mud pump dampener function quotation

Mud Pump Pulsation Dampener is usually installed on the discharge line to reduce the fluctuation of pressure and displacement of the drilling mud pump.

Mud Pump Pulsation Dampener is a pneumatic device built into the outflow line of each UUD pump to dampen the pressure fluctuations resulting from the action of the pump. Although presented as a surge tank, this device is really a device that can be tuned to greatly diminish the output pulsations transmitted downstream from the mud pump. Unfortunately, the effectiveness of the pulsation dampener is a function of both output pump pressure and frequency of the pump pulsations.

For more information about pulsation dampeners, we sat down with Brandon Dalrymple and Nathan Ackeret fromBlacoh Fluid Control(manufacturer of pulsation dampeners, surge suppressors, and inlet stabilizers), and asked them to answer a few of our customers’ most common questions about pulsation dampeners.

Pulsation dampeners absorb the energy from the pulse wave created by a positive displacement pump, much like a shock absorber on a vehicle. Absorbing those pulse waves protects pipe welds and supports, and system components from damage due to pressure or excess movement.

A pulsation dampener creates an area of low pressure in the system with enough volume to absorb the pulsation. The pulsation dampener has a membrane with a "cushion" of compressible gas/air behind it that flexes to absorb the pulse, allowing a laminar flow downstream of the dampener.

Pulsation dampeners are commonly used wherever a positive displacement pump discharges flow in an unsteady manner, and where the pulse is not desired for the piping system. Air operated double diaphragm, metering and hose/peristaltic pumps typically benefit from a pulsation dampener.

The type of pulsation dampener used is typically defined by where they are placed in the system, and what they need to do. For example, "pulsation dampeners" are on the downstream side of the pump, "inlet stabilizers" are on the inlet side of the pump, and an accumulator or "surge suppressor" is used next to a valve or other device that restricts the flow in a system.

This video shows where you would place an inlet stabilizer, and how it is used to reduce the pulsation with an air operated diaphragm pump in suction lift conditions.

A properly serviced pulsation dampener is critical for your mud pumps’ efficiency, safety, and performance. Unfortunately, there aren’t many resources available to educate personnel on executing safe and effective servicing procedures. Please review the following steps with your personnel for safe pulsation dampener maintenance.

Should you or your personnel have any questions regarding pulsation dampener maintenance, please don’t hesitate to ask. Sigma is more than happy to help you to ensure safe and proper care is being completed on your pulsation dampening equipment.

Pulsation Dampener (Surge damper) is installed on the discharge pipeline of the mud pump to balance the peak value of the high-pressure fluid pressure of the mud pump, so as to stabilize the pressure and reduce losses.

The installation of properly sized pulsation dampeners minimize vessel costs while protecting the pump and piping system and improving process efficiency and accuracy.

A pulsation dampener reduces or eliminates the variations in pressure and flow produced by reciprocating pumps. In many applications, low frequency pressure waves cause problems within a given piping system and/or process. Eccentric, cam-driven pumps are probably the most commonly applied for services that require pulsation dampening, e.g., metering pumps and reciprocating (power) pumps.

Pulsation dampeners are found in a variety of designs, but for our purposes we will focus on only gas-charged pulsation dampeners, which rely on a calculated volume of compressed gas, usually Nitrogen, which is alternately compressed and expanded in synchronization with the pump plunger to reduce or eliminate pressure pulsations. This gas volume is normally separated from the process fluid by a flexible membrane. Common membrane designs include elastomeric bladders, PTFE diaphragms, PTFE bellows or stainless steel bellows.

Pressure waves or pulses are a consequence of the alternating acceleration and deceleration of fluid velocity corresponding to the travel of the piston or plunger. The pattern and amplitude of these pulses varies with pump configuration, specifically the number and size of pistons, as well as fluid compressibility factors.

It is precisely the fluid volume above mean on the discharge cycle of each stroke, which induces these pressure pulsations into a piping system. The number of pistons offered by the pump-given that all are of identical diameter and equally phased-displace a known peak volume above mean. These constants may be influenced by fluid compressibility, but for the purpose of this explanation we’ll assume none at this point. A pulsation dampener absorbs only that portion of piston displacement above mean flow, and then stores it momentarily before discharging it during the portion of the cycle below mean flow (on the suction stroke).

A simplex pump displaces a volume of fluid above mean that is equal to about 60 percent of total displacement. A duplex pump displaces a lower fluid volume above mean, approximately half that of a simplex pump. Pumps of three or more pistons of equal diameter, stroke length and proportionally phased will always present a very small fluid volume above mean to the piping system. A triplex pump, for example, produces about a 4 percent peak, as long as fluid compressibility factors and pump efficiencies are not at issue.

These smaller fluid volumes are accounted for by the crank angle of each of the cylinders. Triplex pumps are offset by 120-deg. Quadruplex pumps are set apart at 90-deg offsets; quintuplex pumps are offset 72-deg, and so on. It is the resulting overlap in pulses that yield the smaller fluid volumes above mean.

Fluid velocity gradients follow the same mechanical velocity gradients of the eccentric cam that drives the piston(s). Halfway through the piston’s forward travel (discharge stroke), fluid velocity between the discharge check valve and the pulsation dampener begins to decay. The corresponding drop in pressure causes the membrane inside the dampener to expand since the internal gas pre-charge pressure is now higher than the line pressure. The (stored) fluid now being displaced by the pulsation dampener maintains velocity downstream of the dampener thereby reducing, if not eliminating, any downstream pulsations.

Note: A pulsation dampener removes pulses only from the line downstream of the dampener-not upstream. That’s why it’s always recommended that discharge dampeners be installed as close to pump discharge nozzles as possible. In an application of a dampener for suction stabilization (reduction of acceleration head losses), it is the velocity gradient between the supply vessel and the suction nozzle that is minimized.

Let’s begin by defining the pump details required to properly size a pulsation dampener. We will use these values in a sample calculation to help clarify the process.

The result of the previous calculation is then divided by a constant. As noted previously, the constant is a function of pump configuration. We use a conservative 1.5 for simplex pumps, 2 for duplex pumps, and 7 for triplex pumps. Remember-if the fluid is compressible, then the constant may have to be adjusted downward.

Fluid volumes above mean are well within the range of these constants. The fluid pulse above mean flow from a simplex pump, for example, is about 60 percent. When we divide full stroke displacement by 1.5 the result is a conservative 67 percent. The divisor 7 that we use for triplex pumps allows for a nominal 14 percent fluid volume above mean. While 14 percent is far above the actual 4 percent produced by triplex pumps, the higher volume is an allowance for practical reasons, specifically size and nozzle limits. Otherwise, the result would be a very small dampener relative to pump size.

Ranges of (process) temperature and pressure must be considered in any sizing calculations for pulsation dampeners. Compensations must be made for temperature variations, which affect gas density, and dynamic variations in system pressure, since sizing is based on a set pre-charge pressure.

The objective is to select a dampener that is adequately sized to handle a range of operating pressures with a single pre-charge pressure. Remember that the gas pre-charge pressure should always be based on the minimum operating pressure as the pulsation dampener will have no effect when the system pressure is below the pre-charge pressure.

Changes in ambient temperature can also influence gas density, but they’re generally disregarded for the purposes of pulsation dampener sizing. It is usually sufficient to make seasonal adjustments to pre-charge pressures, if necessary. Temperature and pressure calculations are recommended to be done using absolute values (Kelvin for temperature and BarA or PSIA for pressure).

Some fluids are highly compressible, such as cryogenics, olefins, liquefied gases, anhydrous ammonia, etc. In these instances, the benefit of lower pulsations from multiple piston pumps may be somewhat compromised. Fluid compression occurs during the leading edge of the (eccentric) crank angle. Given sufficient pressure and a high enough compressibility factor, there may be little or no overlap of pulses at all-in which case, adjustments have to be made and pulsation dampeners with larger gas volumes should be selected.

By installing a properly-sized pulsation dampener, users can reduce or eliminate pipe shake, vibration and noise. The result is a continuous flow of product which is required in many metering, mixing and spraying applications. Reduced pressure pulsations minimize long-term damage to instrumentation and pump components while improving the accuracy of many flowmeters and increasing pump efficiency.

The start and stop action of positive displacement pumps rapidly accelerates and decelerates fluid in motion resulting in pulsations observed as pressure spikes. Pulsation dampeners absorb the energy of these pressure spikes by accumulating and then releasing process fluid when the pump is on its suction stroke. By keeping the fluid in motion, dampeners eliminate vibration and the pulsing, inconsistent flow caused by pulsation.

Water hammer (or hydraulic shock) occurs when fluid in motion is suddenly started, stopped or forced to change direction. Quick closing valves, rapid pump startup/shutdown, even changes in the pipe profile, can cause an abrupt change in fluid velocity producing violent and sometimes catastrophic water hammer. Surge suppressors act as shock absorbers by accumulating and releasing process fluid as needed to slow the rate of fluid velocity change to a level low enough to prevent water hammer.

This equipment plays an important role as an accessory to Yamada air-operated double diaphragm pumps. The pulsation dampener serves to reduce pulsation produced in operation and to assure stable discharge flow and pressure.

When pulsations occur with pump operation, it will result in the pressure in Chamber Bbeing greater than that in Chamber A. The diaphragm will act as an air cushion and automatically adjust to this pressure change and absorb the pulsations.

This operation will shift the center rod position upwards and allow more air in Chamber Athrough the air inlet, returning the diaphragm to a neutral position. If liquid pressure decreases, air pressure in Chamber Acauses the diaphragm to move downward, shifting shaft location and changing valve position, releasing excess air pressure in Chamber Awhich returns diaphragm to a neutral position. This action causes a reduction in surges and pulsation caused by a air operated double diaphragm pumps

Mud pump pulsation dampener is the mud pump discharge end main component, installs in the hydraulic end discharge pipe one end, plays the stable pressure and the pressure compensation function, the air bag work pressure is the mud pump work pressure 80%.Attention should be paid to the use of air bag, must be the first pressure relief.The mud pump of F500/F800 USES kb-45 air bag, and the mud pump of F1000/F1300/F1600 USES kb-75 air bag.The middle tie rod produced by our company is made of 35CrMo material, which has a smooth surface after chrome plating and fine grinding, greatly improving the wear resistance and corrosion resistance.

Proper installation and use of pulsation dampener can effectively reduce pressure fluctuations in the discharge system, thus achieving a more uniform fluid flow.In order to achieve a high service life of the air bag, always maintain the recommended ratio between the pump pressure and the air bag precharge pressure (generally not more than 2/3 of the pump discharge pressure, the maximum should not exceed 4.5mpa).

Warning: 1. Only compressed nitrogen or compressed air can be used when charging -- flammable and explosive gases such as oxygen or hydrogen cannot be used.2. In the maintenance of air bag, air bag pressure must be zero, the pump pressure must be zero.Cannot rely on the pressure gauge to judge, because the residual pressure is small, the pressure gauge can not be displayed, but this low pressure will also lead to accidents!

A mud pump is a reciprocating piston/plunger pump designed to circulate drilling fluid under high pressure (up to 7,500 psi (52,000 kPa)) down the drill string and back up the annulus. A duplex mud pump is an important part of the equipment used for oil well drilling.

Duplex mud pumps (two piston/plungers) have generally been replaced by the triplex pump, but are still common in developing countries. Two later developments are the hex pump with six vertical pistons/plungers, and various quintuplex’s with five horizontal piston/plungers. The advantages that Duplex mud pumps have over convention triplex pumps is a lower mud noise which assists with better Measurement while drilling and Logging while drilling decoding.

Use duplex mud pumps to make sure that the circulation of the mud being drilled or the supply of liquid reaches the bottom of the well from the mud cleaning system. Despite being older technology than the triplex mud pump, the duplex mud pumps can use either electricity or diesel, and maintenance is easy due to their binocular floating seals and safety valves.

A mud pump is composed of many parts including mud pump liner, mud pump piston, modules, hydraulic seat pullers, and other parts. Parts of a mud pump:housing itself

Duplex pumps are used to provide a secondary means of fuel transfer in the event of a failure of the primary pump. Each pump in a duplex set is sized to meet the full flow requirements of the system. Pump controllers can be set for any of the following common operating modes:Lead / Lag (Primary / Secondary): The lead (primary) pump is selected by the user and the lag (secondary pump operates when a failure of the primary pump is detected.

Alternating: Operates per Lead / Lag (Primary / Secondary) except that the operating pump and lead / lag status alternate on consecutive starts. A variation is to alternate the pumps based on the operating time (hour meter) of the lead pump.

This paper focuses on the operational experience that was gained during field test of the Hex Pump on a land rig in Jasper, Texas in October 2003. This field test showed that the pulsation frequency in the flow from the Hex Pump did not interfere with the MWD-measurements, providing a much cleaner signal to the directional driller. Also, the overall power consumption on the rig was reduced due to use of AC-motors.

A discharge dampener is designed and installed in the pipe to help absorb this pressure spike. The dampener consists of a vessel filled with gas or compressible material. When there are sudden changes in flow, the compressible material is able to compress and expand, similar to jumping onto your bed. The video below demonstrates the effects with and without a dampener.

By installing a pulsation dampener, the intensity of these spikes are reduced to controlled levels.A dampener should be sized and installed in all piping that may experience a harmful level of pressure spikes.

Pulsation dampeners can be purchased in a variety of shapes, sizes, and designs. It is important to size a pulsation dampener for a specific application. Incorrect sizing or incompatible materials may cause a danger to equipment, systems, and personnel.

Membrane Pulsation Dampener: A membrane-type dampener provides a solid separation between the pumping fluid and the compressible gas. The membrane resides within the dampener and allows for the pressure to be transferred to the gas, without any mixing of the gas into the fluid.

Bladder Pulsation Dampener: A bladder type dampener fully encloses the compressible gas within a bladder. This setup ensures there is no leakage of the gas into the pumping fluid. The pressure pulsations are transferred to the gas as the bladder expands and contracts.

Bellows Pulsation Dampener: A bellows-type dampener works the same way as a bladder type dampener. However, by using a bellows-type design, it can be made with other types of materials such as PTFE or Stainless Steel. This type of dampening system is used when pumping corrosive materials that may deteriorate more common materials.

Pressure Vessel Style: A pressure vessel dampener, sometimes referred to as a “zero maintenance” style dampener does not use any moving parts. They are only effective at very high pressures. Fluids, including water, do have some degree of compressibility. Pressure Vessel Style dampeners allow for the pressure of the fluid to be dissipated within the vessel by the small amount of compressibility within the pumping fluid. In very high-pressure applications, a pressure vessel style dampener may be the only type of dampener available. It is important to note that this style of dampener does not operate as effectively as other types of dampeners.

Flexible piping: Although it is not recommended, flexible piping or hose can act as a pulsation dampener in emergency situations. As the fluid flow changes, the flexible piping is able to “move” and allow a dampening effect on the fluid. Flexible piping still requires proper sizing to reduce pressure spikes. Improper usage may result in damage to equipment and endangerment of equipment operators.

Equipment that rapidly changes flow rates is recommended to have a pulsation dampener. Plunger pumps, for example, have a highly variable flow rate. The average flow rate of a plunger pump can be accurately predicted. However, each rotation of the crankshaft produces several changes in flow velocities.

When a plunger pump is running slowly, these pressure spikes can be ignored. In most cases, they will not produce enough of a spike to create damage. When the pump is running at full speed, this full cycle is taking place many times per second. The pressure spikes caused by these sudden changes will likely need a pulsation dampener.

The image above shows the visible pulsations created by a reciprocating quintuplex pump. Using flexible hoses on the inlet and outlet, the pressure fluctuations through the hose can easily be seen. Since steel piping is more rigid, it may be more difficult to visually see pressure vibrations before damage to piping and the surrounding systems takes place. It is important to correctly determine if a dampener is needed and to correctly install the required size before operating the pump system.

It is important to note that pressure pulsations are not a function of pressure. The operational pressures of a system have very little effect on the resulting pressure pulsations. Both suction and discharge sides of a reciprocating pump are susceptible to pulsations and resulting damage. Both the suction and discharge dampeners operate independently of each other. Proper sizing and installation of both suction and discharge dampeners are required for proper protection of pumping equipment and systems.