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It has been a reasonably warm autumn and winter so far, barring a couple of very cold days here and there. If you regularly monitor the temperature and check this against the peak operating temperature of your chosen hydraulic fluid and oil, you may not have had to make any adjustments so far, but it is inevitable that hydraulic equipment that is used or stored outdoors will require a fluid change at some point during the change of the seasons.
Of course, the oil and fluid are not the only parts of hydraulic equipment that need checking and maintaining during colder weather; seals and hoses are also liable to suffer from the effects of the cold, as well as the higher pressure inside from using fluid that may be too viscous at low temperatures. The increased resistance of hydraulic fluid that has become thicker leads to higher pressure inside the cylinders and hoses and if they are not designed to cope with a significant extra force, they can fail and leak.
When hydraulic fluid gets too cold it becomes more viscous, thereby decreasing the static pressure of the fluid. In extreme cases the fluid can actually congeal, rendering it useless. Reduced static pressure in the fluid causes air bubbles to form due to the suction on the pump inlet. These air bubbles then get compressed when the machinery is in use and burst, causing loud popping noises and vibrations which can damage the equipment, and depending on the application of that hydraulic machinery, could cause further problems. Excessive wear on parts can lead to mechanical failure, which is costly as repairs need to be made and work is often stopped as a result.
Lubricating oil is also subject to the same effects from the cold, and the extra wear caused by oil that has congealed can have a far reaching impact on business productivity, leading to mechanical failure when it is least expected. All machinery has an expected life span and maintenance schedule to keep it in working order and replace parts that get damaged, but if there is a significant amount of extra wear on parts due to inadequate lubrication, this will not have been accounted for in the schedule.
These problems are easily avoidable with a regular preventative maintenance schedule and a checklist for all staff tasked with using hydraulic equipment, so they know what to be aware of and what to report. When temperatures get lower there may be no suitable hydraulic fluid for some types of equipment, so heaters (if there are none built in) can be used as a last resort to warm the cylinders and reservoir, getting the fluid inside to the correct temperature for proper functioning.
If hydraulic fluids have not been changed to cope with any temperature drop they are exposed to this year, then now is the time to take action. Draining and flushing the system should be done every time the hydraulic fluid is changed, to ensure there are no adverse effects from mixing two different fluids (although some can safely be mixed). One good tip to bear in mind is to take the old fluid away before bringing the new one over, that way there can be no accidental re-filling of the old fluid back into the system.
Establishing a plan of preventative maintenance (if this has not already been done) is vital to keep hydraulic machinery functioning for as long as possible, reducing unexpected downtime and the associated costs. Although the extra responsibility and materials may require investment now, the benefits of no unplanned lapses in productivity far outweigh those costs.
We’ve always been a fan of predictive maintenance for hydraulic systems. It can save time, system damage, expense and downtime. If it’s not already embedded into your workshop processes, then we recommend that predictive maintenance is put right in there along with your inspection processes.
In this post we look at the categories that John Moubray uses in his Reliability Centred Maintenance II book to understand how predictive reasoning should be approached. This is then followed by an example of how it could be used to understand what’s happening with your hydraulic system by using your powers of reasoning.
Broken into these 6 major categories, these maintenance actions can save you expense, time and of course loss of productivity through downtime. What any engineer who works with hydraulic systems should focus on are:
1. Dynamic effects including the monitoring of vibration, pulses and acoustic emissions.
2. Particle effects including the monitoring of particles in the operating environments of the component – ie the condition of the lubricant.
3. Chemical effects: monitoring of the chemical elements in the components operating
4. Physical effects such as cracks, wear, fatigue
5. Effect of temperature
6. Effects of electrical
Although Moubray’s list does cover most of the hydraulic systems maintenance needs, it does not cover all and there are new techniques being discovered and devised continually that should be researched. The visual inspection is one of the most basic and necessary of all predictive maintenance techniques.
Putting this to the forefront, it’s important to look for the following during a hydraulic system inspection:
· Both the quantity and the quality of the hydraulic oil in the tank needs to be checked. The appearance should be bright and clear.
· Check for any leaks or weeps around the seals, connectors and component bodies.
· The surface condition of the tubes, pipes and hoses external.
· The cylinder rod-wiper seal condition needs to be checked.
· The cylinder rod surface. Look for scores, nicks and dents.
· The filter clogging indicator position.
· The readings of the operating pressure (test-points and gauges that have been permanently installed should be used)
· The operating temperature of oil (use either an installed thermocouple or a heat gun)
· Listen out for abnormal noises such as knocking and clicking
The success of predictive maintenance tasks depends on whether data is recorded and then how it is analysed, whether it’s collected through human senses or by using sophisticated measuring tools. It is then necessary to take actions that will either remedy the situation or avoid damage from occurring. The process for predictive maintenance is this:
· Data collection
· Analysis of data
· Predictive reasoning to ascertain possible future issues if maintenance is not addressed
As an example, you may prefer to perform an inspection of your system as part of your regular maintenance routine. You may discover that there is a noise that has increased in volume and that there is no longer a smooth cylinder movement with your actuator. There could be an interpretation of this even as there being issues with reliability and performance of the system up ahead including issues with lubricity. These are all issues to record and take note of for future analysis.
In addition it’s necessary to ensure that the interpretation of the data is in the right context. Perhaps your visual inspection reveals an issue with the filter being clogged. You may identify this from the clogging indicator. Although this would not normally be an issue, it is if the last time the filter element was cleaned or changed was just the day before. Although the data is the same, used through the filter of a different context, then your reasoning will be entirely different.
Summary. It’s important to identify issues in hydraulic systems so that action can be taken whilst the issue is still small. Predictive engineering offers this solution. It also makes it possible to refine your system so that you can avoid issues and enable your machine to have less downtime and expense. It’s truly worth getting into the routine of looking for issues early on.
Our engineers are focused on producing mobile hydraulic power packs. We provide insights into hydraulic system maintenance for those who have an interest. If you’re looking for a custom solution to your hydraulic system application needs, contact us today.
Hydraulics has been around for a very long time. But are you aware of how far it has actually come? You wouldn’t be alone if you responded with no. It is a very technical subject that can be quite difficult to understand, but in this article we want to tell you the story of hydraulics! We want to share with you who discovered hydraulics, what it was originally used for and how hydraulic power got to where it is today.
So why don’t we start at the beginning! Where does the word hydraulic come from?
The word hydraulic originates from the Greek word ‘Hydros’ which means water. Why water? Well, this is because water was the first liquid to be used in the hydraulic system. Today, hydraulics includes the physical behaviour of all liquids, not just water.
In this article we want to explain the ins and outs of hydraulic powerpacks. A vital piece of equipment that is used with so many machines we see every day.
In a nutshell, hydraulic powerpacks are self contained units that are used instead of a built in power supply for hydraulic machinery. Hydraulic power uses fluid to transmit power from one location to another in order to run a machine. It really is as simple as that.
So what do they look like?
In order to recognise and better understand hydraulic powerpacks, it is a good idea to get to know the key components. Hydraulic powerpacks come in many different shapes and sizes, some are very large and stationary whereas others are much smaller and more compact. In fact, some hydraulic powerpacks are so compact that they can easily be transported in a small van or even an estate car.
The only real way to identify hydraulic powerpacks is through its main components. No matter the size of the unit, all power packs will have the following; a hydraulic reservoir, regulators, a pump, motor, pressure supply lines and relief lines.
What do these components do?
It may be obvious to some but in this post we wanted to explain every component as simply as possible. So here goes.
First up is the hydraulic reservoir which quite simply holds the fluid. Reservoirs will come in different sizes.
Then we have the regulators. Regulators are vital as they control and maintain the amount of pressure that the hydraulic powerpack delivers.
Thirdly we have the pressure supply lines and relief lines. The supply line simply supplies fluid under pressure to the pump and the relief lines relieve pressure between the pump and the valves. The relief lines also control the direction of flow through the system.
Finally we have the pump and a motor. We will begin with the simpler component of the two, the motor. The motor is simply there to power the pump. Easy as that. Now the pump generally performs two actions. Firstly, it operates as a vacuum at the pump inlet and through atmospheric pressure forces fluid from the reservoir into the inlet line and then to the pump. It then delivers the fluid to the pump outlet and pumps it into the hydraulic system. We did warn you that the second part would be slightly more confusing.
So what is the function of hydraulic powerpacks?
Hydraulic powerpacks deliver power through a control valve which in turn runs the machine it is connected to. Hydraulic powerpacks come with a variety of valve connections. This means that you can power a variety of machines by using the appropriate valves.
Hydraulic powerpacks are relied upon by a range of different machines that use hydraulic power to do its work. If a machine is required to carry out heavy or systematic lifting then its likely it would need help from a hydraulic powerpack.
To make it easier for you to understand, we have included a list of trades that regularly rely on our powerpacks. On a building site you will see machines like bulldozers and excavators, which both need hydraulic powerpacks. But, it is not just on building sites that you will find these types of machines. Fishermen and mechanics both need hydraulic powerpacks too. If we did not have them then how would fishermen lift their nets or how would mechanics lift our cars?
When picking a hydraulic powerpack there are a variety of pumps and options to pick from and it is important to pick the right pack to meet your machines needs. It is also important to consider a pack that will help maximise productivity and minimise cost.
Many people will overlook the necessity of hydraulic powerpacks, but they really are vital to ensuring our society runs efficiently.
Do you need to maintain hydraulic powerpacks?
Yes you do and this is hugely important! Hydraulic powerpacks require regular maintenance to ensure they are working properly and safely and to help extend their life. Maintaining hydraulic powerpacks is relatively simple and includes checking the tubing, this can be for any noticeable problems such as dents or cracks. It is also vital to regularly change the hydraulic fluid and look at the reservoir to check for any corrosion or rust.
What hydraulic powerpacks do we provide?
Generally we provide four different types of hydraulic powerpacks. You can pick from a standard powerpack, a mini powerpack, a micro powerpack or a bespoke powerpack.
The standard hydraulic powerpack uses a standard range of modular components and is ideal for the most demanding industrial applications. The mini powerpack is ideal for applications requiring up to 5.5kW. The micro hydraulic powerpacks were originally produced for mobility applications, so are great for when space is limited. Finally, if none of these seem to fit your needs then we offer bespoke hydraulic powerpacks ensuring your application gets the hydraulic powerpack it requires.
Finally, who is the genius behind hydraulic powerpacks?
The man behind hydraulics was Laissez Pascal. A French mathematician, physicist and religious philosopher who lived in the mid seventeenth century. Pascal made observations about fluid and pressure which led to Pascal’s law. Pascal's law states that when there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container. Hydraulic powerpacks have been designed based on Pascal's law of physics, drawing their power from ratios of area and pressure.
So, interested in our Power Packs? Come on over to the main website and see what we can do for your Hydraulic Power Pack Needs .
Preventive Maintenance for Hydraulic Pump System
When it comes to preventative maintenance for hydraulic pumps, it’s essential to be aware of the critical part that the hydrostatic drive system plays. This is also known as the hydraulic pump system. This system comprises piping, valves and filters and is what controls the entire system.
Part of this system and what drives the machinery is the hydraulic motor or hydraulic cylinder. The hydraulic pump is the generator of power and the good running of this is what ensures the pressure is correct.
A hydraulic pump works in either a hydrostatic or hydrodynamic system. The former determines the pressure of stationary fluids, whilst the latter is what forces the liquid and will often result in the movement of the hydraulic machinery. The quality of the pump will depend upon what flow and pressure is required, in addition to the lifespan and its effectiveness.
When it comes to performing preventative maintenance of a hydraulic pump, it’s important to schedule this as a regular activity. Its success will depend upon a disciplined approach. It must also be related to performance so that any changes in performance are monitored and then action taken based on those results.
Considerations that you’ll need to keep in mind are:
· How often is the system operating? Is it full time or only periodically? Is the operating environment dirty and hot? You should also check the manual or instructions supplied by the manufacturer to understand what their recommended operating parameters and preventative maintenance are for the machinery.
· Check the filter and whether its predicted lifespan fits with your preventative maintenance plan. You should also check the history of the equipment and how often it has been serviced or undergone maintenance.
· As in all PM plans, there must be procedures written for each maintenance task. These actions must be written in a way that is very clear and not open to be misconstrued by maintenance personnel at all levels.
The routine maintenance of a hydraulic system may be the responsibility of a staff member without a background in the operation and repair of hydraulic machinery, who should follow a strict procedure with a checklist to ensure tasks are carried out in the right order and using the correct equipment. The replacement of hydraulic fluids is one area where extra care must be taken to use the right oil, as the average layperson may not distinguish between hydraulic oil and engine oil, or even fuel. Mistakes like this can be costly, and when equipment breaks down because of avoidable oversights it can undermine the integrity of the whole company; one silly mistake is usually a sign that other things are being overlooked.
Maintenance procedures should be written by an experienced engineer, possibly working with a technical writer, to produce a document that is easy to follow and contains all the relevant information. Procedures should be tested several times to ensure there is no room for interpretation of instructions – ambiguity in procedural documents can lead to poor practises. It is worth adding pictures to a checklist, to further enable staff to comply with the procedure. Some people take in information better when it is presented in a visual format than in words, and vice versa so by using both forms of communication the document will be comprehensible by non-hydraulically savvy staff.
There is one important ingredient in a checklist for hydraulic machinery maintenance and operation, and that is the “idiot test”. This refers to a step in a procedure or clause in a contract that clearly shows whether attention has been paid to detail. Some common examples are rock stars insisting on a bowl of sweets in their dressing room with a certain colour removed. This is not, as it appears on the face of it, brattish behaviour but a clever way of knowing whether or not standards have been followed throughout. If a simple task, like removing all the yellow sweets from a bowl, has not been done properly it is indicative of carelessness. The same concept applies for exams where the final instruction is to only answer one question – students who are not paying attention and are not interested in the bigger picture will answer every question before reading the last instruction.
If you want to ensure that your hydraulic equipment is being used and maintained to the correct standards you can incorporate an “idiot test”, like having to note down the volume of hydraulic fluid that has been added, or signing materials in and out of a book. These are easily checked by a supervisor without arousing suspicion, and failure to complete the “idiot test” lets you know to check over that person's work and offer extra training.
Of course, it is desirable to always have hydraulics savvy people undertaking maintenance and in some cases, the operation of equipment with a hydraulic motor, but this cannot always be achieved. Training courses in the operation of hydraulic equipment are essential for health and safety, but your ‘in house’ policies can always be tightened and tweaked to close any potential holes in procedure, and engineer out bad practise and common problems by refining your processes.
At this time of year even more so than ever!
With every type of mechanical and hydraulic equipment, it’s important to develop maintenance schedules to keep them in good repair. This is also the case with hydraulic pumps. By attending to regular maintenance tasks, it’s possible to not only secure safety for operators but it can also save on costly repairs.
Here’s what you can to do to deliver effective preventative maintenance for your hydraulic pumps.
Before you get started on any repairs, be sure to disconnect the pump from the power supply.
One of the most important and most regular of preventive maintenance tasks should be to regularly check the level of the hydraulic fluid. You may prefer to refer to your manual, but in many cases you should expect to see the oil level at ½ inch from the top of the level indicator. You will also need to check the reservoir oil level – keeping in mind that this will need to be drained, flushed and refilled with new high-grade oil on a regular basis.
A schedule for regular cleaning also needs to be devised as part of your hydraulic pump’s preventive maintenance work. To do this, first off you should seal the unused couplers through the use of thread protectors. Then check that all hose connections are clean of any grease, dirt and grime. The outer surface of the pump needs to be kept as clean as possible, as should all equipment that the pump is connected to.
When you drain, flush and refill the hydraulic oil reservoir, be sure to clean the exterior of the pump before you remove the pump interior.
You can do this by:
Removing all the screws that fastens the reservoir to the motor and pump assembly. Take care with the gasket and the filter so as not to cause any damage or movement. The pressure regulating valves are another area to be very careful around when you remove the assembly from the reservoir.
Now it’s time to clean the interior of the reservoir and fill it with flushing oil.
To make it easy to flush the reservoir, put the pump and motor assembly back into place on the reservoir. Now use just the screws that are in opposite positions on the corner of the housing. You should now run the pump. After several minutes it will have been flushed without you needing to attach the complete assembly. You can then detach the assembly again in order for you to drain and clean the reservoir. Finally, using a funnel with a clean filter, you can refill the reservoir with hydraulic fluid before rethreading each of the screws to keep everything firmly in place again.
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