what causes hydraulic pump whine supplier

Every hydraulic pump makes some noise. If all is well with a pump, then this noise stays more or less the same. However, if something goes wrong with the pump or its connected system parts, then you may start to hear sounds that you haven"t heard before.

The fluid that flows through your system needs to move at a smooth and even rate. The pump has to deliver the fluid at a specific flow for things to work.

If something prevents the fluid from achieving and maintaining its optimum flow, then your pump may start to make unusual noises. For example, you may hear a high-pitched whine coming from the pump. This can be a constant or intermittent sound.

If your pump whines constantly, then you may have a cavitation problem. Here, the pump can"t deliver its fluid at the right volume or rate. There isn"t enough fluid coming through the pump"s suction line.

In some cases, this is a sign that your pump"s motor is on the wrong setting. So, the pump itself is working at the wrong speed to create the right flow.

A hydraulic pump might get noisy if one of its parts or connections has a problem. A faulty or failing pressure control, bearing, valve, seal, or coupling can make a noise you haven"t heard before.

In some cases, you may hear vibrating clunks as your pump works if you have a problem with a connecting pipe. A loose seal or connector might allow the pipe to move. It then passes vibrations along to the pump itself.

While some noise problems are easy to fix, some are a sign that your pump is close to the end of its working life. Sometimes, this is due to natural wear, usage, and age. However, in some cases, minor problems cause more widespread damage if you don"t fix them quickly.

For example, if you"ve had cavitation problems for a while, then your system may not have been getting the lubrication it needs; it may have overheated regularly. Even if you fix the cavitation issue, you may be left with a damaged pump that needs a more significant repair, rebuild, or replacement.

So, while new sounds or an increase in operating noise don"t necessarily mean that you have a serious pump problem, you should investigate any unusual noise. Typically, this is a sign that something isn"t working right.

A minor problem in your system could go on to cause significant damage. For an expert diagnosis, contact Quad Fluid Dynamics, Inc. Ourhydraulic pump repair and rebuild servicewill get your pump running smoothly and efficiently again.

Pump cavitation is first and foremost caused by insufficient flow. This happens when the volume of fluid being supplied doesn’t meet the demands of the hydraulic circuit, and the pressure at the suction end of the pump isn’t sufficient. This leads to the absolute pressure falling below the vapor pressure of the liquid, which leads to air bubbles being formed. These tiny bubbles implode as they pass through the system, creating shockwaves and causing pump vibrations.

The process of these bubbles forming and collapsing is done with a great deal of force, and leads to eventual metal erosion inside the pump. The mechanical damage caused by cavitation can have irreversible impacts on system components and may possibly lead to complete failure. Cavitation happens only on the suction side of the pump, and may be caused by a series of different malfunctions, including:

Cavitation is typically characterised as a high-pitched whining or screeching sound, and in some extreme cases, can present itself as a loud rattling sound. Whilst these hydraulic pump whine noises are generally the most obvious telltale signs of cavitation, other symptoms to look out for also include:

By design, hydraulic pumps contain a miniscule amount of air which allows space for the hydraulic fluid to heat up and expand. However, too much air in the pump can cause serious issues – this is known as aeration.

Aeration in a hydraulic pump occurs when there is an air leak in the suction line. When outside air enters the pump through a damaged connector, loose pump seal, pipe fitting, or any other damage, it gets drawn into the pump’s hydraulic fluid supply. This unwanted air quickly gets dissolved into the hydraulic fluid and leads to contamination.

Contaminated hydraulic fluid can have serious implications for the system, as the excess air means that it cannot conduct heat as efficiently and can cause the fluid to foam. This can lead to overheating and in some cases, a substantial decrease in power. Aeration may happen on both sides of the pump, and has several causes including:

Similar to cavitation, aeration is usually indicated by a sudden change in noise, which can sometimes make it difficult to differentiate between the two causes However, aeration tends to produce a more erratic low-pitched ‘rumbling’ or ‘rattling sound, as opposed to the more consistent whining noise of cavitation.

Excessive or erratic hydraulic pump noise is a symptom of malfunction that could cause damage or accelerated wear if not addressed quickly and correctly. While it’s never nice to hear strange noises emitted from your pump, different forms of noise, which are related to different faults can provide valuable clues that can help you to diagnose your problem and get it fixed before it turns into something major.

So it pays to know what different pump noises mean and with practice you can quickly distinguish between the normal operating sounds and signs that something is wrong. In this article, we’ll talk about what causes some of these sounds, so you can identify them.

A constant hissing sound is indicative of a relief valve that is set too low or is stuck open and is continually releasing pressure. An erratic whistling sound is a symptom that a relief valve is set incorrectly or is damaged. It is common for pump settings to be changed carelessly or inadvertently - sometimes to overcome other issues with the hydraulic system - sometimes due to a lack of understanding of the correct operating conditions, so include this in your regular checks. In addition to noise problems, relief valve damage can be accompanied by slamming of actuators, stalls and excessive heat generation.

Noise issues are just one symptom that gives you a clue when things go wrong with your hydraulic pump. There are several other issues to know and understand, which could help you to identify pump problems quicker. Which means you can sort them out sooner - potentially saving big money down the road. These include heat problems, pressure problems and flow problems.

Longer cycle times are often the first indication that there is something wrong with a hydraulic system. Decreased speed of hydraulic actuators (such as cylinders) points to decreased flow through the system.

Decreased flow can be caused by either external or internal leaks. External leakage can often be spotted very easily. Look for leaking/busted hydraulic hose, hydraulic fluid around connectors or under components.

See the related blogs on preventive maintenance of hydraulic hoses and knowing when to replace a hydraulic hose. Another related blog, “What is Causing Your Hydraulic System to Leak” has a free download of our Port End Assembly Guide, which can educate your maintenance personnel on preventing connector leaks in the first place.

Internal leaks (such as high-pressure fluid passing around the cylinder piston, or incorrectly set relief valve pressure) are more challenging to identify. One way to identify an internal leak is by detecting elevated temperature of a failing component. A leak generates heat. Higher temperature results in decreased viscosity of the hydraulic fluid. Decreased viscosity of the fluid further increases leakage, leading to additional increases in temperature… You get the picture of how the situation escalates.

In some cases, temperature measurement is not conclusive. If an internal leak cannot be detected by locating a component generating abnormal heat, use a hydraulic flow meter.

Knocking, loud whining, or screeching often indicates aeration or cavitation. Aeration means air inclusion in the hydraulic fluid, cavitation is the presence of vaporized hydraulic fluid in the system.

Banging or knocking noises can indicate that air is included in the hydraulic fluid. Other symptoms of air inclusion are foaming of the fluid, and erratic actuator movements.

Air in the system accelerates breakdown of the hydraulic fluid and decreases hydraulic fluid’s lubricating properties. Both conditions lead to increased wear of the system’s components, through increased friction, overheating, and burning of seals.

Air usually enters the system through the pump intake. Check the fluid level and a condition of the suction hose. If the hose is old or shows any warning signs, replace it. See related blogs on knowing when to replace a hydraulic hose, scheduled hydraulic hose replacement, and preventive maintenance of hydraulic hoses for more information on the subject.

Cavitation results from demand for hydraulic fluid not being met. Typically (but not exclusively), this happens at the pump. The insufficient flow causes the absolute pressure in the affected part of the circuit to fall below the vapor pressure of the hydraulic fluid, which in turns causes formation of vapor cavities within the fluid. When the vapor cavities are compressed, they implode and produce a knocking noise.

Excessive temperature of hydraulic fluid (generally above 180°F), reduces its working life and damages seals in the system. In addition, viscosity of hydraulic fluid decreases with increasing temperature, which in turn results in inadequate lubrication and increased wear of the system"s components.

There are two general causes for increased hydraulic fluid temperature: either a component produces more heat than it should, or the heat dissipation capacity of the system is reduced/inadequate.

Regularly check the hydraulic oil level and viscosity. Check the heat exchanger for any obstructions in both coolant lines and hydraulic fluid lines. Make sure that the heat exchanger has adequate space around it.

To properly analyze and/or troubleshoot your hydraulic system, you will need some tools. At minimum, you need to be able to measure pressure, temperature, and flow at different parts of your circuit. The more complex your hydraulic system, the more sophisticated meters you will need to get the job done.

Parker SensoControl family of diagnostic meters offers four different diagnostic solutions to address the needs of maintenance personnel, based on the complexity of their hydraulic circuits.

Hey everyone. We"ve recently started hearing a noise that sounds like it"s coming from our hydraulic pump. It usually only makes this sound at certain rpms and when the volume control is adjusted higher it seems to increase the noise. We have a 2014 Concord 40meter with less than 600 hrs

what kind of noise do you hear? when it appears, is it a constant noise, and when you adjust the volume, does it go away? i suspect, that there is a bearing inside the pump, that is not 100% anymore, possibly unbalanced, and at certain rpms/settings the noise intensifies, to the point that you can hear it.

Thank you for your reply. The noise is basically a higher pitched whining noise. It only makes the sound when rpms are turned up. If we are pumping at lower rpms and we turn volume up, it will also make the noise. You are actually the second person to suggest a bearing going out.

Try engaging the PTO in a gear Lower than normal. If it pumps in 7th gear, put the PTO in 6th gear. If the noise is the same, Exactly the same, it"s likely not a bearing issue. If the noise is still present but at a noticeably Lower pitch, then it"s possibly a bearing.

The second leading cause of hydraulic pump failure, behind contamination, is cavitation. Cavitation is a condition that can also potentially damage or compromise your hydraulic system. For this reason, understanding cavitation, its symptoms, and methods of prevention are critical to the efficiency and overall health of not just your hydraulic pump, but your hydraulic system as a whole.

The product of excessive vacuum conditions created at the hydraulic pump’s inlet (supply side), cavitation is the formation, and collapse of vapors within a hydraulic pump. High vacuum creates vapor bubbles within the oil, which are carried to the discharge (pressure) side. These bubbles then collapse, thus cavitation.

This type of hydraulic pump failure is caused by poor plumbing, flow restrictions, or high oil viscosity; however, the leading cause of cavitation is poor plumbing. Poor plumbing is the result of incorrectly sized hose or fittings and or an indirect (not straight or vertical) path from the pump to the reservoir. Flow restrictions, for example, include buildup in the strainer or the use of an incorrect length of hose or a valve that is not fully open. Lastly, high oil viscosity—or oil that is too viscous—will not flow easily to the pump. Oil viscosity must be appropriate for the climate and application in which the hydraulic pump is being used.

The greatest damage caused by cavitation results from the excessive heat generated as the vapor bubbles collapse under the pressure at the pump outlet or discharge side. On the discharge side, these vapor bubbles collapse as the pressure causes the gases to return to a liquid state. The collapses of these bubbles result in violent implosions, drawing surrounding material, or debris, into the collapse. The temperature at the point of implosion can exceed 5,000° F. Keep in mind that in order for these implosions to happen, there must be high vacuum at the inlet and high pressure at the outlet.

Cavitation is usually recognized by sound. The pump will either produce a “whining” sound (more mild conditions) or a “rattling” sound (from intense implosions) that can sound like marbles in a can. If you’re hearing either of these sounds, you first need to determine the source. Just because you hear one of these two sounds doesn’t guarantee that your hydraulic pump is the culprit.

To isolate the pump from the power take-off (PTO) to confirm the source, remove the bolts that connect the two components and detach the pump from the PTO. Next, run the PTO with no pump and see if the sound is still present. If not, it is safe to assume your hydraulic pump is the problem.

Another sign you may be experiencing cavitation is physical evidence. As part of your general maintenance, you should be inspecting and replacing the hydraulic oil filter"s elements at regular intervals based on the duty cycle of the application and how often it is used. If at any time during the inspection and replacement of these elements you find metallic debris, it could be a sign that you’re experiencing cavitation in the pump.

The easiest way to determine the health of your complete hydraulic circuit is to check the filter. Every system should have a hydraulic oil filter somewhere in-line. Return line filters should be plumbed in the, you guessed it, return line from the actuator back to tank—as close to the tank as possible. As mentioned earlier, this filter will have elements that should be replaced at regular intervals. If you find metallic debris, your pump could be experiencing cavitation. You’ll then need to flush the entire system and remove the pump for inspection.

Conversely, if you’ve already determined the pump to be damaged, you should remove the filter element, cut it open, and inspect it. If you find a lot of metal, you’ll need to flush the entire system and keep an eye on the other components that may be compromised as a result.

Once cavitation has been detected within the hydraulic pump, you’ll need to determine the exact cause of cavitation. If you don’t, cavitation can result in pump failure and compromise additional components—potentially costing you your system.

Since the pump is fed via gravity and atmospheric pressure, the path between the reservoir and the pump should be as vertical and straight as possible. This means that the pump should be located as close to the reservoir as is practical with no 90-degree fittings or unnecessary bends in the supply hose. Whenever possible, be sure to locate the reservoir above the pump and have the largest supply ports in the reservoir as well. And don"t forget, ensure the reservoir has a proper breather cap or is pressurized (3–5 PSI), either with an air system or pressure breather cap.

Be sure the supply line shut-off valve (if equipped) is fully open with no restrictions. This should be a “full-flow” ball valve with the same inside diameter (i.d.) as the supply hose. If feasible, locate a vacuum gauge that can be T’d into the supply line and plumb it at the pump inlet port. Activate the PTO and operate a hydraulic function while monitoring the gauge. If it reads >5 in. Hg, shut it off, and resume your inspection.

A hose with an inner bladder vulcanized to a heavy spiral is designed to withstand vacuum conditions as opposed to outward pressure. The layline will also denote the size of the hose (i.d.). You can use Muncie Power’s PPC-1 hydraulic hose calculator to determine the optimal diameter for your particular application based on operating flows.

Another consideration, in regards to the inlet plumbing, is laminar flow. To reduce noise and turbulence at the pump inlet, the length of the supply hose should be at least 10 times its diameter. This means that any type of shut-off valve or strainer at the reservoir should be at least 10 diameters from the pump inlet. A flared, flange-style fitting at the pump inlet can also reduce pump noise by at least 50 percent compared to a SAE, JIC, or NPT fitting.

Selecting the proper viscosity of hydraulic fluid for your climate and application is also critical. Oil that is too viscous will not flow as easily to the pump. Consult your local hydraulic oil supplier for help selecting the optimal fluid viscosity.

By maintaining a regular maintenance schedule, remaining vigilant for any signs or symptoms, and taking preventative measures, the good news is that you should be able to prevent cavitation and experience efficient operation for the duration of your pump’s lifespan.

Poor plumbing is the leading cause of cavitation and can be prevented by selecting a properly sized hose, choosing the appropriate fittings, ensuring the most direct, straight routing from the pump to the reservoir, etc.

There’snothing quite like the high-pitched racket emitting from a hydraulic power unit. The combination of noises originates primarily at the hydraulic pump, but secondary harmonics and reverberations contribute to a cacophony, unlike any other machine noise. The telltale hydraulic whine is the bane of machine operators forced to mentally block the press/shear/extruder noise, raising their neck hair.

The hydraulic power unit noise problem isn’t lost on engineers and designers. As a result, manufacturers have designed components to be inherently smoother and quieter. Hydraulic designers may also select components less likely to contribute to the raucous sound. At the same time, technicians have options to ensure that as little of the vibrations as possible translate into annoying and potentially hazardous noise.

Pressure from the pump means turbulenceMuch of the attention applied to noise and vibration reduction is rightfully aimed squarely at the hydraulic pump. Most hydraulic pumps transform incoming mechanical energy into hydraulic energy discretely. Rather than feed a continuous stream of hydraulic fluid into the circuit, a pump sends individual packets of pressurized fluid to the outlet. Each discrete bundle of compressed hydraulic fluid blasts forth into the pressure line with a tiny wave of pressure.

No pump perfectly transmits pressure without bumps, corners, or turbulence, and each impedance encourages vibration and noise. More often than not, lens plates, gears, vanes, ports, and pistons all contain sharp edges, abrupt turns, or choked flow paths. The movement of fluid through a pump is far from laminar. Even if every metal pump component were chamfered, bevelled and honed, the resulting reduction in noise generation would likely be offset by the same reduction in efficiency.

From a design and installation perspective, the manufacturer holds responsibility for effort and ingenuity that must result in quieting solutions. In addition, a manufacturer must balance the varied demand asked of their pumps, which requires efficient operation across various pressure and flow outputs. A pump may be designed to limit pressure pulsations at 1,800 rpm and 3,000 psi but could do so poorly when run at 3,450 rpm and 1,000 psi, for example.

The pump pulsation is the primary NVH (Noise, Vibration & Harshness) driver. Each of those hydraulic energy bundles discharged from a pumping element (like a piston) or chamber (like vanes and gears) emits a pulse, and the frequency of those pulses dictates the timbre of the hydraulic noise. The frequency is a product of the prime mover rpm and the number of elements or chambers. A 9-piston pump running at 1,750 rpm results in 1,5750 pressure signals per minute. In acoustic terms, the pump’s fundamental frequency is 262.5 Hz (15,750 divided by 60 seconds in a minute) while also emitting high amplitude harmonics at 525 and 787.5 Hz.

By the same token, a pump may produce harmonics anywhere within the audible spectrum between 20 Hz and 20,000 Hz (or 11,500 Hz as tested for this author’s “old man ears” *see sidebar). Of course, we all know these harmonics combine to make annoying sounds, especially the harmonics falling between 1,000 & 5,000 Hz, where people’s hearing is most sensitive.

Looking at other sources of noise and vibrationMoreover, it’s essential to understand the rest of the hydraulic power unit’s contribution to amplifying noise. The prime mover and pump contribute most of the fundamental frequencies, but anything and everything attached to the power unit transmits and emits vibration and sound. An acoustic engineer could spend many times the cost of the power unit calculating and estimating how loud the power unit might be and at what frequencies. But sometimes, the particular sound and harmonics are unpredictable.

Let’s take the reservoir, for example. Its combination of welded plates, cut-outs, holes, and accessories sometimes augment the fundamental and harmonic frequencies emitted by the pump. Every physical body has a natural harmonic frequency, and sometimes those harmonics can overlap. When sound frequencies overlap with peaks atop peaks (Figure 1), the sound pressure level increases. Depending on the mass, size, shape, and elasticity of the object adding the resonance, the increase could range from barely audible to ear-splitting. When the dice fall against your favor, the reservoir may literally ring with resonance.

As much as possible should be done to isolate the pump from any possible harmonic contributor. The most obvious point of shared vibration is where the pump/motor attaches to the reservoir. Two traditional methods are common — vertical (in-tank) and horizontal (tank top). The L-Shape and elevated tank make great choices, but the prior two choices far outnumber the latter.

With vertical motor power units, the pump resides below the oil level through a large hole in the top surface where the bell housing attaches using (typically) four bolts in its flange. Any vibration in the pump or motor transmits directly to that top plate and any other metal welded, clamped, or bolted to the tank. The horizontally mounted pump uses a C-Face motor that directly couples the pump using a similar bell housing. However, these units employ foot mounting via the motor, but the opportunity still exists for the pump’s vibrations to transmit through the bell housing and motor to the tank top surface as well.

If you’ve designed or fabricated a hydraulic power unit, you know we don’t just weld or bolt the pump/motor group together and hope for the best. The damping of sound and vibration starts at the connection between the pump and motor. The drive couplers transfer the power from the motor to the pump and use a rubber insert tightly sandwiched between the couplers to reduce the vibration transfer from one to the other. The couplers and insert also help with shaft misalignment.

Any time you introduce elasticity to an interface, you reduce the natural frequency of the assembly. Elastomers (or actual springs) should be chosen with a natural frequency at least half that of the pump’s rotational frequency. For example, your 1,800 rpm motor’s 30 Hz frequency would best due with isolators offering 10 Hz or less. This theory applies not only to the coupler insert but the anti-vibration mounting feet (Figure 2) used to attach a horizontal pump/motor to the reservoir.

The individual mounting feet seen in Figure 2 are less prevalent in applications where the motor fully supports the pump via the bell housing. However, when foot-mounted pumps sit directly on the reservoir top and the motor is asked only to support its own weight, these act as a vibration buffer. For bell housing-mounted pumps, the solution is two-fold. First, rubber gaskets mounted between the motor C-Face and the bell housing provide a barrier for vibration and sound (and also work well in vertical pump power units). The motor is best mounted using vibration-damping bars as an additional isolation layer. Consisting of a thick rubber pad sandwiched between two steel bars, the damping bars allow the technician to bolt the pump to the top bar while welding the bottom directly to the tank.

Taking plumbing into considerationOf course, other components transmit sound and vibration besides the pump/motor group. You’d be surprised at how much sound energy transmits through plumbing, such as tubes and hoses. The steel of the tube or hose reinforcement vibrates readily in tune with specific harmonics, although the effect is mitigated by long lengths of plumbing, which have a lower natural frequency.

Figure 3. Having all hydraulic hose or steel tube in a high-pressure hydraulic system is a recipe for noise. Using a combination of steel tube with hose reduces cyclical radial expansion over a long hose but also isolates the tube from direct machine vibrations.

Sound emits not only from vibrating components but also through the hydraulic fluid itself. In fact, liquids transmit sound energy more efficiently than does air, so anywhere a conduit filled with oil goes, so too does pump noise. The creative use of pressure line accessories helps to dampen and absorb noise as it leaves the pump. Hydropneumatic accumulators charged to around 1/3 operating pressure and teed into the pressure line provide a damper to absorb pressure waves, thereby reducing noise energy.

Noise may come from unexpected sources, as well. One application took our team days to discover and remedy the solution. It was a standard hydraulic power unit with a vertical pump motor mount attached to an 80-gal reservoir. Mounted atop was a kidney loop circuit for filtration and cooling, which included a liquid-to-air cooler. We narrowed the noise down to the cooler, which was constructed using bent sheet metal to shroud the heat exchanger. Our choice of pump, along with steel tubing, created a harmonic resonance of the sheet metal.

Our fix was ad hoc, and through elimination, we changed to a different pump displacement, replaced the tube with hose, and then added two 90° elbows in series at the cooler inlet port. What previously gave the office workers headaches from the piercing noise morphed into your standard hydraulic whine. Even when all noise-reduction measures are heeded, sometimes the stars align to make a cacophony unintentionally with no way to predict the result.

Well how about the oil you used? Cold weather spells viscosity change and if the new oil has a higher viscosity at the colder temperatures, the pump could be sucking on it but it"s not moving as fast as the pump would like so it creates a minute vacuum on the suction side which causes bubbles and the bubbles are what"s making the noise.

Once the fluid warms viscosity drops, flow increases and the bubbles disappear. Or, as stated, it"s a pressure relief valve jabbering at you and the thicker fluid causes it to over/under compensate, the lag causing the pressure differential and the noise. I"ll bet on it being the pump especially since you heard it making the racket.

Tractor mfgrs make tractors, not fluids, tires, gens, fan belts, batteries, on and on. They either generate a spec and find someone to build what they want under their badge, or shop the market for something available that suits their design requirements and may go to them for a paint/badge modification.

Hydraulic systems can be extremely useful in a lot of machine solutions, but they can also be extremely loud. Any industrial location with active machines will make some noise, but when the noise rises to a certain level, it can be a problem. Systems that are too loud can cause headaches, hearing loss and elevated stress — and the noise may make it difficult for your workers to focus on what they are doing.

For this reason and others, it can be very useful to your operation for you to know how to reduce hydraulic system noise. While each situation is a little bit different, here are some tips and guidelines for noise control in hydraulic systems.

While it is impossible to completely eliminate hydraulic system noise, quality noise control in hydraulic systems is definitely possible. It starts with understanding the source of hydraulic system noise. Once you know where the noise is coming from, you are in a much better position to control it. While hydraulic noise originates from the pump, the power unit is the greatest contributor to hydraulic system noise.

Pressure fluctuations and vibrations of the various components of the system can amplify hydraulic noise as well. Each part of the hydraulic system has a potential noise control solution.

You’ve probably noticed that everything with an electric motor makes some noise. In many cases, very loud noise. A hydraulic system is no different. The movement of the fan, the vibrating of the bearings and the rotor and stator assembly all translate into what can be some very grating noise.

Hydraulic motors and other actuators can be some of the noisiest components of the system. A few tricks for keeping the hydraulic motor quiet include using very long tubing with a hose assembly at both ends and using a mesh screen set 30 degrees form horizontal.

Bearings, pistons, gears and the many other components of the pump can all combine to make a lot of noise, especially when you join the pump to the loud electric motor. Submerging the entire motor-pump assembly in oil or some other liquid can create a barrier that significantly dampens the sound of the system. You can also make the pump quieter by running it at a lower speed or using multiple small pumps instead of one or two large pumps.

One of the most important tools for reducing hydraulic system noise is the use of vibration-dampening mounts. You can mount the motor-pump assembly to a subframe with vibration-dampening mounts and you can mount the subframe to the power unit with vibration dampening mounts. Other industrial soundproofing materials wrapped around your hydraulic system can also be useful in reducing unwanted noise.

If the manufacturer is of no help, you can always contact a local engineering lab. These labs often have hydraulic experts that are highly knowledgeable and may relish the chance to take a look at your system and come up with ways to make it quieter and more efficient.

It’s also possible that your hydraulic system is making so much noise because it is in need of repair. If you suspect this is the case, either because you are having other problems with the system or you are seeing other possible symptoms of a problem like heavy shaking or sounds that you have not heard before, it can pay to have a professional take a look.

You can call Global Electronic Services anytime to have a certified professional inspect your system and perform a fast, efficient repair if necessary. For an estimate on hydraulics repair, call 877-249-1701 or contact Global Electronic Services online today.

Noise is undesirable because it can cause additional load on hydraulic components leading to premature failure, additional system cost, operator fatigue and potential hearing loss. The U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) states that exposure to 85 dB(A) of noise for more than eight hours per day can result in permanent noise-induced hearing loss (NIHL)1.

Noise is known to cause many issues with components in hydraulic systems but in particular steel tube assemblies are known to be very susceptible to vibration failure.

Vibration can travel through the system via the fluid and/or metal components transmitting to all parts of the equipment. Noise travels easily through the metal components such as pumps, valves, cylinders, steel tubes and elbow fittings but can also travel through the steel wire reinforcement in the hose.

A quick and easy solution that some designers have discovered to eliminate noise in power steering systems, hydrostatic pumps, pump outlets, motor inlet/outlet and PTOs is to utilize thermoplastic fiber reinforced hose. This hose is constructed using a variety of smooth bore polymer inner cores for a high degree of chemical compatibility, high strength fibers, and a polymer jacket. Fiber braided thermoplastic hose is available in pressure ratings from 500 psi to 7500 psi.

Parker"s Parflex Division is contacted at least once a month by companies looking to bring the noise down below audible noise level (vibration). Through years of studying noise and its effects on hydraulic systems, as well as, working closely with our customers to reduce application-specific noise, Parflex has developed an extensive line of thermoplastic hoses with a high degree of dampening effects.

Parflex 510D, 518D, 520Nand 53DM are most suited for reducing noise and have a working pressure range of 1500 to 5000 psi at a 4:1 design factor. Hose selection tools and application engineering expertise are available through Parflex for your equipment hydraulic design needs.

A steel mill reported a strange noise at one of several hydraulic motors driving a roll on a rolling mill. The hydraulic power supply was in the basement of the steel mill.

The hydraulic motors on all the driven rolls were bent-axis piston motors with a manifold block mounted on the motor containing two cross post reliefs. The control valves were mounted on valve stands in the basement along with the main pumps. The noise was only on one unit at the roll.

Maintenance told me that one hydraulic motor was “gurgling” on start up. After a few minutes it would quite down and seem fine. However, each time the mill was stopped for more than a few minutes, it would happen again. They replaced the motor but still had the same problem. One mechanic thought it might be caused by a new hose they had installed before the noise problem, but it looked like a good assembly. There was no sign of oil leaking from any plumbing connections to the motor, which could allow air to enter when the unit was shut down.