凸臺提升機的設(shè)計

凸臺提升機的設(shè)計,凸臺提升機的設(shè)計,提升,晉升,設(shè)計 Dave Wolstencroft, Technical Manager, 4B Components, USA, explains how steel web elevator belt&SJ buckets enhance the performance of bucket elevator.WORLD CEMENT May 2005IntroductionDue to the demand for larger capacity, more efficient, and more cost effective elevators to carry industrial products such as cement, 4B components has researched, tested and supplied the industry for the last nine years with an integrated system of steel web belting, SJ buckets and elevator designs for compact industrial elevators.The company has designed, developed and successfully introduced the Polysur Ferro steel reinforced elevator belt system and high capacity Starco Jumbo elevator buckets. These achieve high capacity at a comparatively lower cost than using chain or traditional belting with fabricated buckets.Traditional systemsThe majority of elevators have traditionally been installed with chain. This, however, can be very expensive and has immense maintenance implications after installation.Chain bucket elevators usually have large casing dimensions, cumbersome elevator buckets, and they are pitched apart at quite a distance. Chain operates at a relatively low speed(1.3 m/s), due to frictional and noise problems, which has a net result of limiting the case size. Also, high strength, large construction chain, big motors, etc, are required on chain and bucket elevators. All these factor contribute to an expensive elevator, not only in initial cost but in further maintenance cost, and costly downtime.Large and cumbersome fabricated elevator buckets can also be used with belting. These are a very expensive option like chain, because they also take up a lot of volume within an elevator casing, and fabricated buckets are extremely costly compared to their pressed counterpart. As a result, the casing will also become large and more expensive.SJ and steel web belt alternativeAs an alternative to the established approach, 4B has developed a Ferro steel reinforced belting system, incorporating the unique SJ bucket design.The Starco Jumbo and steel web belting can use multiple rows(one to four rows of three different sizes) of closely spaced, heavy-duty Jumbo seamless steel buckets with a purpose designed steel web system, and a high temperature elevator belt.The elevator belt will wear significantly less than the chain alternative. This is mainly due to the smaller number of moving parts compared to the chain links and sprockets. The chain will experience continual friction between each part, thus causing constant wear, then eventually downtime.The elevator buckets are pressed from 4 mm mild steel and will, therefore,have an extensive lifetime of use. A wearband, welded onto the front edge and sides of the buckets, is an option if the product is particularly abrasive. The buckets are designed to achieve very high capacities through their unique optimum design characteristics, these maximise bucket fill and will ease product release. The buckets are also designed in such a way that they can be spaced at very tight intervals, unlike the traditional system. The buckets can also bu used up to 2.3 m/s on the larger pulley diameters(which is still gravity discharge), which will enable high capacity. This all has a positive effect on the reduction of the casing size.Tables 1 and 2 demonstrate the difference between chain and bucket, and the steel web belt and SJ buckets.High capacity low maintenance system for industrial elevator Compared to traditional chain and bucket elevators, Polysur Ferro steel web belt fitted with Starco Jumbo buckets offers:l Up to double the elevator capacity.l Throughputs up to 1300 thp and over.l Much lower capital investment.l Longer trouble free life.l Reduced maintenance and spares cost.l Opportunity to upgrade capacity of existing elevators.The steel web belt has fewer friction and wear points compared to chain. The elevator belt has a constant operation temperature of 120. With peaks of 150, but also has very thick covers (usually 4 or 5 mm). This helps withstand the rigours of cement and other abrasive industrial products.Due to the construction of the belt, it will have almost no stretch. In the past a fear associated with elevator belts was that the belt would stretch with initial sue. This will not happen with steel web belt, due to the special Ferro E-cords in the warp and weft.4B can offer belt strength up to 2000 KN/m, which well cope with the toughest of applications. The belt is also guaranteed and can last for many years depending on application. All belts come with punched holes on application.A special Allen key head bolt can be used to enable case of use and access into the holes of the belt by using and electric drill with an Allen key bit to screw the bolt through the belt.Case studiesThe company has successfully completed numerous elevator designs. It can offer free engineering design specifying the correct buckets, belting, bolts, case sized, motors, etc, in order that the bucket elevator manufacturers can producethe optimum and most cost-effective elevator. The service can also be offered to the end users, such as cement plants, whereby their existing elevators can be changed over from chain and the capacity increased, even doubled.In one instance an elevator did not reach the anticipated capacity of 180-200 tph and frequently lost buckets due to fixing bolts being pulled through the belt. The belts often mis-aligned, and the casing side was damaged by off-tracking belts.A polysur Ferro belt was fitted for improved tracking. The belt speed and belt strength was increased. The fabricated buckets were replaced by the SJ 370 buckets at a reduced pitch to achieve the desired capacity of a minimum 200 thp (actually calculated as 285 tph ) Figure 3. Retrofit using-T130C belt 4+4 covers, SJ370-250(4 mm thick ) pressed steel buckets and M 1250 Allen key DIN bolts with high temperature resistant locknuts, and a special aluminum clamp.Another example is of an existing chain elevator in Australia that was upgraded from 120 tph cement, to 250 tph by retrofitting and installing one row of SJ470 buckets and using Ferro bet SW1000 4+4. The original 25 m high elevator had chain installed, and it was decided to change over to Ferro belt with SJ buckets to improve the performance and life.