SAFETY New NESTRO ®
SAFETY New NESTRO ® dedusters NE J The development of this new generation of dedusters from NESTRO ® Lufttechnik GmbH, Germany, sets a new standard for the industry: This is the first series of dedusters equipped with IE5 reluctance motors and frequency converters. Users can save up to 22 % energy costs compared to those using IE3 motors. In this way, the Thuringian company makes a significant contribution to climate protection and at the same time saves the user money. The development of the mobile NESTRO ® dedusters type NE J in the well-established performance classes 200, 250, 300 and 350 for indoor installation is based on decades of company experience in woodworking, in device technology and in the technology of highly efficient fans. The use of our clean air dedusters for the extraction of various materials pays off cost-wise for small and medium-sized companies in many industries. The NE J verifiably saves • investment costs through installation close to the machine using only short pipeline routes with overall low line resistances • operating costs thanks to the frequency-controlled IE5 reluctance motor (efficiency above 90 %) • heating costs through circulating air operation without heat loss, because the filter material guarantees a residual dust content of < 0.1 mg/ m³ - cleaner than the outdoor air • maintenance costs through an intelligent, certified automatic fire extinguishing system without the use of water or dry chemicals • installation and base costs as a mobile plugand-play device (only power and compressedair connection plus junction of the pipeline required) The construction guarantees optimal extraction with the integrated, proven clean gas technology featuring 100 % dust tightness and with constant target / actual value comparison of the negative pressure needed by the processing machines. The fan is mounted after the filter unit. The clean gas fan does not transport any material. The new design offers for the user four different disposal options using four alternative substructures, which can also be converted at any time: for dust bin(s), for briquetting presses NBP, for separator locks NZRS or for the 800 l norm container common in Switzerland. All mobile bins as well as the feed hoppers for the other three options are equipped with a site glass. In close cooperation with one of the leading German suppliers of so-called reluctance highefficiency motors, NESTRO ® Lufttechnik GmbH is the first manufacturer worldwide to offer dedusters with permanently frequency-controlled, quieter IE5 motors as standard. The frequency converter ensures that the motor always runs at the optimal operating point. At the same time, we have optimized the entire fan geometry over several development stages for precisely this kind of motor. The new NE J achieves the lowest energy consumption per power unit, improves reliability and service life and significantly reduces noise emissions. Exhaust air sound insulation using silencers is integrated in the clean gas area. This makes the NE J one of the quietest devices on the market. Optionally, the entire fan room can be additionally soundproofed. Thanks to a new modular design, the plugand-play devices are more compact and more flexible to use as the previous version and unbeatable in price/performance ratio. The dedusters can, for example, be delivered in segmented parts for narrow passage-ways to be assembled right on site. They are now also suitable for shipping in standard sea containers. The NE J performance classes 200 up to 350 with an operating volume flow of up to 9,500 m³/h have proven themselves and cover the range of applications with more than only one processing machine perfectly. The new generation NE J has an automatic fire extinguishing system starting with performance class 250 certified by the independent fire safety competence centre MPA, Dresden, using a hermetic oxygen seal (fire protection flap). In this way, a fire that arises due to, for example, an ignition source input is immediately suffocated. The blowin box as an expansion space with a backflow flap offers additional functional reliability. In the case of heat dissipation the fire protection flap is closed pneumatically supported and the fan is turned off. Due to the missing negative pressure the backflow flap also closes, the hermetic oxygen seal is established. This function is also maintained in a zeropotential condition. There is no need to use water or dry chemicals to extinguish the fire – this would destroy the whole device. This also saves the user the mandatory periodic replacement of a powder extinguisher. The need for spark detection and extinguishing is also omitted with all of our standard designs due to the low volume of raw gas. Like their preceding models the dedusters NE J have a material pre-separation. This means that dust and sawdust do not hit the filter bags directly. The construction design creates a cross flow underneath the filter bags, which prevents dust and sawdust from being swirled up from the bins or the hopper. Cleaning always takes place after the end of operation by means of compressed air pulses, in the so-called JET process. It is known to be quick, thorough and gentle and leads to a longer service life of the filter material. NESTRO ® has also included an efficient, high-quality air compressor specifically for this application in its product range - users can get everything from one source. All dedusters are approved for indoor installation. At the Research Association for Applied System Safety and Occupational Medicine (Forschungsgesellschaft für angewandte Systemsicherheit und Arbeitsmedizin, short FSA), Mannheim, the new series has also passed the mandatory explosion pressure test and is certified accordingly. Thanks to the FSA certified antistatic filter bags made of polyester needle felt, a residual dust content of less than 0.1 mg/m³ is guaranteed. If there is no space indoors the compact device can also be set up outside, e.g. with a return air duct back to the inside. Here NESTRO ® offers a summer / winter switch for the regulated supply of fresh air for additional comfort. The construction corresponds to the EU standard DIN EN 16770 for dust and sawdust up to dust explosion class St1. With the NESTRO ® -LOGIC control in 32 languages for the automatic fan start at machine start – up up to 8 processing machines can be recognized and the associated gate valves can be controlled as standard via potential-free contacts or spools. So NESTRO ® has an answer to the ongoing trend for more machinery run by the same set of operators. The main control for briquetting press NBP or separator lock NZRS is integrated with the according disposal option in the switchboard cabinet of the deduster – there is only one operating unit for two machines. A wired touch panel terminal with an integrated emergency stop unique within the industry gives the user optimal freedom of movement around the deduster in terms of operation and data analysis. The deduster can be parameterized and operated via the 7“ colour touch panel (switches and indicator lights are no longer necessary). Energy data can be analysed, and commissioning can also take place directly at the processing machines thanks to WLAN. A frequency converter is installed as standard and ensures high energy efficiency at every load level. www.nestro.de 22 No. 4 • October 2021
SAFETY Early and central fire gas detection GSMX-P: Fire gas detection in filter systems The handling of bulk solids poses many challenges. One of these challenges is the enormous amount of dust that is created by conveying and processing the different products. In order not to unnecessarily strain the process and employees on site and to expose them to risks, these enormous amounts of dust get extracted. This is the first step in the direction of fire and explosion protection, because dust clouds of flammable powders in the right mixture ratio to oxygen always represent a great danger. Despite accurate dedusting of the machines, there is still a high fire risk with corresponding bulk goods e.g. through glowing embers transported into the process or self-ignition of the product. So how can this risk be contained? Filter systems represent a central point in most industrial systems because the air extracted from the various machines is usually bundled and guided through a pipe / exhaust duct after the filter elements. Precise monitoring of fire gases within this pipeline enables fire incidents to be detected at an early stage not only in the filter but in all connected machines and system parts. When do which fire gases arise? Combustion (Fire) gases develop before smoke or flames can be recognized. Depending on the bulk material, certain fire gases arise earlier, later or only to a limited extent. In order to cover exactly this point, REMBE relies not only on the measurement of carbon monoxide (CO) but also on hydrogen (H2), hydrocarbons (HC) and nitrogen oxides (Nox). In this way, monitoring can be set flexibly and precisely to process and material. Advantage of a GSMX-P fire gas monitoring system: Fires usually develop over a long period of time. Nevertheless, many systems detect too late. Temperature rises in the exhaust air can only be detected very late by means of temperature sensors and conventional smoke detectors are too sluggish and dust-prone for use under industrial conditions due to their functioning. By the time the smoke concentrations can be detected, a fire has usually already spread too much. In contrast to other systems, the GSMX-P follows the approach of detecting the fire gases in the formation phase and thus does not have to wait for strong smoke concentrations or late temperature increases. If the gas concentrations deviate even slightly from the target state, the GSMX-P already gives a first alarm. Depending on the process conditions, >100g hot product is sufficient to represent a reproducible detection. Phases if fire development How does the GSMX-P work? The GSMX-P fire gas detector monitors the entire cross-section of the clean gas / ventilation line. For this purpose, it is attached to the line in a separate housing. Two pipes protruding into the clean gas / ventilation line generate continuous air extraction over the entire cross-section using the Venturi principle. The design not only enables representative and reproducible monitoring, but also dispenses with further electrical aids such as pumps or fans. GSMX-P design Where is such system used? Almost every process in every industry can be monitored with a GSMX-P in a filter. Because it is a complex system for monitoring multiple gas components, factors such as the following are considered: • Air flow rate m³ / h • Flow velocity and pipe diameter • The amount of dust in the air • Bulk goods (fire and explosion parameters) The sensor is installed in the process and gets used to the process and the conditions in the first step. This makes it possible to create an exact picture of the conventional gas concentrations to then find the optimal limit value for each application. This is usually just above the conventional concentrations in order to detect even the smallest deviations and to prevent a fire. www.rembe.de No. 4 • October 2021 23
