The idea is obvious: you don’t have to look out everything first before driving off to the repair site. A key aim is to be compact and self-sufficient. Anyone developing the idea of trenchless partial sewer repairs will sooner or later want a fully equipped maintenance and repair vehicle for use on site. In addition to robots and packers for remote-controlled work inside the sewer, such a vehicle houses a sophisticated infrastructure above ground. Electricity, water, compressed air, flushing unit, fitting materials, an ergonomically configured workstation, system controls, video lab and recreation room – it’s all carried on board, enabling the operators to make top quality repairs and take pleasure in their work. As an example of the Schwalm system we describe below one given solution.
The Workshop on Wheels
Purchase Criteria for a Self-Sufficient Sewer Rehabilitation Vehicle
The rehabilitation vehicle: truck plus box body
Classified by the TÜV vehicle licensing body as a ‘self-driven work machine’, a sewer rehabilitation vehicle is built up as van class model (up to 4.6 tons) or – depending on what is being fitted in – on a 7.5 or 12 tonner. In other words, chassis and driver’s cab come from the truck manufacturer. You thus have the base. Based on individual specifications, the workshop then gets built into a walk-in box-like attachment, simply called a ‘box’ in the trade. Ancillary units in the area under the floor add further to the special vehicle.
Step-by-step to a bespoke client solution
Step 1: Basic questions
There is no standard sewer rehabilitation vehicle. Three questions to be asked before doing anything else help to achieve a sensible balance between equipment level and cost-efficiency: 1. Where is the vehicle going to be used? 2. What precisely is to be done with it? 3. What is the most it can cost? For example: anyone who wants to be able to manoeuvre around the old-town streets of Istanbul or Locarno needs a small, nimble vehicle. But size is not all. To be sure of delivering quality work the vehicle also needs to be adequately equipped. If you have less than the necessary minimum, a botch job is sadly all you can do. Yet it is also appropriate here to ask yourself the opposite: What level of equipment would be excessive?
Step 2: Layout and planning
At first it’s very easy. Client and advisor sit down together and produce some initial basic designs using pencil and paper. A specifications list is drawn up. It is only once things have become a bit more concrete that CAD planning takes it turn. Vehicle design and equipment now take shape in 3D. Particular importance is paid here to the ergonomic configuration of the working area. Safe and non-tiring work in a clean and pleasant atmosphere boosts both quality and motivation. There is even a toilet and a place to wash on board. After all, sewer rehabilitation is not dirty work but a top-class craft!
Step 3: Build
The inside of the box is split into a workshop area and a separated control room for video inspection and documentation and robot control. There is no modular standard for fitting out a vehicle box. It is done precisely to the client’s specification. Be it ancillary units, workshop equipment, working surfaces, furnishings or design – everything is fitted in with millimetre-precision, working from the control room towards the back. Everything is fixed firmly in place so it can’t shift about. Drawers and cupboards are lockable. Fully equipped, such a vehicle includes robots for any inspection and repair work, plus packers for short lining. On top of this comes IT equipment and the control panel for the robotics. Fitting materials such as glass-fibre mats, felt caps and special resins are neatly stored and kept readily to hand on board. The supply units in detail: water supply (up to 1,500 litres); high-pressure pump with 140 bar of working pressure and a capacity of 120 litres per minute; compressor with a capacity of 3 to 6m³ per minute; 220V electricity supply with 8-kilowatt continuous output based on an independent diesel generator. In terms of cost in euros special vehicles of this sort are in the six-figure bracket. The lead-time from placing an order until delivery is around seven to nine months. This takes into account what are now the truck manufacturers’ usual delivery periods of up to six months.
Anyone looking to buy a special vehicle for sewer maintenance and repairs should have a clear idea of precisely what they want: What do I want to do with it? What local factors need taking into account? What capital expenditure am I going to face at the minimum? A well fitted out rehabilitation vehicle helps to save time, money and nerves. It is worth striving to be largely self-sufficient in the field in order to provide work of the best possible quality.
Published in BI Umweltbau, June 2007