Flat belt 600x3 0/0 BKNL-65 GOST 20-85

Flat Elevator Belt (Rubber-Fabric Conveyor Belt)

The flat elevator belt is the main traction and load-bearing component of vertical bucket elevators. The product is designed to transmit traction force from the drive pulley and move bulk materials using attached working elements - buckets. It is widely used in grain cleaning complexes (ZAV, KZS type), grain dryers, and agricultural processing lines.

In technical documentation and spare parts catalogs for Soviet-standard equipment, this assembly is often labeled as "flat rubber-fabric drive belt" (according to GOST 23831-79), while under more modern nomenclature (GOST 20-85), the product is classified as a "conveyor belt". From the perspective of practical operation on bucket elevators, these concepts are identical and denote a smooth multi-ply canvas that accepts the main tensile load.

Construction and Materials of the Elevator Belt

The basis of the elevator belt constitutes a carcass formed from a specific number of fabric plies (layers). The plies are bonded together by rubber interlayers, ensuring the structural integrity and flexibility of the construction. Previously, the standard for NC-type elevators was belts based on B-820 fabric ("belting" - cotton duck), but later, belts based on BKNL-65 fabric became the standard for equipment completion and repair. This is a composite material where the warp thread consists of polyester (Lavsan) and cotton. The use of combined BKNL-65 fabric in the elevator belt instead of pure cotton is due to improved physical and mechanical characteristics:

1. Moisture resistance Synthetic fibers prevent the rotting processes of the carcass, which is a critical factor during the seasonal conservation of ZAV complexes and operation in high-humidity conditions.

2. Low relative elongation Polyester cord has a higher modulus of elasticity, so such a belt stretches significantly less under load compared to cotton belting. This significantly reduced the "endless" stretching of the belt during operation, thanks to which the standard travel of the take-up screws lasts for a long period, sparing the mechanic the need to frequently stop the elevator to shorten (re-splice) the belt.

The choice of a specific belt size depends on the elevator's capacity and shaft height. These parameters determine the necessary belt width and the number of fabric plies (layers), which ensure the required safety margin for tensile strength.

Sizes and Application of Belts on Elevators (NC, ZAV)

Below is a reference table corresponding belt width and number of plies (layers) to the most common models of elevator equipment.

When selecting a belt for repairing non-standard or imported equipment, keep in mind that the belt width should be 20-25 mm wider than the bucket width, but narrower than the pulley width, to avoid rubbing the edges against the casing walls during centering and possible operational belt tracking deviations.

Installation and Splicing Features of the Elevator Belt

Unlike horizontal conveyors, where hot or cold vulcanization (gluing) is often used, mechanical fastening remains the only acceptable standard for vertical elevator belts. This is due to the specifics of elevator operation:

1. Maintainability A mechanical splice allows for quickly opening the loop to shorten the belt (taking up elongation) or replace a damaged section directly in the shaft, without involving third-party contractors.

2. Reliability in dusty conditions Grain and flour dust makes quality vulcanization in "field" conditions practically impossible, whereas a bolted connection guarantees tensile strength regardless of surface contamination.

Splicing Methods

The classic method for NC and ZAV type elevators is the "lap joint" (overlap splice). In this case, the belt ends are superimposed on each other (overlapping by 3-5 bucket pitches), and the back wall of the bucket itself acts as the clamping plate. Fixation is performed using the same elevator bolts used throughout the belt, but the main requirement here is that the bolt length must be sufficient to reliably grip the double thickness of the webbing. For more powerful and high-speed elevators, as well as when using belts thicker than 6-8 plies, it is recommended to use special mechanical belt fasteners. They allow joining the belt via a "butt joint," which eliminates the imbalance and bumping that inevitably occurs when the thickened section (overlap) passes over the drive pulley.

Important Warning: BKNL fabric, like any multi-ply structure, tends to "settle" under load. Therefore, a critically important stage of installation is the retightening of all bolted connections after the first hours of elevator operation. Ignoring this procedure leads to loosening of the fasteners and elongation of the bolt holes, which substantially reduces the service life of the assembly. However, whatever splicing technology you choose, the manufacturing capabilities of "Zavod Moroza" allow for a turnkey order completion - we offer both the belt itself of any width (up to 600 mm and more) and the corresponding hardware or reinforced mechanical locks for its reliable fixation.

Type 0/0 Execution and Interaction of the Elevator Belt with the Drive Pulley

In the nomenclature of modern elevator belts, the designation "Type 0/0" is often found. This means that there are no additional rubber covers on the belt surface, and the traction force is transmitted directly by the fabric carcass. For mechanics accustomed to old heavy rubber-cable or thick rubber belts, this solution may seem unusual, but it has a clear engineering justification.

The efficiency of torque transmission depends not on the belt weight, but on the coefficient of friction between it and the pulley. The old school solved the slippage problem by excessive belt tensioning, which "killed" the top shaft bearings and the gearbox. The modern approach to modernizing ZAV complexes offers a different solution:

1. Belt Weight Reduction Using Type 0/0 significantly reduces the own weight of the traction element - this lowers the inertial load during startup and saves electricity.

2. Pulley Lagging Instead of looking for a "sticky" belt, it is more rational to install a lagged (rubber-coated) drive pulley once, which ensures reference grip even with lower belt tension.

The combination of "BKNL Belt (0/0) + Lagged Pulley" is the most rational scheme for modernizing old elevators. It extends the life of bearing assemblies, eliminates slippage and the risk of belt ignition, leaving the equipment in working order for decades to come.

Equipping and Technical Support from Zavod Moroza

The production capabilities of Zavod Moroza allow for solving vertical transport tasks comprehensively, combining time-tested standards with modern engineering solutions. We provide a full cycle of elevator equipping:

• Belts of any configuration - full range of widths and number of plies for equipment of all generations - from basic Soviet-standard models and their modernized versions to high-performance imported lines.
• Modernization and repair elements - efficient polymer and welded buckets, specialized hardware, fasteners, as well as the manufacturing of new lagged pulleys to fit your mounting dimensions.

Our technical department possesses expertise covering the full spectrum of elevator equipment. This allows us to find efficient solutions for every partner - from the operator of a classic ZAV to the technologist of a modern terminal. If you are planning a major overhaul or have doubts regarding load calculations - contact us for a consultation. We will configure the order to ensure maximum resource for your machinery, and for you - confidence in stable equipment operation for years ahead.