The challenge: to build a machine capable of demolishing parts of a disused power station.
Each team must build a machine capable of destroying some industrial outbuildings at a disused power station in Norwich. No explosives can be used, but battering rams, tow cables, hydraulically operated arms and so on can be. Each team can use more than one machine or approach. The winners are whoever flattens their buildings first.
Chris 'Low Dog' Ryan, Jamie 'Jimbob' Pardoe and Danny Harding are a group of 20-something surfers from St Ives, Cornwall, who have known each other for ten years. Extrovert Chris is the eldest and the team captain; lateral-thinking, methodical Jamie is the brains of the team; and Danny is the grafter with the welding torch permanently to hand.
John 'Spike' Hanson and brothers Andy and 'Big John' Middleton make up this team of hard-working North Yorkshire men. Andy and John have known Spike for 20 years through their shared interest in motorbikes. Andy is the team captain, with a passion for horses and Land Rovers, John loves anything to do with submarines and motorbikes, and Spike can build anything from trikes to planes: 'There’s nowt we can’t build.' They combine know-how, muscle and true Yorkshire grit. But will it be enough to win?
Peter Cracknell (expert for the Beach Boys) is a civil structural engineer from the multinational engineering firm Ove Arup.
Steve Garfirth (expert for Chaos Crew) is a product specialist in hydraulic excavators, working for Liebherr-GB Ltd.
Steve Jack (consultant) is the demolition project manager for National Power.
John Roberts is the president for the Institution of Structural Engineers and the consultant behind the London Eye ferris wheel.
This competition becomes a battle of the ages: medieval versus modern.
The Beach Boys opt for the low-tech approach – a battering ram. For the base, they employ the carcass of an orange camper van. The first major problem is removing its roof. The answer: a length of chain and the quad bike. Robert and Cathy look on in horror as the boys maul the ex-pride and joy of an anonymous caravan fan – the roof comes flying off in one go!
On the camper van base, they erect a couple of steel A-frames to support the ram itself. For this, they scavenge an old metal gas pipe and, to give it weight and strength, wrap it in chain.
The benefit of their approach is that there are few moving parts and so, in theory at least, less to go wrong. It is also a relatively simple build from an engineering point of view, and accordingly they are the only team so far in the history of Scrapheap Challenge to finish before time is called!
This is countered by the fact that the solution Chris and the boys have come up with derives all its bashing might from them – that is, it is human-powered. For pure brawn, the burly team next door outclasses them.
Jamie – who previously invented The Drum, a mechanical surfing apparatus made from a washing machine – adds the crucial aiming device that allows the ram to be adjusted left or right without moving the camper van underneath. However, Chris has some reservations about the quality of his own welding …
In Spike, the Chaos Crew have a secret weapon – they call him the 'Fastest Welder in the West' and he may just be the best welder ever to appear on the programme. Spike is your typical 'white van man' and, appropriately, the team opt for a Transit as the base of their marvellous mechanical monster. What they intend to do is build a mini JCB in a day. This is, of course, no mean feat. It actually involves two distinct builds, which the Chaos Crew amazingly manage to pull together in the nick of time.
The first part is the heavy engineering - creating the arm itself. Some seriously weighty metal is scavenged, and after some hard graft and one potentially disastrous fire on set, it is finally ready to be married to its hydraulic operating system.
This is the second part of the Chaos Crew's plan and is where brainpower meets brawn. Hydraulics, which is a powerful but extremely complex solution (see Scrapheap science), have always put the fear of Robert into most Scrapheap teams. Here, the plan is to use the complicated pressure-tight system to demolish the course with pinpoint accuracy.
The Crew manage to purloin the pump, levers and rams from an old army trench digger on the heap, and so set to work on their brave quest for engineering nirvana. Their approach is not without drama, however. With just minutes to go, they test their monster and nothing happens. With time running out, they bleed the mechanism and roust an air lock. As the monster lurches to life and heads straight towards Robert, he is heard to remark: 'That's the scariest thing that's ever happened to me!'
The Chaos Crew are determined to fare better with their hydraulics than the ill-fated Bodgers in last year's walking machine final. But if wishes were horses …
The imposing bulk of the Norwich power station looms over the teams as they line up at the start of the race. There's still time for a little horse play: Jamie of the Beach Boys allows himself to be picked up by the jaws of the Chaos Crew's metal monster and poses for the cameras.
Soon the race is under way. Each team has to tackle three structures: a set of garages, a pump house and a blast wall. The first machine to 'eat' its half of a structure gets to race to the second and so on to the finish.
The Beach Boys don't make much of an impression on the garages at first. As the Chaos Crew arrive, their hulking beast takes a giant bite out of the wall and it looks like they'll make mincemeat of the ram. After a few more bites, however, disaster strikes: a weld holding the support for the munching arm gives way and the arm comes crashing down on top of the machine, destroying a camera in the process. With the renowned Spike on the job, this is the last thing anyone expects to fail. It's all hands on deck with the welder as the Chaos Crew try to claw back the lead.
Meanwhile, the Beach Boys have finished with the garages and moved on to the second target – the pump house. By now, they have a rhythm going and have set to work in earnest. Just as the Chaos Crew finish their repairs and it looks as if they could catch up, a second disaster strikes: the Transit's radiator is holed. If it is to run at anything like full power, Cathy must help by lugging over a traffic cone full of water, which she gradually pours into the radiator.
The metal muncher is limping badly now. As the Chaos Crew finally demolish the pump house and round the corner to the blast wall, they find to their horror that the Beach Boys are almost done.
In the end, it is the Beach Boys who take the trophy, but only by the skin of their teeth. Had their welding stood up to the hype, the Chaos Crew would have been invincible.
KISS.
Later in the series, we will meet the NERDS, an American team whose Scrapheap rationale is: KISS – Keep It Simple, Stupid. It looks as if their acronym suits this first show of the new series, too, with the medieval triumphing over the modern.
The challenge: to build a machine capable of demolishing parts of the outbuildings of a disused power station. While the Chaos Crew opted for a hydraulic brick crusher, the Beach Boys tried a medieval-style battering ram.
Pros.
Cons.
Pros.
Cons.
Hydraulic power - an alternative to brute force?
A fluid, usually water or oil, is used to transmit power from a pump to a hydraulic motor or a hydraulic ram (piston). Because liquids are nearly incompressible, large pressures can be built up to exert very great force within a hydraulic ram.
How has hydraulic power developed?
In 1795, the British engineer Joseph Bramah invented the hydraulic press using the principle of hydraulic power, and then he came up with hydraulic power transmission, using a pump and motor. During the 19th century, hydraulic power was used for cranes, dock gates, swing-bridges and lifts. Perhaps the most famous example is the hydraulically operated Tower Bridge in London.
Today hydraulic power is used in farm tractors to control ploughs and in earth-moving equipment, presses, winches and aircraft main control surfaces, landing gear and brakes. Most car braking systems are hydraulic, too.
What are hydraulic rams and pistons?
A hydraulic ram consists of a cylinder with a piston inside. One end of the piston is attached to a rod that moves – pushing, lifting, pressing. Inside the ram, the end of the piston to which the rod is attached is called the 'rod side' and the opposite side is called the 'piston side'.
The surface area of the 'piston side' is always greater than the 'rod side' because the rod itself takes up some space. It is therefore the 'piston side' that exerts the greater force for a given pressure. The larger the surface area of the 'piston side', the greater the force the ram can exert. This pressure is provided by a hydraulic pump that has a much smaller surface area than the ram.
The best example of all this is the car jack. This consists of two cylinder pistons: one, the 'pump', with a relatively small diameter; and the other, the 'lift ram', with a relatively large diameter. Pumping the pump causes the lift ram to rise slowly and with much more force than the pump, and it will travel a much shorter distance. Nevertheless, with the expenditure of very little effort, a comparatively weak person can eventually jack up a very heavy car.
If the surface area of the 'ram piston' is ten times greater than the surface area of the 'pump piston', the distance travelled by the ram will be ten times less, but it will produce ten times more force.
Pascal's Principle provides a simple formula – force (F) is equal to the area of a piston (A) multiplied by the pressure (P):
F = A x P.
For example, if a ram with a diameter of 25mm has to lift 1 metric tonne (1000kg or 2205lb), the internal pressure on the piston will have to be 200bar (20,000,000Pa or 2900lb per square inch). If the internal diameter of the ram cylinder (and thus the surface area of the ram piston) increases, the pressure required to support the same load will be less. For instance, if you quadruple the diameter of the ram cylinder to 100mm, the required pressure within it drops to only 12.5bar (1,250,000Pa or about 180lb per square inch) to support the same 1 metric tonne load – the relationship between pressure and area increasing exponentially rather than directly.
Which rams are best?
This depends on the requirement. A fast-acting ram, with a comparatively smaller diameter, would be less powerful than a powerful ram with a larger diameter, which would move relatively slowly.
What's a hydraulic circuit?
This consists of a hydraulic pump that sucks oil from a storage tank and pumps it around a series of pipes, control levers and rams or motors, finally returning back to the oil tank to begin again.
In a simple circuit where there is one ram controlled by a single control lever, if the lever is not being used, the oil is pumped straight through the control valve back to the tank. If the operator moves the control lever in one direction, the valve inside diverts the oil to the ram, thus pushing the ram in a given direction. The oil on the opposite side of the ram piston will then be displaced back into the tank. The same thing happens in the other direction if the operator pulls the lever back the other way.
Is hydraulic pressure efficient?
Typically only 60–70%. In comparison, a car engine is nearly 90% efficient.
You can find out more from the Scrapheap Challenge advisers about the battering ram and hydraulic demolition solutions.
1 The task.
To demolish a section of three different brick buildings at the disused National Power plant at Norwich. The walls are formed in good quality brickwork with sand-cement mortar, and have a maximum height of 3 metres. The walls are to be demolished down to 1m above ground. Challenges 1 & 3 are free-standing walls, having had the existing roofs of asbestos and supporting steelwork removed by others. Challenge 2 is a small pumphouse built as a three-sided lean-to against a massive reinforced concrete structure. It has an asphalt roof on wood-wool planks supported on a central RSJ.
2.1 Concept.
I have devised a battering ram – the Plunger – which will be suspended from a steel framework mounted on a base vehicle such as a Land Rover, Ford Transit, etc. (i.e. a vehicle with a solid chassis). The motive power for the demolition will be 'brute force' from the team of four men (three young enthusiastic surf-boarders and one middle-aged consulting engineer), with the vehicle engine being used to just move the machine around.
2.2 The machine.
The base vehicle is stripped down to floor 'bed' level, taking care to not cut any of the vital wiring loom. A strong 'base' is constructed to support the 'A' frames, probably using two 'steel cross beam' channel sections welded back down on to the base vehicle. Care is taken to ensure that the base is firmly fixed down on to the vehicle chassis or other strong point. The channels will be 2m long to give a wide base, yet not too large an overhang. (This is within the 2.8m-wide limit set by RDF for road transport. The overall height of the machine is set at 3.95m to fit under the OHE rail crossing at Norwich. RDF must check the overall height of machine + transporter to ensure it complies with road transport regulations.)
The proposed method is to involve the use of a simple hydraulic cracker/crusher tool to demolish a small brick/concrete structure. This proposal is based upon the structure to be demolished as being a single storey building with a 'brick' or 'non-reinforced concrete' structure, with sufficient firm flat surface surrounding area to allow access. For this reason, the built equipment would need to have a working range of 2–3 metres outward and a vertical reach of 4–5m. The equipment arms would consist of two hydraulic arms (similar to the commonly known Hiab device found on the rear of trucks), with a controllable crusher tool that would need to be mounted on the end of the arms.
1 Power source/chassis structure.
The engine needs to have a power rating of 50–100kW power. Preferably this would be a diesel engine as these perform better at a fixed rated speed (rpm) without problems, and also they do not require an electric ignition system. They also generally operate at a lower rpm than a petrol engine, which means that a diesel engine would be more suitable for direct coupling to a hydraulic pump which normally has a flow output specified relative to approximately 1500–2000rpm operating speed.
Proposed materials.
2 Drive couplings.
Engine side: To enable the power of the engine to be transferred to the hydraulic pump, an engine output drive coupling is required that mates to the engine output shaft. Again, if there was a 'scrap' diesel transit available, it should be possible to utilise the output shaft.
Hydraulic pump side: When the hydraulic pump is sourced, a specific coupling for the hydraulic pump input drive shaft is required. This pump coupling could be mated to the engine coupling using general resources on the day such as a chain or gear-drive to a transit van drive shaft or a manufactured linkage direct from the engine output shaft.
Proposed materials.
3 Hydraulic pump.
This item is one of the most critical to the project (the other being the crusher hydraulic ram size). The hydraulic pump is specified by its oil flow output at a given speed. The speed is best matched to the output speed of your power source (i.e. engine shaft drive output). The hydraulic pump is also required to operate at specified maximum working pressure. The aim of the complete exercise is to obtain the required amount of force not only to operate and lift the cracker/crusher tool into the required working position but also, and more importantly, to operate the hydraulic ram that closes the jaws of the crusher tool.
In simple terms, a lower hydraulic pressure needs a larger ram cylinder diameter, and a higher hydraulic pressure could use a smaller ram cylinder diameter in order to exert the same given crushing force at the point of work. There needs to be a balance on these requirements and this has been accounted for in the proposed material list. In general, the available flow for this project could be between 50–150 litres/min., and a working pressure capability of between 230 bar absolute minimum to approximately 300 bar maximum.
Proposed materials.
The absolute minimum requirement would be a fixed flow 50 litres/min. hydraulic gear pump capable of at least 230 bar minimum working pressure.
The hydraulic oil tank is required to hold sufficient oil volume to fill all of the hydraulic rams if in an extended condition. Allowance for the oil within the system and hoses needs to be considered. As the actual rams to be available are not known at this stage, it would suffice to assume each ram for the arm movements would not hold more than approximately 7–10 litres per ram, and the crusher ram approximately 12–15 litres. Therefore, 10 litres x four rams = 40 litres + 1 or 2 crusher rams of 15/30 litres = a possible 70 litres of oil required.
Proposed materials.
5 Equipment structure.
The purpose of the equipment arm is to position the cracker/crusher tool into the required working position to enable it to access the material to be demolished. The basic layout for this equipment is the same as the commonly known 'Hiab' device as found mounted to the rear of some trucks. If such a device was available as 'scrap' within the yard, it would make the complete project much more viable as the majority of the hydraulic rams (see Section 6) would be available as well as the main lifting arm structure. We could, however, construct the actual arms using materials such as 'U section' or 'square section' steel of a suitable size and wall thickness.
Proposed materials.
Alternatively.
6 Hydraulic rams for all arm functions and special hydraulic ram for crusher tool.
The hydraulic ram cylinders are required for the manipulation and movement of the equipment arms. A separate hydraulic ram is required for each function. These functions would be:
Optional additional functions could be:
It can be seen from the above that a minimum of five hydraulic rams may be required to complete the project. This could possibly be reduced to four rams if the ram no. 3 for the swing was able to be operated manually.
Rams 1 to 3 could be sourced from a 'scrap' lifting arm such as the commonly known 'Hiab' device as found mounted to the rear of some trucks. If this was used, the equipment would need the have a working range of 2–3 metres outward and a vertical reach of 3–4m in order to access all the areas for demolition.
Ram 4 would need to be additionally obtained to angle the crusher position correctly.
Ram 5 is very specific to requirement. In order that we may obtain the necessary 'breakout force' to crack/crush materials such as brick/concrete, the hydraulic ram for the actual crushing action needs to have as great a diameter as possible with a stroke length sufficient to allow the crushing tool to complete its movement.
Again, there needs to be a balance on these requirements and this has been accounted for in the proposed material list.
Proposed materials.
7 Hydraulic control valve system with safety relief valves.
As described in section 6, there will be five main control functions. Depending on whether or not a 'scrap' Hiab device is located within the scrapheap, we need to ensure that the correct required control valve gear is available. The control block should have 5–7 available functions. It is possible to use two separate control valve blocks to perform this operation. Each control valve block requires its own integral safety pressure relief valve that is adjustable up to 300 bar or greater.
Proposed materials
8 Hydraulic suction/pressure/return hoses and fittings.
It is, of course, required to connect up all the hydraulic functions to complete a full circuit.
It is, of course, very important that, whatever components you finally specify for use, the fittings at each of the hoses are correctly matched to fit perfectly. In respect of safety issues, it is required that all hoses are manufactured new using the following proposed material list as a guide. It is, of course, not possible to provide specific fitting types or sizes as these hydraulic components are unknown at this time.
Proposed materials.
9 Cracker/crusher tool and special hydraulic ram.
It should be possible to construct a simple brick/concrete cracker/crusher from some lengths of substantial steel. This item would require the use of oxyacetylene cutting equipment and a high-power welding set, including a competent operator. The basic design consists of using lengths of 50mm x 200mm thick steel. The crusher would consist of a triple plate design where the two lower outer plates form the main structure and the centre crusher/shear can be powered by the large diameter hydraulic ram.
Proposed materials.
Special tools.
10 Various general items and certain tools.
Proposed materials.
Proposed tools.
Hydraulics.
home.wxs.nl/~brink494/frm_e.htm
English translation of a Dutch site by Rob van den Brink. Explains the basics of hydraulics and all types of pumps, etc. The English is a little broken but the animations tell all!
Fluid Power Net.
www.fpni.net
Information about and links to worldwide research and industrial activities in the field of fluid power (hydraulics and pneumatics).
Fluid Power Web.
www.fpweb.com
The internet site of the journal Hydraulics and Pneumatics.
The Roman Battering Ram.
www.ukans.edu/history/index/europe/ancient_rome/E/Roman/
Texts/secondary/SMIGRA*/Aries.html
A short article on the ancient Greek and the ancient Roman battering ram (aries), with an illustration.
Battering ram.
www.geo-metricks.com/geo-shop/rt-promo-htm/str/cast-pr/
prbatteram-pr.htm
Simple 3-D model of a battering ram (four views).
Controlled Demolition Group.
www.controlled-demolition.co.uk
UK's biggest demolition company. Lots of information about explosives and demolition, with online digital footage of some of the company's most spectacular moments.
Institution of Structural Engineers.
www.istructe.org.uk
Publications, news and services, including a useful online message board: post your engineering and construction questions or get in touch with someone grappling with the same problem as you. Scrapheap Demolition judge John Roberts is president of the Institution.
Institute of Explosives Engineers.
www.iexpe.org
Information on the institute's aims, organisation and membership, as well as details of forthcoming events. John Faulkner, Scrapheap's special guest, is a member.
Professional Health and Safety Experts.
www.healthandsafety.co.uk
Demolition needs to be safe! This site contains news, information on the Health & Safety Executive and their publications and an online service that promises a prompt response to any health & safety-related problem.
Caterpillar UK.
www.cat.com
Major British firm selling excavating hardware.
Liebherr International.
www.liebherr.com
Major German firm selling hydraulic excavators, construction cranes and other hardware. Scrapheap expert Steve Garfirth works for Liebherr.
National Power.
www.national-power.com
Register on this site to get National Power's information service and press releases e-mailed directly to you. They also produce an e-mail newsletter with the latest developments within the energy industry. Steve Jack, a consultant on demolition for Scrapheap, works for National Power.
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