impact crusher how does it work

impact crusher working principle

impact crusher working principle

Starting from the base working principle that compression is the forcing of two surfaces towards one another to crush the material caught between them. Impact crushing can be of two variations: gravity and dynamic. An example of gravity impact would be dropping a rock onto a steel plate (similar to what goes on into an Autogenous Mill). Dynamic impact could be described as material dropping into a rapidly turning rotor where it receives a smashing blow from a hammer or impeller. Attrition crushing is the reduction of materials by rubbing; primarily a grinding method. Shear crushing is accomplished by breaking along or across lines of cleavage. It is possible, when required, for a crusherto use a combination of two or three of these principles.

Rapidly increasing operating costs for minerals beneficiating plants continue to be the biggest single problem in maximizing profitability from these operations. The average world inflation rate has been increasing over the last decade and shows little sign of easing. The threat of continued increases in the price of fuel oil will eventually increase the cost of electrical power, in direct proportion for most users. This will undoubtedly cause closure of some lower grade ore bodies unless energy utilization efficiencies, particularly in comminution, can be improved.

Most of the recent literature concerning comminution performance improvement has been directed at grinding mill performance. It can be expected that more refined control systems will improve the overall milling energy efficiency, which is normally the largest single cost component of production. However, published gains by such methods to date appear to be limited to something less than 10%.

The second largest cost for comminution processes is normally that for wear metal consumed in grinding operations. Allis-Chalmers has continuing -research programs into all forms of comminution processes involving crushing and grinding. Improved crushing technology shows the way to reducing both energy and wear metal consumption mainly by producing finer feed which will improve downstream grinding mill performance.

A new testing procedure for studying crushing phenomena, presently being perfected by Allis-Chalmers, is described for the first time. These bench scale laboratory tests will give more accurate prediction of both energy requirements and size distribution produced in commercial crushing processes. As a direct result, this machine will allow more accurate comparisons to be made in capital and operating cost expenditures for various combinations of crushing and milling processes.

These new testing procedures can be run on small samples including pieces of drill core material. They could be part of testing and feasibility studies for most new concentrators. The same methods can be used to determine likely yield of various sized crushed products and, therefore, benefit crushed stone producers.

The theoretical and practical phenomena concerning comminution processes have received considerable attention in the literature and are not discussed here in any detail. Instead, the breakage studies in this paper are based on an empirical treatment of the fundamental relationships between energy and the size distributions of processed particles that have been observed both in the laboratory and in large-scale, commercial cone-crushing operations.

Because of the bewildering number of variables encountered when studying comminution processes, most investigators have preferred to assume that the size distribution generated in milling and crushing processes bears some relatively fixed relationship such as those described by Gates-Gaudin-Schuhmann1 or Rosin-Rammler.

Fred Bond, in his Third Theory of Comminution, used the former, essentially assuming that size versus cumulative percent passing that size was represented by a straight line of assumed slope 0.5 below the 80% passing size. Based on this assumption, Bond derived his well-known relationship:

The Work Index for rod and ball mills can be determined from laboratory tests and, as demonstrated by Rowland, the relationship gives us a reasonably accurate tool for the design of rotary grinding mill circuits.

Bonds methods have been less successful in predicting fine crushing performance, however, primarily because the typical crusher feed and product distributions do not meet the assumed conditions necessary for the satisfactory application of his equation (see Fig. (1)).

It is most evident that the curved lines appearing on Fig. (1) do not represent a Gates-Gaudin-Schuhmann size distribution. It is therefore not surprising that Bonds procedures do not work well in this situation. The Rosin- Rammler distribution has also been found inadequate to generally describe crusher products.

Work during the early 60s led to the concept of comminution as a repetitive process, with each step consisting of two basic operations the selection of a particle for breakage and the subsequent breakage of this particle by the machine. In this approach, the process under investigation is modelled by combining the particle selection/breakage event with information on material flow in and out of the comminution device.

Most workers who have used this approach have considered size reduction to be the result of the mechanical operation of the comminution device. This mechanical operation consumes the energy, and size reduction is merely a result of this energy consumption. This viewpoint is reasonably valid for tumbling mills where energy input tends to be constant and the proportion of the energy that is usefully consumed in particle breakage is low (<10%). It does not appear to be valid in compression crushers, however, since breakage energy is a significant proportion (>50%) of the total energy input to the crusher and markedly different power rates (energy input per unit of crusher feed) can be obtained by varying ore feedrates and/or crusher parameters such as closed side setting. It will therefore be necessary to include energy information in any model of the crushing process before it will be possible to accurately predict crusher performance. The inclusion of this energy-size information will significantly increase the complexity of these models.

The single-particle breakage event has been the subject of several studies. Most of these have utilized only sufficient energy to break the particle and do not simulate commercial crushing operations where energy levels are such that catastrophic repetitive breakage usually takes place. This approach to the study of comminution processes does yield valuable information, however, and it is unfortunate that it has not received greater attention.

The Bond Impact Work Index method has been an industry standard for the determination of crusher power requirements but was originally developed to ensure, that sufficient power was connected to primary gyratory crushers. In this method, pieces of rock are fractured by trial and error in the test device shown in Fig. (2), until sufficient impact energy has been applied to break the rock.

Normally, the rock breaks in halves, and in most tests only two and seldom more than three large pieces are observed after fracture. No size distribution information is used in calculating the Bond Impact Work Index from the formula:

KWH/tonne). The procedure works quite well for this type of crusher but tends to understate power requirements in fine crushers where power rates are typically much higher (upwards from 0.25 KWH/tonne).

Because of this, a research program was instituted by Allis-Chalmers Comminution Task Force Committee to break rock in a manner more analogous to that observed within commercial fine crushers. A pendulum type test device similar in most respects to that developed by the United States Bureau of Mines and shown diagrammatically in Fig. (3), was built and has been used in an extensive test program to determine whether it would be possible to predict cone crusher performance.

The rock samples selected for crushing in this device are usually minus 38mm (1-), plus 19mm () in size. The sample rock is weighed and then placed between the platens. The end of the rebound platen is placed in contact with the rebound pendulum and the crushing pendulum is raised to a predetermined vertical height which depends on the size of the sample. The crushing pendulum is then released after striking the crushing platen and breaking the rock, the remaining energy is transferred via the rebound platen to the rebound pendulum. The horizontal distance that the rebound pendulum travels is recorded by displacement of a marker and is subsequently converted to a vertical height.

where Ec = crushing energy E1 = crushing pendulum potential energy (before release) KE = kinetic energy of the two platens E2 = rebound pendulum maximum potential energy (after crushing) EL = system energy loss (sound, heat, vibration)

The system energy loss, EL, is determined by plotting EL as a function of the initial height of the crushing pendulum with no rock present. The major portion of this loss is by vibration. It is felt that the difference between system energy losses with and without rock present in the system is minimal as long as enough initial energy is supplied to result in a small elevation of the rebound pendulum.

The fragments from several rock samples broken under identical conditions were combined for each of the size analyses reported in this paper. Bond Work Indices were also backcalculated from the data using the standard formula, i.e.

Confirmation of the ability of the procedure to provide information suitable for the prediction of crusher performance was obtained by taking feed samples from 31 commercial operations treating a wide range of rocks and ores. At the time of taking a feed sample for laboratory testing in the pendulum device, relevant performance data such as power, feed rate and size distributions for feed and product were taken on the operating crusher. Several thousand rocks have been broken during tests with the device over the past 3 years.

The first thing to notice from these graphs is that there is an extremely good family relationship within each set of size distribution curves. This is somewhat coincidental, since the pendulum curve is the product of a single particle-single impact breakage event and the typical crusher product curve results from multiple particle-multiple impact breakage, but is probably due to two facts:

In order to show that the pendulum product size distribution is sensitive to power rate, several tests have been run on the same feed material at different levels of pendulum input energy. Typical results are shown in Fig. (7) as Schuhmann size distribution (log-log) plots. It can be seen that increasing amounts of fine material are produced with increasing energy input. The same effect was previously demonstrated for an operating crusher in Fig. (1). We can, therefore, conclude from this

that net power rates will be the same in the pendulum and the crusher when the two distributions coincide (as they do in Figs. (4) thru (6). This permits us to determine the efficiency of power utilization in crushers and to predict the product size distribution which will arise from operating crushers at different power rates.

The Bond Work Index figures obtained by backcalculation from the pendulum data are compared with the Net Work Index values obtained from the plants in Fig. (8). The agreement is surprisingly good especially in view of the fact that the 80% passing values do not completely describe the total feed arid product size distributions. This agreement is probably due to the fact that the use of comparable energy levels in both machines gives rise to similar reduction ratios and product size distributions. Because of this, the pendulum test provides a good estimate of the Net Work Index when this is required for current design procedures.

The pendulum product distribution is a breakage function and can be used in models of the process to predict crusher product distributions for different operating conditions. As an example of this approach, Whitens model of the cone crusher, Fig. (9), has been used to simulate the situation given in Fig. (4). The result of this simulation is given in Fig. (10) where it can be seen that very good approximations of crusher performance can be obtained.

The writers are firmly of the opinion that results to date prove that the use of this pendulum device can give more energy-size reduction information in a form readily useable for crusher application. The data can be generated in less time and from a much smaller sample than is required for pilot plant testing. Our present pendulum tester is a research tool and is currently being modified for use in commercial testing of minerals and rocks. More details of this device will be given at a later date.

what's an impact driver, and how does it work?
 
 | the drive

what's an impact driver, and how does it work? | the drive

Whats better, acquiring tools or speed parts? The preference depends on a multitude of factors, but, I personally get giddy when it comes to new-to-me tools, especially when it comes to power tools that make life a whole lot easier.

None of the power tools in my collection deserve higher praise than my impact driver. Its a cheap model from a certain freight company that Ive used and abused for virtually any project Ive taken on since acquiring it. The impact driver is an undisputed garage champion thanks to its power, versatility and durability.

Its usefulness comes down to its function. Impact drivers are a little more tool than a fancy drill and a little less tool than an impact wrench. Today, The Drives top tool nuts will break down exactly what that means by exploring what an impact driver is, what its used for, and why it became my go-to device.

One of the primary purposes of a drill is to drive fasteners into materials. The use of rotational force provided by the motor and the pressure you supply with your hand makes this possible. Pretty simple, right? But what if the material is dense and tough to drill into? What if you hit a knot or a hard spot in the wood while you drill? Or what if a long faster has too much drag? You might think to simply add more pressure, but thats not always the best idea. The problem in doing so is that you end up overloading the motor, bogging it down, and risk damaging it.

An impact driver is designed to solve exactly these types of problems with a two-pronged attack. Impact drivers use motors that supply more significant levels of torque than a drill and they use an impact action that helps to drive fasteners through more rigid materials when under load.

If that sounds familiar, its because that impact action is similar to the function of an impact wrench and a hammer drill. In comparison, impact drivers arent as powerful as impact wrenches and hammer drills, nor are they as precision friendly as a power drill. However true that may be, the result of the design is a tool that lands somewhere in the middle of all three. You wind up with a tool that can be used in various settings with a compact size that compliments all projects.

The power created by an impact driver might seem like a minor miracle, but these helpful tools rely on reasonably simplistic mechanisms. The internals looks very much the same as a drill in that you have a motor that applies rotational force. Only its more compact to allow room for the hammer and anvil.

Just like with a drill, theres an output shaft. Only before the output shaft reaches the chuck or collet, in this case, theres an additional mechanism thats composed of a spring-driven hammer and anvil.

The hammer can cam away from the anvil and depress the spring when the system is under load. After it clears the anvil, it snaps back into position and spins freely until it strikes the anvil again. The collision of the hammer against the anvil creates the impact action. That impact supplies the force for the system to continue to drive a fastener into place.

Say youre driving fasters in a tight spot that you cant get a drill in, nor can you apply much pressure because youre at an awkward angle. The impacting action helps to drive the faster through whatever you need it to. It also delivers a shock that helps to free stubborn fasteners that a drill will struggle with.

You may be able to use a normal drill for either setting, but you can run into several issues. As we already said, applying too much force bogs down the motor and can ultimately kill your drill. Not only that, but the increased pressure is also hard on your wrists, which is never a good thing during a long day of wrenching.

The impact action and rotational force created by impact drivers allow the tool to be used for many things. But perhaps what truly boosts its versatility is that quick-change drive attached to the head.

Most impact drivers feature a quick-change collet that accepts bits that feature a 1/4-inch hexagonal shank. Drill bits, bit drivers, and all sorts of other goodies can hook right into this slot, allowing you to get to work on anything. Heck, you can even get a keyed-chuck with a 1/4-inch shank that will enable you to use standard drill bits in there. Again, its not as precise as a regular drill, but it comes in handy when you need to quickly put a hole in something.

Beyond that, possibly its most helpful feature is that it works with socket adapters that essentially turn your impact driver into a mini-impact wrench. Factor that in with everything else, and you can see why an impact driver comes in handy for virtually any project around the shop.

The most significant factor is that an impact wrench is a dedicated tool that features a permanently mounted -inch, 3/8-inch, or 1/2-inch socket drive. And because impact wrenches are explicitly intended for dealing with stubborn nuts and bolts, theyre generally far more powerful than impact drivers.

Because of this, an impact driver does not take the place of an impact wrench. The 1/2-inch socket adapter available for your impact driver will likely see little to no use because they generally dont provide enough power to break large hardware free.

Because you have the ability to attach sockets to your impact driver, you absolutely can use them for automotive projects. But dont expect it to perform as well as an impact wrench thats intended for this line of work.

Your working experience with an impact driver in this setting depends on the model you choose. Thats simply because some are more powerful than others. But because many fasteners are set in place with ample amounts of torque, its almost a guarantee that youll still use a wrench to break nuts and bolts free then use the impact driver to take it home.

Now, dont rule them out just because impact wrenches typically bring heaps more torque to the table. Something to love about impact drivers is that they arent overpowered to the point where youre always worried about stripping threads if you choose to use them to tighten something down. While its never wise to use an impact for tightening, you can (at your own discretion) get away with using impact drivers to gingerly set hardware in place before torquing.

Furthermore, the ability to use one as a drill makes them an excellent choice for driving sheet metal screws and other miscellaneous tasks. Again, a drill is superior when precision is of utmost importance. However, the lightweight and compact design of impact drivers paired with higher torque output make them perfect for a variety of automotive-related tasks.

Its easy to come to the assumption that all impact drivers are the same, especially when the market is dominated by cordless impact drivers. Although it does make sense that consumers prefer battery-powered impact drivers due to their convenience, its not your only option. That said, lets talk about the different types of impact drivers that you have available to you.

Corded impact drivers arent as easy to come across, but they do exist. Rather than relying on a battery, these variants tap directly into a power outlet. The obvious pro is that you dont need to worry about charging the battery or keeping a spare around to prevent any hiccups. The drawback is that it can work against the convenience factor of the compact design. The length of the power cord and fumbling with it can make it very difficult to work in tight spaces.

Cordless or battery-powered impact drivers are by far the most common variant. Without a cord snagging on the car or anything else in the garage, they are far easier to use in any setting. Its important not to assume that all cordless options are the same, though. Different lines offer different levels of power, and youll even see that you generally have two different sizes to choose from. While the traditional layout is already pretty small, there are compact models available to you. The compact versions arent as powerful, but they are a clear choice for workspaces that inspire claustrophobia.

Officially known as a pneumatic impact screwdriver, this type of impact driver is far less common in todays electricity-driven world. These models offer all the typical benefits of an impact driver, only it relies on air pressure rather than electricity. Obviously, that genetic alteration does make them lighter and possibly more powerful, but it does mean youre reliant on an air compressor to work. For more information about the benefits of an air compressor, visit our guide to pneumatic tools.

A manual impact driver is not a power tool, but its worth mentioning. On these tools, the system relies on you attaching a bit to the drivers nose and striking the rear of the tool to create rotational force. At a very base level, its like using a hammer and chisel.

They arent great for extensive jobs that can be handled by the types mentioned above, but you can create a tremendous amount of force thats necessary for releasing particularly stubborn hardware. And its always good to have a manual backup in case all of your batteries die.

A: Yes. Impact drivers are intended to take the place of a drill when driving long fasteners or dealing with harder materials. The quick-change collet allows the user to attach many different bits specifically intended for such a purpose. The thing to remember is that impact drivers are more powerful than drills. While that might seem like a good thing, it ultimately decreases the tool's precision and increases the likelihood of stripping fasteners.

A: Not typically. While technological advancements are likely to create exceptions to the rules, impact drivers generally arent powerful enough to remove lug nuts. You can, however, use them to unthread lug nuts after theyve been broken free by a breaker bar or tire iron.

A: You should not use an impact wrench any time precision is necessary for drilling holes or torquing down nuts and bolts. Impact drivers are meant to replace drills in certain settings, but the impacting action and increased power arent known for leaving behind the cleanest fit and finish. And because they are powerful tools, you dont want to use them for tightening nuts and bolts down. Even though they arent as powerful as impact wrenches, there is still the risk of over-torquing and stripping threads.

A: Both. While the impact driver is versatile, its not a drill. Drills are ideal for a project that requires total precision. So, if youre putting the finishing touches on a project, a drill is the right tool for the job. However, if youre trying to install long fasteners or drill into harder materials, an impact driver will make life a lot easier. Ultimately, these tools do things that the other cant, meaning both have specific settings to perform in.

A: You can. But the fact of the matter is that regular sockets are not designed to withstand the impacting action of the tool, and they are likely to crack or shatter under load. That said, you should use impact sockets for impact wrenches and even impact drivers. Ive personally used regular sockets on my driver and never ran into such an issue, but there is the right tool for the job, and its best to use impact sockets for these applications.

Were always on your side, and we get that most of you are visual learners. Not only that, it can be tough to put the exact workings of these tools into perspective without visual aid. This video not only provides a breakdown of an impact driver but does a great job at explaining how they all work together!

Were here to be expert guides in everything How To related. Use us, compliment us, yell at us. Comment below, and lets talk! You can also shout at us on Twitter or Instagram, here are our profiles. Got a question? Got a pro tip? Send us a note: [email protected]

how does an impact crusher work? | rubble master

how does an impact crusher work? | rubble master

Impact crushers reduce mineral materials such as concrete, asphalt and natural rock in size to produce a valuable commodity product. A fast spinning rotor throws the material against a solid stationary impact wall. The striking and impacting causes the material to shatter into smaller pieces. The result is a very homogenous and cubical product leaving the crusher box.

The horizontal shaft impactors are the most common impactor type that can be used in recycling, primary and secondary crushing applications. This type impactor will take reasonable size pieces and produce small output material.

The crusher box includes a rotor with hammers (also called blow bars). Depending on the rotor style you will have either 3 bars or 4 bars. Hammers are cast iron replaceable wear parts that are actually in contact with the material. They are designed to withstand the many impacts of the material. The impact wall (also called apron) has several crushing stages and is armoured by thick wear plates.

Once the hammer hits the big material entering the crusher box it is thrown against the wall and starts ricocheting between hammers, wall and other material particles. As soon as the material is small enough the fit in between the rotor and the lowest crushing stage of the impact wall it will leave the crusher box at the bottom.

The beauty of impact crushers is their versatility in terms of input material and output size. There are many different designs out there but generally speaking impact crushers can produce material from 3" down. The smaller the input material the harder it gets to crush. The output gradation can be adjusted through various settings.

On most crushers this works hydraulically. The aprons need to be adjusted when you want to produce a different output material or when you need to readjust your crusher settings to accomodate the wear progress.

RUBBLE MASTER impact crushers use a simple design to change the crusher setup easily, quickly and safely within minutes. The unique proprietary crushing chamber design allows operators with limited impact crushing experience to operate our machine efficiently from day one.

united nations: definition, how it works, its effect

united nations: definition, how it works, its effect

The U.N.'s founding charter mandates four ambitious purposes. It maintains international peace, which is a full-time job in itself.The U.N.'s other three missions help to achieve that overarching goal.It fosters friendly relations between its members, it solves international problems and promotes human rights, and it harmonizes its members' actions.

TheGeneral Assemblyis composed of representatives of all member states. It creates the mandates that guide the day-to-day work of the boards and councils under it.The General Assembly meeting lastsfor several weeks in September of each year, and it gives world leaders a chance to come together and form working relationships.

TheSecurity Councilis the most powerful U.N. unit. Its mandate is to keep the peace. The five permanent members areChina, France,Russia,theUnited Kingdom, and the United States. The General Assembly also elects 10 non-permanent members that hold two-year terms.

All U.N. members must comply with Security Council decisions, and the Council sends peace-keeping forces to restore order when needed. The Council can impose economic sanctions or an arms embargo to pressure countries that don't comply, and it authorizes the U.N.'s members to take military action if needed.

TheEconomic and Social Councilconducts analysis, agrees on global norms, and advocates for progress in the areas of sustainable development, humanitarian work, and financial development. It forms partnerships as needed and oversees joint U.N. action to address related issues.

TheSecretariatcarries out the day-to-day work of the organization. It has several departments and offices that carry out distinct responsibilities. The Security Council nominates its leader, the Secretary-General.

The U.N. is not a government and has no right to make binding laws. Instead, it uses the power of persuasion. The U.N. committees negotiate multilateral agreements that give more teeth to its policies. Combined, they form a body of international law.

Every member votes in the General Assembly meeting, so the U.N.'s decisions reflect the prevailing values and goals of the majority of its members. Thus, countries that don't comply know they are in the minority.

There are 193 members of the U.N. The United States recognizes 195 countries. The two that aren't U.N. members are Kosovo and the Holy See. Russia won't allow Kosovo to become a member because it still considers it a province of Serbia. The Holy Seehas not applied for membership, although it has "permanent observer" status.

Notably, the U.N. made Palestine a "non-member observer state" status, even though the United States considers it to be part of Israel. China replaced Taiwan, which it now considers a province.

All peace-loving countries that are willing and able to carry out their obligations under the U.N. charter can join the UN. Nine of the fifteen members of Security Councilmust approve without any of the five permanent members voting against membership. Then, two-thirds of the General Assembly must also approve the membership.

On October 24, 1945, the first 50 nations who were members of the U.N. ratified its charter. U.S. President Franklin D. Roosevelt (FDR) lobbied for the U.N.'s creation even during World War II. In the Declaration of the United Nations, the Allies pledged to work together to stop the Axis. The four major Allies were the United States, the United Kingdom, the Soviet Union, and China.

FDR's administration worked with Congress to create a U.N. charter that had its support. President Harry Truman continued the effort after FDR's death. On June 26, 1945, the members created the U.N. Charter at the San Francisco Conference. Trumanmade sure that Congress ratified it right away.

The United Nations is the second attempt at a global peace initiative. In 1919, U.S. President Woodrow Wilson pushed for the League of Nations after World War I. The United States was not a member. Congress refused to ratify membership, fearing that would pull the United States into countless wars. Many felt the League failed because it could not prevent the outbreak of World War II.

Within the U.N., there are some well-known agencies that carry on its work. TheInternational Atomic Energy Agencyhelps to prevent nuclear proliferation and possible annihilation by a worldwide nuclear war. Below are several other U.N. system organizations and their functions:

research impact: what it is, why it matters, and how you can increase impact potential

research impact: what it is, why it matters, and how you can increase impact potential

Every drop of funding now seems to come with requirements around achieving and demonstrating broader impacts. Not many of us disagree with that in principle, but what does it mean in practice? How is impact actually achieved? How can you measure it? What can you actually do to accelerate it? Heres what our co-founder Charlie Rapple had to say in a recent webinar.

While there are some subtle differences, they broadly agree that impact means demonstrable and beneficial change in behaviours, beliefs and practices. At Kudos, we like the simplicity of this definition from Julie Bayley, Director of Research Impact at the University of Lincoln:

The real world part is key. Traditionally, assessment of impact has focused too much on academic impact whereas, in reality, impact is measured by indicators of change outside universities and research institutions, in the real world.

Having defined impact at this high level, its then possible to define a number of types of impact. Professor Mark Reed, Director of Engagement & Impact at Newcastle University, has analyzed impact case studies from around the world, and proposes ten types of impact:

Professor Reeds book, The Research Impact Handbook, is highly recommended even required reading if youd like to learn more about each of these areas, and how to understand the potential outcomes of your research in each area.

Impact is important because it helps keep us focused on the overall purpose, rather than the process, of research. Some of the legacy ways in which research is undertaken, communicated and evaluated have put up barriers between the work itself and those who may benefit from it. If we reduce the barriers between those producing research and those that can apply it to make change in the real world, we will be in a much better position to take on the grand challenges faced by the world today.

At a more everyday level, research impact matters to individual researchers because it matters to funders! The organizations that control research funding are under pressure to audit and evaluate their spending. For example, government policy makers want to know that they can rely on government-funded research to be high quality and highly relevant. Charitable funders need to be able to show donors how outcomes are being improved as a result of their donations. Institutions such as universities want to prove that they are the best, to attract more students, more researchers and more donations.

Because of the role that past and potential impact plays in funding decisions, this is literally a billion dollar question. There is no single, simple answer. But the question of what kinds of steps help to achieve impact has been widely considered.

An important point to remember in this context is that routes to impact are not, in themselves, impact. Running a workshop, producing a report, meeting a company are all activities that can help you progress through this process. But in themselves they dont represent provable change in the real world. It may be easier to track and measure those pathways than it is to identify the downstream outcomes that result from them.

Many researchers today are incentivized by their institutions to prioritize publication over impact. Until those incentive systems change, making time to develop and demonstrate impact can be hard to justify. However, things are changing, and fast! Mark Taylor, Head of Impact at the National Institute for Health Research, says that there are four broad reasons for measuring impact:

Measuring impact is notoriously difficult (hence many funders and systems still resort to using publication-based proxies such as the Impact Factor or citation counts which really reflect routes to impact rather than impact themselves, and even then, only within academic audiences). A more nuanced way of assessing impact is through narrative-based case studies, or by looking at tangible outcomes impact evidence that can be recorded and reported on via impact trackers or impact modules within university systems. Trish Greenhalgh writes and speaks eloquently on this subject. In her view, there is a trade-off between breadth and depth. If you want to measure the impact of every bit of research that everyone in a university has ever done, you have to use something that is easy to measure and probably automated. But if it is more important to get a rich and authentic picture of a sample of research programmes, this needs to be looked at in a lot more detail balancing measures with narrative. The Metric Tide report (produced by the Higher Education Funding Council in the UK) also concluded that quantitative measures cant yet replace qualitative assessments of quality and impact.

There is a lot more work to be done here! What is perhaps more measurable are the various steps from access to impact that we explored above; efforts to maximize reach, engage audiences, achieve and amplify change are all increasingly measurable. Over time, as those measures can be linked with ultimate outcomes, we will learn more about not only how to measure impact, but what to do to achieve it, too.

Charlie Rapple is one of the founders of Kudos, which has recently launched a new platform to help plan and manage communications to maximize impact potential of research. Charlie previously spent 20 years as a marketing and communications specialist in the academic sector, helping publishers and universities to communicate research.

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