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Controlled toxins in used oil
International News Roll-force m e a s u r e m e n t s y s t e m h a n d l e s high loads A roll force measuring system, the PressductorMillmate, for applications in the aluminium, steel and other metal processing industries, contains load cells which can handle more than five times the equivalent nominal load without any mechanical damage. Overloading up to three times the nominal equivalent load may occur before the load cells have to be re-calibrated. Based upon the Pressductor principle (the magneto-elastic effect), the design of the load cell permits
Computer-aided mould design for rubbers RAPRA Technology is to launch a powerful microcomputerbased flow and cure analysis system for the rubber mould designer. Entitled Fillcalc, the system allows rapid assessment of the feasibility of a design and then the establishment of optimum mould dimensions and operating conditions. Computer-based flow analysis systems have, of course, been available to the plastics industry for some years and have been shown to offer many benefits, including: reduction in the need for costly and time-consuming mould modifications which may result when using traditional design methods; more efficient runner and cavity layouts, leading to fewer rejects and helping to optimise machine and material utilisation; moulded in shear-stress gradients, which subsequently affect product quality, can be minimised. Compared to software for plastics flow analysis, this program has to handle the more complex thermo-rheological properties of rubbers. The relationship between viscosity, shear rate and temperature is more complex in rubbers than in most thermoplastics: other packages have used first-order
Controlled toxins in u s e d oil The quantity of used oil produced in the Federal Republic of Germany every year is in the region of 500 000 tonnes. In recent months, there has been much public discussion of the possible dangers represented by the polychlorinated biphenlys (PCB) present in used oil. PCB in used oil is an environmental problem, since uncontrolled combustion can cause toxic polychlorinated dioxins and furanes to form. While new legislation concerning the elimination of used oils is being discussed, press reports state that stocks at the companies reponsible for the processing of used oil have currently built up some 100 000 tonnes of material contaminated with PCB. Degussa A G has developed a process for the treatment of used oil with metallic sodium in finely dispersed form. This makes it possible to separate organic compounds and other
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large deformation and gives good mechanical tolerances; this effect means that the mechanical stress influences the magnetic properties of the material. A microprocessor-based control unit is used for signal processing, which is analogue, while all monitoring and control of the analogue signal is digital. A carrier-frequency system is used for signal transmission, which is consequently insensitive to interference. The carder frequency selected is such that the system can measure very fast roll force changes: the system has a step response time of I ms. ASEA: S-721 83 Vasteras, Sweden. Tel: 021:10 00 00.
models for this, whereas Fillcalc uses a curved relationship between the logarithms of viscosity and shear rate and differently shaped curves for different temperatures. As well as ensuring that the mould will fill efficiently, the program also calculates the cure time and the temperature profile within the mould and computes, for each section of the mould, the degree of scorch during flow, pressure drop and material temperatures. The program is divided into modules: the first two modules are for the input of material and mould data, whilst the second two undertake the flow and cure calculations and the remaining are for manipulating results. The flow analysis calculations use numerical methods which involve both transverse and axial meshes. Techniques developed at RAPRA maintain a high degree of accuracy with comparatively small number of mesh points. Cure calculations take place both during flow analysis to warn of premature scorch and in the cure analysis module. Heat history accumulated during flow forms the input to the cure module, which determines the time for gate and cavity regions to reach a user-defined minimum level of cure. The price of Fillcalc is £5000, which includes full documentation. R A P R A Technology: Shawbury, Shrewsbury, Shropshire SY4 4NIL Tel: Shawbury (0939) 250383.
impurities out of the oil. The most recent experiments, now confirmed by, an independent research institute, indicate that the process also reliably destroys the PCB constituents in the used oil, so that the limit values of not more than 10 ppm of PCB can be complied with in the qe-raffinate. The environmentally hazardous toxins are destroyed by encouraging the chlorine they contain to combine with the finely distributed sodium and form sodium chloride. After this, fractional distillation converts up to 80% of the detoxified and purified used oils into high-quality oils. The residues are pyrolysed to obtain the necessary heat energy for the process to be performed. Even if the used oil contains larger quantities of the PCB, it can still be processed by the Degussa method without any environmental hazard occuring. Degussa: Postfach 110533, D-6000 Frankfurt 11, Federal Republic of Germany.
MATERIALS & DESIGN Vol 9 No. 1 JANUARY/FEBRUARY 1988
Computer-aided mould design for rubbers RAPRA Technology is to launch a powerful microcomputerbased flow and cure analysis system for the rubber mould designer. Entitled Fillcalc, the system allows rapid assessment of the feasibility of a design and then the establishment of optimum mould dimensions and operating conditions. Computer-based flow analysis systems have, of course, been available to the plastics industry for some years and have been shown to offer many benefits, including: reduction in the need for costly and time-consuming mould modifications which may result when using traditional design methods; more efficient runner and cavity layouts, leading to fewer rejects and helping to optimise machine and material utilisation; moulded in shear-stress gradients, which subsequently affect product quality, can be minimised. Compared to software for plastics flow analysis, this program has to handle the more complex thermo-rheological properties of rubbers. The relationship between viscosity, shear rate and temperature is more complex in rubbers than in most thermoplastics: other packages have used first-order
Controlled toxins in u s e d oil The quantity of used oil produced in the Federal Republic of Germany every year is in the region of 500 000 tonnes. In recent months, there has been much public discussion of the possible dangers represented by the polychlorinated biphenlys (PCB) present in used oil. PCB in used oil is an environmental problem, since uncontrolled combustion can cause toxic polychlorinated dioxins and furanes to form. While new legislation concerning the elimination of used oils is being discussed, press reports state that stocks at the companies reponsible for the processing of used oil have currently built up some 100 000 tonnes of material contaminated with PCB. Degussa A G has developed a process for the treatment of used oil with metallic sodium in finely dispersed form. This makes it possible to separate organic compounds and other
52
large deformation and gives good mechanical tolerances; this effect means that the mechanical stress influences the magnetic properties of the material. A microprocessor-based control unit is used for signal processing, which is analogue, while all monitoring and control of the analogue signal is digital. A carrier-frequency system is used for signal transmission, which is consequently insensitive to interference. The carder frequency selected is such that the system can measure very fast roll force changes: the system has a step response time of I ms. ASEA: S-721 83 Vasteras, Sweden. Tel: 021:10 00 00.
models for this, whereas Fillcalc uses a curved relationship between the logarithms of viscosity and shear rate and differently shaped curves for different temperatures. As well as ensuring that the mould will fill efficiently, the program also calculates the cure time and the temperature profile within the mould and computes, for each section of the mould, the degree of scorch during flow, pressure drop and material temperatures. The program is divided into modules: the first two modules are for the input of material and mould data, whilst the second two undertake the flow and cure calculations and the remaining are for manipulating results. The flow analysis calculations use numerical methods which involve both transverse and axial meshes. Techniques developed at RAPRA maintain a high degree of accuracy with comparatively small number of mesh points. Cure calculations take place both during flow analysis to warn of premature scorch and in the cure analysis module. Heat history accumulated during flow forms the input to the cure module, which determines the time for gate and cavity regions to reach a user-defined minimum level of cure. The price of Fillcalc is £5000, which includes full documentation. R A P R A Technology: Shawbury, Shrewsbury, Shropshire SY4 4NIL Tel: Shawbury (0939) 250383.
impurities out of the oil. The most recent experiments, now confirmed by, an independent research institute, indicate that the process also reliably destroys the PCB constituents in the used oil, so that the limit values of not more than 10 ppm of PCB can be complied with in the qe-raffinate. The environmentally hazardous toxins are destroyed by encouraging the chlorine they contain to combine with the finely distributed sodium and form sodium chloride. After this, fractional distillation converts up to 80% of the detoxified and purified used oils into high-quality oils. The residues are pyrolysed to obtain the necessary heat energy for the process to be performed. Even if the used oil contains larger quantities of the PCB, it can still be processed by the Degussa method without any environmental hazard occuring. Degussa: Postfach 110533, D-6000 Frankfurt 11, Federal Republic of Germany.
MATERIALS & DESIGN Vol 9 No. 1 JANUARY/FEBRUARY 1988