// CONTROL TECHNOLOGY
New products
Belt-alignment switches are integrated in many bulk goods conveyors as important and easy-to-install monitoring systems. A roller connected to a switch sweeps the conveyor belt. If the conveyor belt is off-track, the roller will be moved sideways, actuating the switching element of the alignment switch. A warning signal can then be transmitted to a control room, for example; or the belt can be switched off, the damage caused to a conveyor system by skewing being considerable.
Our ZS 73 SR series of belt-alignment switches fulfils this task reliably, even in rough conditions. A metal enclosure protects the switching element from mechanical influences, while the belt-alignment roller, made of 1.4104 stainless steel, is resistant to both corrosion and chemicals. Users can already choose between push-button or key release options, and at the Hanover Fair 2009 steute will be presenting another new variant: now the ZS 73 SR is also available with staggered contacts.
The command device of type BF 72 RS SW presented by steute as a new product, looks like a conventional command switch used in the building automation and industry, e. g. to open doors and flaps, to switch on fans or to start machines.
However there is an important difference: this command switch doesn't need any external energy supply nor a cable for the signal transmission. Thus it can easily be mounted on the surface irrespective of cable ducts and power sources. And if it has to be placed elsewhere, it can be done in a very short time.
This is possible by means of the innovative radio technology steute already uses at other switch series. Here a radio protocol is applied that works with just a little amount of energy, nevertheless it is very stable even in an unfavourable environment, since it transmits with very short pulses on the 863,3 MHz band.
In the extraction industry, in power stations, as well as in waste management, oversized conveyor systems are often used to transport raw materials or finished products in bulk. Sometimes a conveyor belt can travel between its rollers off-centre, for example if it has been loaded unevenly. If this error remains undetected, the result can be standstill, meaning a plant shutdown and considerable repair problems: a belt loaded with 10 or 50 tons of material is very difficult to realign with accuracy.
In order to prevent this from happening, all that is required is a relatively unimposing switching device – a so-called belt alignment switch. As a specialist for complex switchgear, steute already sells this type of switch, but we are currently expanding our product range to include a new model which has been developed especially for rough environments.
The new pull-wire emergency switches with swing arms currently being presented by steute have been especially developed for rough conditions. The enclosure, made out of fibreglass-reinforced Duroplast, is carefully encapsulated, meaning that neither moisture nor abrasive dusts can penetrate to the interior of the enclosure. Its metal components are made out of stainless red brass or steel.
In addition, the ZS 90 S is insensitive to frequent bumps and knocks. Since it can be used in temperatures ranging from -40 to +80°C, it is also suited to outdoor applications, e.g. in conveyor systems for quarries and sand pits.
The ZS 90 S enables operators to activate the emergency-stop function over a distance of up to 2 x 50 metres. Upon activation the switch triggers an immediate halt of the plant. The swing arm engages in the emergency-stop position and cannot be disengaged again until a lever in the enclosure is actuated.
Pull-Wire Switches with Additional Contacts and High Protection Class
Machinery and plant manufacturers who need a solid, reliable emergency pull-wire, e. g. for cramped mounting areas and small machines, are well-advised to opt for the ZS 71. This device offers not only a very compact enclosure of just 105 mm, but also a high degree of reliability and safety.
The standard version includes the monitoring of wire pulls and breaks: if the wire, which may extend to 20 m, should break or be dismantled, the switch will automatically assume the safe latched status. The emergency-stop function is unlatched by means of a push button.
Repeater for Innovative Radio Switches
Self-sufficient switchgear devices developed by steute are now applied in many areas of control technology and building automation. The switching signal is transmitted via radio and the necessary energy is generated from the ambient surroundings according to the »energy harvesting« principle – e. g. via a miniaturised solar cell with an integrated energy supply or via an electrodynamic energy generator converting the plunger movement into electrical energy. This steute product range is continually expanding. Self-sufficient position, foot, pull-wire and door handle switches are all currently available. The extraordinarily fail-safe signal achieves a transmission range of 300 m outdoors and 30 m in closed rooms – better than that provided by comparable radio standards.
Without Obstacles: Wireless Foot Switches
Everyone who uses foot switches knows the problem: the cable gets in your way and can constitute a dangerous obstacle – or the cable gets stuck, meaning that the switch cannot be positioned as you would like it to.
With the new KF F foot switch these problems become a thing of the past. Radio transmission rendering cables superfluous and even the power supply is wireless, provided by a durable lithium-ion cell.
In Protection Class IP 66 and Corrosion-Resistant Design
Offshore technology and the offshore industry make extremely high demands on switchgear. The devices have to meet the highest available requirements and achieve the highest protection class to ensure that no splashing water can seep inside the enclosure. Moreover, maximum corrosion protection has to be guaranteed. On offshore platforms and tankships, explosion protection plays a very important role.
steute series ES/EM 95 and series EEx 95 position switches with separate wiring compartments are well suited to these extreme conditions. They are designed to meet protection class IP 66 and are also saltwater-proof, with solid enclosures made of glass fibre reinforced thermoplastic and screws made of stainless steel.
