Power Take-Offs (PTOs) are designed to pick up engine power through rotation and transfer the power to another piece of equipment. For this to work, a piece of equipment can be mounted to the PTO or it can be connected by a driveshaft. The process begins with the PTO input gears meshing with one of the gears in a vehicle’s transmission starting the rotation. This rotation created from the engine drives the transmission and results in turning the PTO gear and rotating the PTO output shaft. Input gears must mesh properly with the transmission’s PTO drive gear for the PTO to work. But there are a series of gears that must be considered to determine the final output ratio of the PTO.Gear measurement terms
When analyzing the gears, a measurement term to be familiar with is gear pitch. Gear pitch is the measure of the size of the teeth and is determined by the number of teeth in a given area. To calculate the gear pitch, you would divide the number of teeth by the pitch diameter of the gear. Knowing the gear pitch is important since the PTO gear must have the same pitch as the transmission gear to function properly.
Another measurement term to be familiar with is gear ratio. Modification of the operating speed of the engine to the PTO driven device can be created through the gear ratio. To understand the PTO gear ratio, it measures the revolutions of the small and large gears. Looking at a smaller gear with 12 teeth driving a 24 teeth gear, the small gear makes a revolution with the larger gear only making half a revolution during the 1 small gear revolution. This means that the speed of the larger gear is half of the smaller gear, but the torque and twisting force is twice of the smaller gear.
The gear ratio in this scenario equates to the number of teeth in the driven gear (24) divided by the number of teeth in the driving gear (12). This results in a gear ratio of 2 to 1. The change in torque in this scenario is 1 to 2 resulting from dividing the number of teeth in the driving gear (12) over the driven gear (24). With the assumption of knowing the engine horsepower and the revolutions per minute (RPM) of the smaller gear, torque can be determined.
T = Horsepower x 5252/Speed (RPM) = Lbs. Ft. Torque
(As you can see from the above photograph, the two gears would lock as so with the red marked teeth)What does the gear ratio mean to me?
Product series can have multiple gear ratio options or have just one gear ratio option. To select what ratio makes the most sense, you must know the RPM you want your vehicle’s engine running at for the application and the required operating speed of the driven equipment being used in the application. The ratio of a series of gears creates the speed for the output shaft. Those gears include the input driver gear, the input ratio gear, and the output ratio gear. Their relationship to one another will determine how fast the output of the PTO is spinning in relationship to the engine. The required speed for the driven equipment must be known in order to select the proper PTO ratio. When utilizing pumps, flow rate and displacement are needed to be determined beforehand to make sure the pump input shaft will work with the given speed from the PTO.
210 Series PTO & 524 Series Rear Mount PTO
When looking into specific product series offered by Parker Chelsea, we want to highlight two different scenarios for series model codes. Starting with our new 210 Series for 2020 Ford Super Duty 10R140 transmissions, this series only has one gear ratio being 46/36 (internal ratio). When all of the gears in series are considered, the final output ratio is 144% of the engine speed. With this gear ratio, and using a 90% efficiency rating, specific pump options are offered for the 210 Series which include the CGP-P11, PGP-315 and P16 pumps. It is important to remember pump productivity is determined by the pump size in relation to the pump speed. Therefore, certain pump options may be more suitable than others depending upon the requirements of the application.
The 524 Series Rear Mount PTO is a little different compared to the 210 Series in relation with the gear ratio(s). The 524 Series has gear ratios of 1:1.00, 1:1.33, and 1:1.80. The design of the PTO itself is a two gear mechanically shifted Rear Mount PTO that is attached to rear mount apertures of a transmission. Rear mount apertures are becoming more common in the U.S. with European based transmissions becoming more popularized in the U.S. market. With the three gear ratios, this leads to different torque ratings being available in the market therefore increasing the number of applications that can be used with the 524 series along with optimizing the driven equipment.
Learn more about our 524 Series rear mount and 210 Series ten speed PTO today.
This article was contributed by Michael Mabrouk, marketing leadership associate, Chelsea Products Division, Parker Hannifin Corporation.
27 Mar 2020
Parts 1 and 2 of this series discussed the theory behind CSR testing and what to look for in a CSR result curve. This 3rd and final section will focus on how to use CSR data and apply it to real world applications and how to incorporate it into a material specification.
For the reasons discussed previously, it is important to view a full CSR curve, rather than a single data point, and to resist the urge to draw conclusions from incomplete data. For example, Figure 1 compares a FKM to an HNBR material. Because the fluorocarbon material has a larger viscoelastic loss within the first 24 hours of the test, it appears to be worse (less retained seal load) than the HNBR for most of the test duration. However, the slope of the HNBR curve is steeper than that of the fluorocarbon, and the curves of retained load force cross at about the 2,300 hour point. If these curves are extrapolated, the HNBR is predicted to reach the point of zero residual load force at 4,262 hours, whereas the fluorocarbon is not expected to reach the same point until 8,996 hours have elapsed. Had the HNBR material been selected for this application based solely on the higher percent retained load force observed at 1,008 hours, the end user would have achieved roughly half of the service life they could have enjoyed had they selected the FKM compound instead.
Figure 1: An HNBR and a fluorocarbon in engine oil.4 Limitations of CSR data
Several caveats remain in attempting to use CSR curve data to predict real-world performance. First, a CSR procedure cannot mimic real-world application conditions. In fact, it is not intended to. CSR testing is meant to be an accelerated aging test, where specimens are exposed to constant temperatures hotter than anticipated in the actual application. While some continuous CSR test machines are capable of temperature cycling, no CSR test can realistically replicate the actual temperature conditions, pressure fluctuations, or vibration seen in a real-world application. Second, CSR testing cannot replicate actual fluid exposure conditions seen in typical seal applications. CSR testing completely immerses a rubber specimen in a small amount of fluid that is kept at a high temperature – typically hot enough and with enough air exposure to cause the fluid to degrade. In a real-world application, a seal is usually installed in a groove with fluid exposure on one side and air on the other. In many applications, the fluid is contained within a sealed system that minimizes oxidative degradation of the fluid. Third, there is as yet no definitive correlation between the onset of leakage and residual load force, regardless of whether that force is expressed in absolute terms (Newtons or pounds-force, for example) or as a percentage of the initial developed load force. Finally, because low temperatures are more challenging for a seal, cycling the temperature to include load force measurements at -40°C would be considered a worst-case scenario. Continuous measurement CSR devices are now commercially available with the capacity for running such a temperature cycle, but their use to date has been extremely limited due to the cost of the equipment.Other considerations
Several factors should be considered before incorporating CSR testing into a material specification. CSR is a more expensive procedure than compression set, and it requires dedicated and expensive test equipment. As a result, it is not always appropriate to replace compression set testing in a material specification with CSR testing. Second, establishing limits for “what good looks like” should never be done arbitrarily. It is extremely difficult to convert a real world application service life into a number of test hours at a set temperature. Therefore, it is more practical to start with a material that is known to maintain a satisfactory service life in the application, test it for CSR at a relevant temperature, and establish meaningful limits based on the performance of that material. Finally, resist the temptation to get too exotic with specification limits. For example, it may seem valuable to impose specification limits related to the slope of the CSR curve or to the extrapolated “time to zero load force”. These can be valuable tools for gathering engineering insight, but they are far too complicated to incorporate as specification limits. CSR is a more complicated test than compression set, and it requires more “homework” to set proper limits and test conditions.
In conclusion, Compressive Stress Relaxation is a powerful tool for comparing the performance of two or more materials in a particular application, provided it is done on an apples-to-apples basis. It also serves as a reasonable means of (roughly) estimating the long-term service life of a seal material in a given application. There are too many assumptions for it to be used to guarantee a specific level of performance, and there remains much work to be done in correlating results to real-world observations, but it currently offers the best laboratory-scale means of evaluating a seal material for long-term use in a given application.
26 Mar 2020
Quick connections for high-pressure, hydraulic applications have evolved immensely over time to satisfy new processes and operational needs. As industries advance their capabilities, the demand grows for coupler capabilities. Today, couplers must ensure fluid handling applications meet both safety and regulatory standards while simultaneously provide optimized containment of a wide range of fluids that can have different operational conditions.
Operators have continually depended on reliable connections for a “non-spill” experience under the most extreme conditions, such as temperature or high pressure. Manufacturers saw this as an opportunity to introduce new and enhanced couplers to the market.Flush face valving delivers near-zero spillage
Couplings, specifically non-spill, are engineered to combat hydraulic leaks and spills with a unified design incorporating sophisticated components. For reference, the term “non-spill” regarding a coupling means a specific type of connector can reduce fluid spillage to near zero whenever a coupling is connected and disconnected. Designed initially as heavy-duty metal couplings for high-pressure, industrial applications, non-spill couplings have evolved into a variety of materials to complement a wide range of applications requiring minimal spillage and air inclusion.
The flush face design became a significant advancement in quick coupling architecture. A “no-drip” valve means no more than a coating of liquid will appear on the valves’ surface, establishing repeated dripless connections and disconnections for a cleaner, safer work environment. Also, inclusion, which represents the air put into the fluid system during each connection, is drastically reduced through a flush face valve. The benefits of near-zero spillage and air inclusion have become critical in many applications, from heavy-duty construction equipment to hydraulic hand tools and general industrial machinery.Parker’s non-spill quick couplings
Parker is the global leader in quick couplings, delivering a spill-free and lasting performance, with a wide range of non-spill coupling solutions to fit versatile fluid applications. The FEM Series, FET Series and 59 Series all provide minimal fluid loss and air inclusion, as well as chemical compatibility when necessary.FEM series
This non-spill quick coupling satisfies the design and performance requirements set forth by the ISO 16028 International Standards for quick coupling interchangeability. Featuring a push-to-connect design, FEM Series delivers an extra level of security for simple connections without causing any joining, crimping or soldering materials, eliminating spillage and air inclusion during connecting and disconnecting.
In addition, Parker provides an optional FEC male nipple, which allows connect-under-pressure capabilities with the FEM female coupler. This option is designed for applications where residual pressure makes connection difficult.FET series
The FET Series non-spill quick coupling, engineered for reliable performance with equipment experiencing powerful impulses, accommodates the most demanding hydraulic applications. Parker’s FET Series couplings connect under pressure at 6,000 psi and disconnect up to 2,500 psi in environments that desire the security of a threaded connection under residual pressure. These couplers are built to operate under high-impulse mobile circuits, including excavators, and oil and gas equipment, such as umbilical lines and mobile drill rigs. Constructed of high-grade materials and a stainless steel valve, the FET Series features a robust Brinell resistant design and plating for extended durability and corrosion resistance.59 series
Ideal for use in high impulse applications with multiple high-pressure hydraulic lines, the 59 Series ensures consistent connections and disconnections under residual pressure. A powerful ACME thread utilizes a double start feature and allows a full connection to be completed in 2 – ½ turns, saving time and eliminating frustration. Its size and shape of the heavy-duty ACME thread make the coupling resistant to damage, easier to clean and ready for operational use.
An internal bearing between the collar and body eases resistance and minimizes the challenge of handling pressurized lines. In addition, the coupler and nipple have non-spill stainless steel valves and can be connected under pressure up to 5,000 psi and disconnected under a pressure of 2,500 psi.
Contributed by Lori Aus, product sales manager, Quick Coupling Division, Parker Hannifin.
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25 Mar 2020
Electrically conductive elastomers are elastomeric polymers filled with metal particles. They can be grouped by filler type and elastomer type. Then within each of these classes, there are standard materials and specialty materials.
Parker Chomerics manufacturers electrically conductive elastomer gaskets, also known as EMI elastomer gaskets, under the CHO-SEAL brand. We won't get so much into gasket configurations and dimensions here, we'll just stick to classes of materials. So what is available? Let’s find out.
Conductive elastomers are metallic particle filled elastomeric polymers, the particles giving the shielding performance and the polymer making them “rubber." There are many materials within this generic material type, but we'll focus on the below.
Setting up the grades of conductive elastomers by filler types involves six different particles:
Three types of elastomer material
All of these materials are cured or cross linked when the gasket is made. The cure either happens with heat or atmospheric moisture.
In general, for small cross sectional electrically conductive elastomer shapes, the smaller the particle the more producible the part will be. Particle fillers have little to do with mechanical properties of the gasket except that they simply increase hardness.
Now that you have more information about how to select particle and polymers for electrically conductive gaskets, download or Electrically Conductive Elastomer Handbook and get started today!
This blog contributed by Jarrod Cohen, marketing communications manager, Chomerics Divison.
24 Mar 2020
The end point
The first and most basic point of understanding is the end point. Does the material continue to maintain contact pressure throughout the test, or does it fall to zero (below the detectable limit of the load cell) before the end of the test? While there is no definitive correlation from residual load force to onset of leakage, it should be intuitive that a material that completely relaxes and loses all contact force is likely to leak in application. Anecdotally, multiple customers have reported that the load force must drop to very close to zero for leakage to occur in their particular test apparatus. While this is good guidance, these anecdotal reports should not be taken as a definitive answer that applies in all circumstances.
Specifications are often written such that a minimum of 10% of the initial contact load force must remain for a passing result. In practice, there is nothing special about 10%. This is a semi-arbitrary value that ensures a material continues to apply some non-zero load force to the mating surfaces, with some safety factor to ensure that it does so even after all normal test variations are considered. In practice, this appears to be a conservative limit, there is nothing magical about the 10% number.
The loss of compressive load force can be broken down into three different types of phenomena, each with its own time frame. All rubber materials relax viscoelastically when initially compressed, and this loss stabilizes within the first 24 hours. That initial drop seldom has much direct impact on real-world applications. However, in the specific case of an assembly having neither a compression limiter nor solid-to-solid contact, meaning the assembly torque of the fasteners is controlled solely by compression of the seal, this will be observed as “torque fade” if the fastener torque is rechecked a day or two after assembly. In such a case, Parker recommends against retorquing the fasteners unless leakage is observed as this retorquing can easily result in damage to the seal from excessive compression.Solvation effects
The second set of phenomena to resolve are solvation effects that occur when an elastomer is immersed in a liquid test media. The rubber material will absorb some amount of test fluid, causing some swelling of the rubber and a small increase in load force. When this happens, the test fluid may extract liquid constituents from the rubber, resulting in shrinkage of the seal material and a loss of load force. These processes occur simultaneously, and both typically reach equilibrium within the first 72 hours. However, the net impact on the measured load force will only be noticeable if the volume change is significant.Degradation
The third set of phenomena are degradative effects caused by high temperatures and chemical reactions. These reactions are ongoing and cumulative. If the test temperature remains constant, the rate of degradation will remain constant, as well. Unfortunately, there is no way to distinguish what percent of any degradation is due to thermal effects versus chemical effects from a CSR curve. Comparing a CSR output curve to one generated from testing in an inert control fluid at the same time and temperature may allow a user to isolate thermal effects from chemical ones, but it must be known that the control fluid does not also produce chemical degradation of the rubber material.
Ultimately, it is more important to consider the slope of the curve after the initial drop than the initial drop itself. The material should stabilize to a relatively flat line, and the slope of that line reflects how the material responds to thermal and chemical aging effects. A curve with very little slope (Figure 1) is extremely stable long-term, whereas as a CSR curve that shows a steeper negative slope (Figure 2) means the material is continuing to degrade due to chemical and/or thermal effects in that fluid and at that temperature. This does not mean the material is incompatible with that environment, but the continuing losses mean the end of service life point (onset of leakage) would be expected relatively soon after the end of the test.
Figure 1: A fluorocarbon in engine oil at 150°C shows very little change after the initial relaxation response.
Figure 2: An HNBR in engine oil at 150° shows ongoing degradation after the initial relaxation response.
In summary, much knowledge about how a material will respond in an application can be gleaned from Compressive Stress Relaxation testing if one knows what to look for. Watch for part 3 of this series, where we will focus on how to use the understanding gained from CSR testing and how to incorporate it into a material specification.
For more information or assistance with your application, contact our applications team at email@example.com or chat online by visiting Parker O-Ring & Engineered Seals Division website.
19 Mar 2020
The principles and practices of lean manufacturing are widely used in industries across the globe to continuously improve processes, drive efficiencies and reduce costs.
Even in biopharmaceutical manufacturing where validation and regulatory requirements are high, lean can be used to improve processes, meaning more life-saving product can reach patients quickly.
Technology has been developed to support biopharmaceutical manufacturers, CMOs and CDMOs on their lean journey and at Parker we have worked closely with industry to develop a system that can improve operational efficiency, accuracy and safety.
Parker’s SciLog® FD System automates, standardizes and encloses final bulk filtration and dispense operations. It can support companies in addressing the eight wastes of lean: Transportation, inventory, motion, waiting, overprocessing, overproduction, defects, and safety.
As an automated, standardized and enclosed single-use system, it has many advantages over manual operations. It can increase efficiency, reduce process variation, protect the product and operator, and reduce risk.
Here is how the SciLog® FD System can help manufacturers tackle the eight wastes, and support them in implementing lean production strategies.
As the process takes place in a single, enclosed system, the movement of products and materials is reduced. The SciLog® FD System can combine two unit operations: the sterile filtration of bulk drug product and its dispense into bottles or bags. As both of these steps can be performed on one system, transport of material is reduced. Once dispensed into bags or bottles, the drug product can be easily transported for freezing or cold storage.
The use of the SciLog® FD System simplifies the supply chain, with the hardware and consumables, including single-use manifolds, designed together and available from a single source – Parker.
Using an automated system means that the motions associated with a manual operator – for instance operating pumps and valves – are removed from the process. All of the valves are controlled automatically, with intelligent feedback from the SciLog® single-use sensors which are part of the system.
Moving materials in a laminar air flow using aseptic technique can be challenging and has a high training requirement. Reducing the amount of movement of product through the use of a closed system reduces the risk of contaminated product. The SciLog® FD System allows recipe-driven processing, sampling and integrity testing — all taking place on the one enclosed automated system limiting unnecessary motion and associated risk.
As the SciLog® FD System is automated, it cuts down on an operator’s waiting time in between different stages of the process. This means that staff can be utilized more efficiently. For example, a recipe can be programmed to carry out an automated filter integrity test and, while this takes place, the operator can perform other activities such as checks or paperwork completion.
Time-consuming, and potentially inconstant tasks that would have been carried out manually are now automated. For instance, the SciLog® FD System generates automated batch records - an alternative to the operator having to complete forms manually (and reducing the risk of transcript error). There is also an integrated label printer with labels suited to cryogenic storage.
Manual fill can be inaccurate - and human error can lead to more product being transferred to a bottle than is required. Clearly this can have a significant impact on production and, given the high value of the product, can be financially damaging too. By automating the bulk fill process, costly inaccuracies can be avoided. In the SciLog® FD System, load cells located under receiving containers ensure direct measurement for high dispense accuracy.
An open process which relies on manual handling can result in contamination of a product and batch loss. Enclosing the process means that the product is protected and the risk of any contamination is greatly reduced. In addition, standardization and automation eliminate process variability and enables batch repeatability. Standardized, reliable programming ensures repeatability and control in the process.
As calibrated SciPres® single-use pressure sensors are included in the SciLog® FD System, operators can ensure that validated pressure limits are not exceeded, protecting the manifold and controlling the differential pressure over the filter.
Utilizing a fully enclosed process means the product is protected from contamination by the operator, but crucially also that the operator is protected from potentially highly potent molecules.
There are also additional advantages to using Parker’s SciLog® FD System which supports the application of lean in biopharmaceutical manufacturing. Standardization means that training is made simpler and easier, and by using a single-use system, change over times can be significantly reduced. The installation of manifolds in the system is quick and easy, again reducing labour costs and time spent on manual tasks.
To learn more about how the SciLog® FD System can help you tackle the eight wastes of lean, please visit our webpage.
This post was contributed by David Heaney, market development manager, Parker Bioscience Filtration, UK
Parker Bioscience Filtration specializes in automating and controlling bioprocesses. By integrating sensory and automation technology into a process, a manufacturer can control the fluid more effectively ensuring the quality of the final product. Visit www.parker.com/bioscience to find out more.
19 Mar 2020