Hydraulic system maintenance framework

Lack of hydraulic system maintenance is the leading cause of component and system failure, yet most maintenance personnel do not understand proper maintenance techniques of a hydraulic system. The foundation to perform proper maintenance on a hydraulic system has three areas of concern: corrective, preventative and predictive.

Corrective Maintenance

It takes place following failure or damage, that is, it only occurs when there is an error in the system. This maintenance entails the following consequences:

  • Unplanned shutdowns
  • At production, it affects production lines
  • It means costs due to not budgeted repair and replacement
  • The time the system will be out of operation is not predictable

Preventative Maintenance (PM)

Preventive Maintenance of a hydraulic system is very basic and simple and if followed properly can eliminate most hydraulic component failure. Preventive Maintenance is also a discipline and must be followed consistently to obtain results.

Consider a PM program as being “performance oriented” rather than being “activity oriented.” Many organizations have good PM procedures but do not require maintenance personnel to follow them or hold them accountable for the proper execution of these procedures. To develop a good preventive maintenance program, follow these steps:

         1.  Identify the system operating condition.

  • Does the system operate 24 hours a day, 7 days a week?
  • Does the system operate at maximum flow and pressure 70% or better during operation?
  • Is the system located in a dirty or hot environment?
  • Identify the system operating condition.

2.  What requirements does the Equipment Manufacturer state for Preventive Maintenance on the hydraulic system?

3.  What requirements and operating parameters does the component manufacturer state concerning the hydraulic fluid ISO particulate?

4.  What requirements and operating parameters does the filter company state concerning their filters ability to meet this requirement?

5.  What equipment history is available to verify the above procedures for the hydraulic system?

As in all Preventive Maintenance Programs it’s a good practice to write procedures required for each PM task. Steps or procedures must be written for each task and they must be accurate and understandable by all maintenance personnel from entry level to master technicians. Preventive Maintenance procedures must be a part of the PM Job Plan which includes

  • Tools or special equipment required performing the task.
  • Parts or material required performing the procedure with store room number.
  • Safety precautions for this procedure.
  • Environmental concerns or potential hazards.

A list of Preventive Maintenance Task for a Hydraulic System could be:

Hydraulic system preventative maintenance task list

Preventive Maintenance is the core support that a hydraulic system must have to maximize component life and reduce system failure. Preventive Maintenance procedures that are properly written and followed will allow equipment to operate to its full potential and life cycle. Preventive Maintenance allows a maintenance department to control a hydraulic system rather than the system controlling the maintenance department. You must control a hydraulic system by telling it when you will perform maintenance on it and how much money you will spend on the maintenance for the system. Most companies allow the hydraulic system to control the maintenance on them, at a much higher cost.

Predictive Maintenance
Predictive maintenance consists of determining the real technical conditions (mechanical and electrical) of the equipment examined, while it is in full operation.

The cause of many breakdowns couldn’t have been prevented with routine maintenance, but could have been caught with a predictive model. In many cases, it doesn’t make sense at all to do PMs from both a cost AND a time perspective. Regarding the preventative maintenance model, there are 3 critical factors in preventative maintenance that you must consider:

  1. How bad is the worst-case scenario?
  2. What is the likelihood of a breakdown?
  3. How much will it cost?

So, how often should you PM? Should you do it every 6 months, every 8 months or maybe every 4 months? This is something that is a bit controversial and needs to be looked at from a cost perspective. At the end of the day, PMs can be expensive if you are over PMing something, but it can help prevent critical failures. However, you also need to consider the fact that even if you PM something, that doesn’t necessarily prevent all failures. You need to make sure you are PMing the right thing and the correct frequency.

So, which is the better, predictive maintenance or preventive maintenance?

At the end of the day, ideally you would like to move from reactive to predictive. You also need to be able to tell when something is close to breaking down, or when the efficiency of that machine goes down to a point where it makes more financial sense to replace a component.

 

 

 

 

 

 

Process Cooling Systems/Bearing Lube Cooling Systems/Turbine Lube Systems

Every industry has its unique challenges, but virtually all industries share the goals of increased machine uptime, reduced maintenance, improved safety, energy savings and lower total cost of ownership. Having a reliable machine lubrication system is vitally important. Bearing life is often much better when the bearing is kept clean and well lubricated. However, many applications make good maintenance difficult.

image of custom process cooling lubrication system

Process Cooling System
Process cooling systems provide cooling fluid to a process function.  The process starts with the reservoir; it provides some heat transfer, however the majority of cooling starts with heat exchangers. Heat exchangers remove heat from a system by transferring the heat to another media (water or air). Types of heat exchangers may include fan, shell & tube, plate or refrigerated and vary in cost and efficiency. Typically, multiple pumps are used to prevent a single failure from shutting down the system.

Bearing Lube / Cooling System

lubrication system featuring a bearing skid system

image of bearing lube skid

Bearing lubrication and cooling skids provide a source of cool clean oil to remove heat from bearings.  This extends the life of the system and prevents cost breakdowns.  Lube systems typically have the following:
                Reservoir
                Lube pump and optional backup lube pump
                Heat exchanger
                Filtration
                Gravity return ports
                Low and kill Level switches
                High and kill temperature switches
                Output pressure switch and gauge

Turbine Lube System

Turbines require bearings for support during operation. Each of these bearings are supplied with hydraulic oil for lubrication. Hydraulic Lubrication systems are crucial if turbines are to have a long and productive life. However, the oil itself needs to be kept at the right temperature for effective lubrication. EHA-manufactured hydraulic lubrication systems are designed to keep the oil at the right temperature. They typically feature the following components:

  • Lube Reservoir that contains the cooling oil for a turbine based pump.
  • Electrical emergency backup pump that provides pre-startup lube flow and backup flow in the case of a main turbine pump failure.
  • Low & high pressure switches Learn more about pressure switches for lubrication systems.
  • Dual Lube filtration with dirty filter indicators – Lean More
  • Pressure gauges before and after main filtration give a visual indication of the pressure
  • High Temperature switch and gauge
  • Water-to-Oil heat exchanger with water saving and temperature regulation valve
  • Lube temperature gauges before and after heat exchanger
  • Oil sample port - for easy lab sampling of oil 
  • Fluid Level indicator
  • Turbine Pressure regulator
  • Turbine suction and gravity return ports

Turbine lubrication maiuntenance system

image of turbine lubrication system

 

 

EHA - Advantages of using Accumulators in Hydraulic Systems

EHA Accumulator Rack
Energy storage
An essential function of accumulators is their ability to store energy. Particularly in cyclic or varying operations, accumulators discharge in times of high demand and recharge during periods of low demand. They are often used to supplement pump flow during peak demand. Without an accumulator, the pump and motor must be sized to handle peak power requirements even if maximum power is only required momentarily. Benefits include:
  • Smaller pump that recharges the system during periods of slack demand.
  • Smaller motor; a total system that demands less energy & heat and costs less.
Emergency backup
Accumulators can maintain a high-pressure charge almost indefinitely and serve as an emergency power source should a machine lose electric power or a pump fails. Benefits include:
  • Provides the necessary flow and pressure to retract a cylinder.
  • Close a valve.
  • Move a machine to a safe position until power is restored or the malfunction is corrected.
  • If a lubricant pump fails, the accumulator maintains pressure until the machine stops or a secondary pump restores flow.
Vibration and shock reduction.
Mounting a small accumulator near the outlet of the pump can absorb pulsations, minimize vibration and provide smoother operation. Also, adding an accumulator into the return line of machines can mitigate shock. Benefits include:
  • Cushioning "water" hammer effect
  • Prevent damage to sensitive components and extend component life and lower maintenance costs.
  • Reduce overall hydraulic system noise levels resulting in quieter machines.
Leakage & temperature compensation
An accumulator can maintain constant pressure even if fluid slowly leaks internally past piston seals or valve clearances and compensate for temperature-related pressure differences in a closed hydraulic system. Only when circuit pressure drops below preset limits does the pump fire up and recharge the accumulator.
 
Faster response
Bladder and diaphragm accumulators have virtually instantaneous response and can quickly supply fluid to valves and improve their performance. Accumulators can also immediately meet peak flow requirements.

EHA Fluid power Repairs

When the time comes and you experience cylinder failure, the decision must be made whether to buy new or repair. The benefits of repairing include:

  1. Shorter lead times
  2. Significant cost savings over new cylinders
  3. The ability to identify the cause of failure

Short Turnaround Time
EHA offers quick turnaround on cylinder repair as well as emergency repair service. We understand that breakdowns can occur at any time and when they do you are robbed of your valuable production time and profit. Our in-house machining capabilities are made up of multiple machining centers with experienced technicians They are qualified to rebuild your cylinder to a “better than new” condition. We have a fully equipped repair center with the necessary equipment for repairing cylinders of all sizes wide range of industries.

Save by Repair
Repairing a cylinder can save you approximately 40-50% the cost of new. Although a large portion of the savings comes as a direct result of using many of the existing parts in the repair process, this will not compromise the quality or performance of a repaired cylinder. We test every cylinder we repair. Our testing standards will assure you that your cylinder will be ready for immediate use when it leaves our facility.

Save With Investigative Information
Cylinders sent in for repair receive a thorough inspection at the start of the repair process. During this phase, our technicians check for any stress that may have been placed on the unit from excessive side loads, improper mounting, fluid contamination or defective seals. The information gathered during our inspection may help you adjust and correct issues with your related equipment to extend the life of your cylinders. Simply purchasing new cylinders may not address the specific issues that may lead to repeat failure of the new product.

 

sai logo image for hydraulic motors

Capabilities
Learn why SAI Hydraulic Motors has been the icon of "power through efficiency" for the past 50 years. Although this story began over 50 years ago, the reason SAI has remained one of the leading companies in the design and production-technology of crankshaft radial piston hydraulic motors has been their advancements in technology year after year. They have specialized in the ability to transform hydraulic power into mechanical power and help designers match overall efficiencies to the application requirements they are seeking. Let's break it down

Hydraulic System Efficiency
This requires hydraulic system designer to first match the motor, then the pump to a specific system performance expectation. Whether the requirement is to do something within a specific time frame, or in handling a given amount of load, the design of the entire system will change depending on the motor selected.
That  is why the motor selection comes first in the process; you start with the load requirement, then work back to the prime mover—the pump that will put the fluid power into the motor selected to deliver the performance goal.

Motor Type
Each motor type— gear, vane, in-line piston, bent-axis piston and radial piston—has a specific performance profile. So, knowing the application performance requirement and which motor type best meets the objective is the first step. Then it’s necessary to evaluate the design advantages of your motor options along with the degree of complexity you want for the overall system. In the end, it all goes back to the application’s performance expectations.

Motor Function
A hydraulic motor is a hydraulic actuator that, when properly connected into a hydraulic system, will produce a rotary actuation. This can be unidirectional or bidirectional depending on the system design. Motors are similar in design to pumps only where a pump takes a rotary actuation to move hydraulic fluid out of the unit, whereas a motor will take flow into itself and put out a rotary actuation.

Motor Selection Criteria

  1. The application of the hydraulic motor generally dictates the required horsepower and motor speed range, although the actual speed and torque required may sometimes be varied while maintaining the required horsepower.

  2. The type of motor selected depends on the required reliability, life, and performance. But where output speed must be reduced, the overall cost of the motor with speed reduction must be considered to optimize the overall drive installation costs.

  3. Once the type of the fluid is determined, the selection of actual size is based on the expected life and the economics of the overall installation of the machine.
    Caution: A fluid motor operating at less than rated capacity will provide a service life extension more than proportional to the reduction in operation below the rated capacity.

  4. Once the type of fluid is determined, the selection of actual size is based on the expected life and economics of the overall installation on the machine.
    Caution: A fluid motor operating at less than rated capacity will provide a service life extension more than proportional to the reduction in operation below rated capacity.


 SAI Hydraulic Motor Product Features

FEATURE: High Starting Torque
BENEFIT: The SAI motor has virtually the same starting torque and dynamic torque. This is due to the presence of the crankshaft roller bearing. With this, startup friction is greatly reduced.

FEATURE: High Volumetric Efficiency
BENEFIT: In all SAI motor parts under pressure, the sealing is provided by Teflon/elastomer seals. The seal can compensate for the normal wearing of parts, as well as the natural expansion of the parts under stress. This enables SAI motors to maintain excellent volumetric efficiency, even after several thousand working hours. This is especially useful in applications requiring precise speed control at very low speeds or good braking capability.

FEATURE: Contamination Resistance
BENEFIT: The SAI design can withstand very large contamination particles in the system, up to 40 µm. All dynamic parts, such as cylinders, pistons, distributors, and valves, are hardened to further enhance their performance and contamination resistance. Large clearances and seals between dynamic parts also adds to the contamination resistance.

FEATURE: Thermal Shock Resistance
BENEFIT: The large clearances also allow SAI motors to have excellent thermal shock resistance. The large clearances will accept thermal expansion, and will not cause the dynamic parts to come in contact with each other and prolong the life of the motor.

FEATURE: Cavitation Resistance
BENEFIT: The innovative SAI design allows the motor to run in partial or full cavitation. The roller bearing under the piston does not require lubrication, and the piston retaining rings ensure that the pistons remain in firm contact with the central roller bearing. These innovative features allow the SAI motor to operate in full cavitation. The traditional hydraulic motor design with hydrostatic balancing under the pistons require lubrication at all times. If there is no lubrication present, it will experience significant frictional damage.


Motors

sai Hydraulic Motors

The wide range range of SAI hydraulic motors including: Variable Displacement, Double Displacement and Fixed Displacement motors, characterized by radial pistons and crankshaft design.
Learn More
 


Shaft End Drive Units

Sai Shaft end drive units

SAI offers radial piston motors coupled to single or double stage planetary gearboxes with shaft ends.
Learn More
 


Complete Wheel Drives

sai complete wheel drive units

SAI offers complete wheel motors to be coupled with single or double stage planetary gearboxes and/or drum brakes; compact wheel drive units including planetary gearbox and/or integrated negative disc brakes.
Learn More


Brakes

sai hydraulic brakes

SAI offers shaft end brakes with negative disc.
Learn More
 



 

Rexroth Bosch HPU article

Rexroth Bosch Group White Paper Article on Designing  HPUs for Hydraulic Systems

Download full Whitepaper
8 minute read

Summary:

Applications

Applications for power units span the spectrum of fractional horsepower requirements to those incorporating drives using 100’s of horsepower. From left: Standard, pre-engineered power unit CytroPac; configurable GoPak power unit; typical custom power unit for industrial use; large, complex custom power unit. New capabilities and power unit designs provide many new options to machine and hydraulic system designers.

Environment

Environmental or other application-specific requirements, such as high altitude or required certifications, can drive one-of-a-kind solutions. Well-designed Hydraulic Power Units, whether large custom unit or a compact standard unit (including units built into a machine frame), consider all aspects of an application.

Complexity

Complexity in applications or specification may require complex control packages nearly the same size as the hydraulic power unit. A well designed and built power unit not only achieves functional criteria but can also be an attractive addition to the production floor. Full-featured, complex hydraulic power units should be designed toward functionality and robustness. A clean design must also consider periodic maintenance and service when needed, for example platforms to contain fluid spills, or easy access for replacement of filters.

7 Considerations

  1. Overall Power and Force Requirements
  2. The Operating Environment and Location
  3. Serviceability / Service Life
  4. Noise
  5. Energy Efficiency
  6. Cost
  7. So What About Industry 4.0 and “The Internet of Things?”

Conclusion

With all of the choices facing an engineer designing or selecting a power unit, the fact is this: Designing a power unit can be daunting. Not only must the successful designer develop a robust solution, one that will be capable of producing the “power” required over a long service-life, he or she must also consider plant-floor environments, safety, regulatory requirements, serviceability and maintenance, noise, energy efficiency, and sometimes even IoT-readiness. All of these considerations can influence the lifetime cost.

You’ll need to consider a partner who can provide support wherever your power unit might end up in operation and who is familiar with the safety requirements. IFP/EHA is your solution partner. Visit our previous blog post: Expertise in Hydraulic Power Units

 

 

Manufacturing, Sales & Service

IFP Group of Companies consists of Iowa Fluid Power, Electro-Hydraulic Automation (EHA) and Innovative Fluid Power. EHA, located in Cedar Rapids, Iowa is our world-class manufacturing facility specializing in hydraulics, pneumatics and motion control systems.

Hydraulic power units have been manufactured by EHA for the past 35 years for Industrial and Mobile market applications. We offer:
•    Standard base-pak pre-engineered fixed and pressure compensated power units.
•    Custom power units to thousands of horsepower.
•    Complete systems from fully automated electronic control systems

Through our many supplier affiliations at IFP we can provide the required components to build custom power units designed by EHA’s engineers using electric, gas or diesel prime movers; also experience with (natural & LP) gas applications.

Base-Pak Power Units

•    Standard Vertical Units from 3 to 30 Gallon.
•    Standard Horizontal Units from 10 to 100 Gallon.
•    Standard layouts provide quick delivery in single pieces or large quantities.
•    EHA's volume and manufacturing methods will give you the hydraulic flow and pressure that you need at a price
      you can afford.    


EHA manufactured power pak HPU

More Images

 

Custom Power Units

•    5 gallon to 5000 gallons.
•    Depending on customer preference, components from most of the different major fluid power manufacturers can be used.
•    Experienced engineering staff provides quick design turnaround and complete documentation.
•    From one unit to one hundred units, we can quickly deliver high quality, long life systems that will power your hydraulic
      machines for years to come.
    
      Complex HPU

More Images

 

Complete Systems

  • Hydrostatic and Open Loop hydraulic systems along with
    the electronics and the know-how to put together the system that you need.
  • Hydraulic systems for a single machine or "central" hydraulic systems to power your entire plant.
  • From thousands of horsepower to just a few, EHA can deliver the most efficient up-to-date system that your
    application demands.
  • EHA can provide electrical and electronic controls either to interface with your other in-plant systems or as a
    stand-alone machine.

    EHA manufactured cokple system HPU

Offshore Power Units

  • IFP provides an extensive range of hydraulic components from the world’s leading manufacturers.
  • EHA designs, manufactures and supplies customized equipment for the offshore industry.
  • Our knowledgeable team is available to answer your questions, whether technical or regarding product
    availability.
  • Optimal equipment performance in extreme working conditions, like the offshore industry, is our main
    consideration for all our solutions.

    EHA manufactured Offsore power unit

More Images

 

Prime Movers (Gas, Diesel or Electric Engines)

EHA Prime mover - gas powered EHA Prime Mover - Diesel Powered  Electric Motor Powered                        
  • EHA has engineers capable of specifying the HPU components and prime mover type based on torque, speed, and power requirements of the hydraulic power unit and system requirements.
  • Prime movers are fully load tested in one of our test cell .
  • The completed prime mover is then painted and prepared for shipment
    More Images

Whether you have very specific needs or you just looking for a high quality standard solution, we provide complete custom built Hydraulic Power Units (HPUs) for every industry, situation and requirement.


Power Unit line card

 

Safety guidelines for high-pressure hydraulics

white paper on safety guilelines working with uber high pressure hydraulic applications

Get the whitepaper: https://bit.ly/2J2Kka

Handling high-pressure hydraulics is serious business. It often involves working in confined spaces, lifting heavy machine parts or dealing with weather extremes in remote locations.To make engineers and maintenance personnel better aware of the issues surrounding high-pressure systems, CEJN, a quick-connect coupling manufacturer recently published a white paper, “Safety Guidelines for Ultra High-Pressure Hydraulic Applications.” It offers safety advice and practical tips for working with high-pressure hydraulic tools.

Here are a few examples.

Respect pressure
CEJN engineers stress that extreme pressure demands a high level of safety, as a leak or accidental disconnection could be catastrophic. Hose assemblies may fail abruptly and unexpectedly for any number of reasons, and oil shooting out at high pressure and velocity can cause serious personal injury and severe damage to equipment and products. Resulting environmental pollution can also demand costly cleanup.

Potential hazards include burst hose, whipping hose ends, oil-spray leakage, and coupling blow-off. It is critical to shut down machinery immediately if a leak occurs. And never, ever, try to locate the leak with your hands, or any other part of the body when a hose set is pressurized. Instead, use a suitable implement to inspect for hose damage.And if a fluid-injection injury occurs, treat it as a medical emergency and seek immediate treatment.

Don’t mix quick-connect couplings
Don’t mix quick-connect coupling halves from different manufacturers. And do not mix genuine products from a reputable manufacturer with so-called interchangeable parts from other suppliers. Unfortunately, this is especially important today when copycat couplings and hoses are circulating on the market.
The interface between coupling and nipple is crucial. The unique tolerances and dimensions engineered into high-quality parts are compromised by mixing brands. And even if the connection seems to fit, this does not mean that the connector will work optimally and safely. In the worst case, it could lead to accidental disconnection and high-pressure oil spray.

Watch Video: https://youtu.be/0TH0I4vjeis 
The danger when working with ultra high-pressure hydraulic applications


 

 

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