Transfer of energy (pneumatic and hydraulic control systems)

the reasons for using pneumatic or hydraulic control systems in common engineering applications
the gas laws (including Boyles law and the ideal gas law) and how these are applied in engineering
the characteristics of 2D fluid flow over common objects, identifying laminar flow, stagnation points, separation points, turbulence and vortices.

Pneumatics and hydraulic control systems are unlikely to be something students have met in depth before. At KS3 some students will have been introduced to the idea that water pressure increases with depth, that air and water can be used to create a force and that pressure = force/area. However, these concepts are not regularly covered as part of GCSE science.

The uses of pneumatics and hydraulics are wide and varied. From agriculture to transport, to manufacturing textiles. This list includes resources that identify the applications of pneumatics and hydraulics as well as resources that explain the reasons this technology is used in context.

Students will need to grasp the idea of pressure and force multipliers in order to be able to apply the concepts involved in hydraulics and pneumatics in engineering systems.

The collection consists of videos giving contexts for the uses of hydraulics and pneumatics, a range of activities found on engineering education websites that give some ideas of activities and resources that have practical activities too. Towards the end of the list are two online information guides that include useful information that students and teachers of this topic may find useful.

Video

Quality AssuredCategory:CareersPublisher:Future Morph

The video in this resource has several aims and although the role of apprentices in service engineering is likely to be of limited relevance, the important information about approaches to safety is useful. The equipment demonstrated includes a hydraulic lift, and the concept of force multipliers is further explored with the associated practical activity into levers and pulleys. While this resource does not only deal with hydraulics and pneumatics it is a useful bridging resource to further content, showing force multipliers in different contexts.

Quality AssuredCategory:EngineeringPublisher:RNLI

This activity uses the context of emergency response vehicles on Britain's coastline. This vivid example brings home the need for reliable equipment and in particular the relevance of engineering design to an integral part of our emergency services. The propulsion systems rely on manipulating the area of a jet of water in order to increase the force exerted on the Shannon-class boats. This will build familiarity with practical approaches to pressure as well as the theoretical underpinning of force multipliers.

Image

Quality AssuredCategory:Design and technologyPublisher:Technology Enhancement Programme

This resource is a selection of diagrams that would be useful to incorporate into worksheets or presentations about pneumatics. Students could use them for labelling or as prompts to explain the principles to each other.

External link

This 2 minute 30 second video introduces pneumatics. It describes some of the advantages of using pneumatics in industry, such as it being fast so use for automatic manufacturing systems, useful in the food industry as air is clean so there is no contamination and equipment operates reliably. Reasons for the uses of pneumatics are discussed. It would be useful to set the context for a pneumatics lesson so that students can see the wide variety of uses of pneumatics in engineering systems.

This chapter from an online textbook provides useful background information for students and teachers about the principles behind the application of pneumatics and hydraulics.

The information is broken down by learning intention and key words are introduced well. Core ideas are bullet pointed to allow students to establish the basic knowledge they need to understand hydraulic and pneumatic systems. It begins with the advantages of hydraulic systems, the principles of using fluids (such as they do not compress) and goes on to introduce the idea of using pressure = force / area to make predictions and calculations about the transmission of a force through a liquid.

Using the arrows towards the top of the webpage it is possible to navigate further through the resource and get information about the types of fluid, reservoirs, and into further depth about other aspects of hydraulic systems.

This resource is useful background reading for students and staff related to hydraulics and pneumatics. It gives an explanation of how hydraulics can multiply the force applied and the difference between hydraulics and pneumatics. The website is american, as as such will require some alterations into metric units to make it usable in a UK classroom, however the experimental set up on the website could be repeated as a way to demonstrate force multipliers first hand. Using the link at the bottom of the ‘What is Hydraulics?” section to hydraulic applications takes the reader to further web pages which describe advantages and reasons for using such systems and a list of applications. Similarly the link at the bottom of the “What is Pneumatics?” section takes the reader to the same page, where it is possible to find applications for pneumatic systems.

This resource from the (American) National Science Foundation includes a 30 minute video about the following points:
• How fluid power works and why its attributes make hydraulics and pneumatics particularly well suited for getting work done under challenging conditions.
• Where fluid power is used in applications spanning the industrial spectrum—from the power needed in agriculture and construction to the precision required in intricate manufacturing processes and medicine.
• Why and how research in fluid power benefits all of us, bringing increased efficiencies to current uses and enabling new, innovative applications that improve our quality of life.
A useful resource to introduce the idea of hydraulics to students and again giving the impression of the wide and varied range of applications of this technology.

Students will find it useful to realise that hydraulic and pneumatic systems are force multipliers and allow easy accurate control of machinery to understand the advantages and reasons for using these systems in common engineering applications.

The resource is a comprehensive teaching cycle concerning the ideas of fluid power. Although the website states that the resource is aimed at American Grade 7 (approximately 12-13 years old) many of the activities and pieces of information are relevant to teachers of post-16 because UK students are unlikely to have met many of the ideas at GCSE.

The webpage includes the formulae that would be useful in the teaching of the concepts of pneumatics and hydraulics including the gas laws, which will be useful background reading for teachers as well as activities for students to complete.

The resource also includes definitions of key words, activity cards and background contexts and applications. Scrolling down there is a list of reasons that hydraulics would be used in engineering systems and a list of definitions of key language. Some of the activity cards (for example worksheet 4, fluid capabilities) could be used to stretch students if there is the desire to better understand the mathematical relationships of fluid power.