your costs and increasing your pump’s lifespan.

At GeoForm International, we are a leading manufacturer of high-quality submersible pumps, dredges, digester packages and aerators, all of which are made in the U.S. With our pump expertise, we know just how essential GPM is in the pumping and dredging industry from how much equipment costs to how long jobs will take.

When it comes to pumping terminology, one crucial term to know is GPM — a measurement that will help you determine if you’re choosing the right pump. So what is GPM, and how do you calculate it?

GPM stands for gallons per minute and is a measurement of how many gallons a pump can move per minute. It is also referred to as flow rate. GPM is variable based on another measurement known as the Head, which refers to the height the water must reach to get pumped through the system. It is also referred to as flow rate. GPM is variable based on another measurement known as the Head, which refers to the height the water must reach to get pumped through the system.

Pumps are typically measured by their GPM at a certain Head measurement. For example, a pump specification may read 150 GPM at 50 Feet of Head, which means the pump will work at 150 gallons per minute when pumping water at a height of 50 feet.

The GPM formula is 60 divided by the number of seconds it takes to fill a one gallon container. So if you took 10 seconds to fill a gallon container, your GPM measurement would be 6 GPM (60/10 seconds = 6 GPM). To most accurately calculate GPM, you use the pressure tank method and formula. For this calculation, you need to know the specifications of your pressure tank, including how many gallons it holds, the gallon drawdown and the PSI. The manufacturer specifies the gallon drawdown. Once you have that information, as well as a stopwatch to keep time, follow these steps:

GPM identifies the unique capabilities of a pump so you can select the right one for your specific needs. If you need a pump for a larger public area such as a golf course, marina or lake, you will need a pump with a much higher GPM than one used for your home’s well. Plus, choosing the correct pump is essential for reducing your costs and increasing your pump’s lifespan.

At GeoForm International, we are a leading manufacturer of high-quality submersible pumps, dredges, digester packages and aerators, all of which are made in the U.S. With our pump expertise, we know just how essential GPM is in the pumping and dredging industry from how much equipment costs to how long jobs will take.

(1kg) The work done by the liquid, that is, the increase in energy of the unit weight of liquid after passing through the pump. It is represented by the letter H and is usually expressed by the height m of the liquid column.

The pump head H=z+hw z is the height difference of the pumping height, that is, the water level from the inlet to the water surface at the exit. Hw is the head loss, including the Darcy formula or Xie Cai formula for calculating the head loss hf and the local head loss hw hf along the path.

Pump head is an important working energy parameter of the pump. For the industry, the pump head calculation formula is a very common technical data. Below, the world factory pump valve network introduces the pump head calculation formula in detail.

The head is usually the maximum height that the pump can lift, and is indicated by H. The most commonly used pump head calculation formula is H = (p2-p1) / ρg + (c2-c1) / 2g + z2-z1.

Among them, H - head, m; p1, p2 - the pressure of the liquid at the inlet and outlet of the pump, Pa; c1, c2 - the flow rate of the fluid at the inlet and outlet of the pump, m / s; z1, z2 - the height of the inlet and outlet , m; ρ - liquid density, kg / m3; g - gravity acceleration, m / s2.

Generally, a centrifugal clean water pump with a specific number of revolutions ns of 130 to 150 is used. The flow rate of the water pump should be 1.1 to 1.2 times the rated flow rate of the chiller (1.1 for a single unit and 1.2 for two units in parallel).

When two (or more) pumps are arranged in serial their resulting pump performance curve is obtained by adding theirheads at the same flow rate as indicated in the figure below.

Centrifugal pumps in series are used to overcome larger system head loss than one pump can handle alone. for two identical pumps in series the head will be twice the head of a single pump at the same flow rate - as indicated with point 2.

With a constant flowrate the combined head moves from 1 to 2 - BUTin practice the combined head and flow rate moves along the system curve to point 3. point 3 is where the system operates with both pumps running

When two or more pumps are arranged in parallel their resulting performance curve is obtained by adding the pumps flow rates at the same head as indicated in the figure below.

Centrifugal pumps in parallel are used to overcome larger volume flows than one pump can handle alone. for two identical pumps in parallel and the head kept constant - the flow rate doubles compared to a single pump as indicated with point 2

Note! In practice the combined head and volume flow moves along the system curve as indicated from 1 to 3. point 3 is where the system operates with both pumps running

In practice, if one of the pumps in parallel or series stops, the operation point moves along the system resistance curve from point 3 to point 1 - the head and flow rate are decreased.

We provide hydraulic components & repair services for industrial applications like paper mills, saw mills, steel mills, recycling plants, oil & gas applications and mobile applications, including construction, utility, mining, agricultural and marine equipment. This includes hydraulic pumps, motors, valves, servo/prop valves, PTOs, cylinders & parts.

Reading a pump curve will tell you how a pump will perform in regards to pressure head and flow. A pump composite curve cover will include the pump performance curves, horsepower curves, and NPSH required. A curve is defined for a specific operating speed (rpm) and a specific inlet/outlet diameter.

On our example chart main vertical Y-axis we have head pressure and on the horizontal X-axis, we have the flow rate. Basically, the head is pressure and the flow rate is how much water the pump can move.

Head is useful because it evaluates a pump’s capacity to do a job. Most pump applications involve moving fluid to a higher level. If you have to pump a liquid up 30 feet and your pump doesn’t have at least 30 feet of head, then there is no chance it will work. Your pump will need at least 30 ft. plus the friction loss to get the required flow at the required discharge point.

Head pressure will vary with the fluids you are pumping. For example, we have bought a pump that can provide 150 feet of head (45.72m). Then we use it to pump water, the pressure will be around 54.25 psi (4.485 bar). But if we use it to pump milk then the pressure will be around 56.15 psi (4.64 bar). The pressure will vary depending on the liquid used but the height it can be moved by the pump will remain the same.

A pump’s flow rate is how much fluid it can transport within a given time. Knowing this, you can assess if an existing system is working efficiently or not. If you know the flow rate you should be achieving and yet your system is not performing, then you can take the necessary action to fix the issue.

The best way to read your flow rate with a flow meter. It’s a simple device that can measure the amount of fluid passing through a pipeline. Attach this to your discharge pipe, as close as possible to your pump and it should give you a reliable reading of your flow rate. It is important to outfit your system with meters to check on its performance over time. Years on someone else will make changes to the system and will be able to read the meters added to the system to correct any problems introduced to the system by their changes.

The performance curve will be different for each pump and some will suit your system needs better than others. You will usually see on the chart as the flow rate increases, the head pressure decreases.

When selecting a larger pump, as long as your system requirements are on or below the performance line, the pump can be considered. Performance can be changed on existing pumps by using smaller impellers or variable frequency drives to better suit your requirements.

The rotor or impeller is the core part and it converts the mechanical energy into pressure energy which directly determines the transport capacity and the hydraulic performances of a centrifugal or slurry pump. The fluid enters the impeller through the eye then it is pushed by the vanes/blades as the fluid passes the channel.

On most centrifugal-style pumps, the impeller size can be changed as needed. The diameter of the impeller will change how much water can be moved. On some pump performance charts, you will see multiple performance curves which give the details of the pump for different diameter impellers. The diameter of the impeller will be listed at the end of the line. This gives you a powerful variable that you can change to get to peak performance for your application.

BHP (brake horsepower) curves indicate the horsepower required to operate a pump at a given point on the performance curve. The lines on the horsepower curve correspond to the performance curves above them and, like the head-flow curve, the different lines correspond to different impeller sizes. This information is useful to ensure that the selected motor is the correct size and is also used when calculating power consumption costs.

The pump performance curve also provides efficiency curves. These efficiency curves intersect with the head-flow curves and are labeled with percentages. The efficiency varies throughout the operating range.

Some curves will also mark the Best Efficiency Point (B.E.P.). This is the point on a pump’s performance curve that corresponds to the highest efficiency and is usually between 80-85% of the shutoff head. At this point, the impeller is subjected to minimum radial force promoting a smooth operation with low vibration and noise, leading to less maintenance and longer equipment life.

Some pump manufacturers will provide separate charts for operating the pump at different rotational speeds. You can then compare the performance to get a close match and then find an electrical motor that will suit this. Typically, higher rotational speeds lead to more service and maintenance so where possible it’s good practice to choose a lower speed pump that meets your system’s requirements.

The third part of the pump curve is the Net Positive Suction Head Required (NPSHr) curve. The NPSHr curve provides information about the suction characteristics of the pump at different flows. For more information on NPSH, please see here.

The x-axis is still measured in inflow units (gallons per minute), but the y-axis is now measured in feet of NPSHr. Each point along the curve identifies the NPSHr required by the pump at a certain flow to avoid cavitation issues that would be damaging to the pump and would have a negative impact on overall pump performance.

Cavitation is where the pressure at the inlet of the pump reaches a low enough point that the water begins to boil, this creates rapidly expanding and collapsing air bubbles which will gradually destroy the surface of the pump and casing, requiring a new pump.

The heavier the material (or higher specific gravity SG), the faster the speed needed to move the material through the pipeline, to prevent settling at the bottom of the slurry pipeline. This is often referred to as critical line velocity, The dredge operator has to monitor the velocity of the slurry based upon the width of the slurry pipeline and the specific gravity of the materials being pumped.

This means the pipeline size and pump selection are very important when doing initial calculations. Simply changing the pipe size in the field will impact the project and need to be compensated for.

If you are pumping dense solids, like rocks, it is important to get finer solids as well such as dirt because your finer materials will help lift up the heavier solids and assist in transporting rocks all of the way down the pipeline without clogging up, this is in conjunction with having enough turbulence in the flow of your slurry pipeline.