The DYW200-224 Series is a complete, integrated, spring-applied, hydraulically released drum brake system designed specifically for hazardous environments. Unlike standalone thrusters, this series is a fully engineered brake package that combines an explosion-protected (Ex) hydraulic power unit with a matched, heavy-duty drum brake caliper to provide safe, reliable, and powerful braking for machinery in potentially explosive atmospheres.
Core Concept & Design Philosophy
This is not just a component; it is a complete braking system solution designed to meet the stringent safety requirements for Zone 1, 2, 21, and 22 areas. The design philosophy is modular, separating the power generation unit (which requires explosion-proofing) from the mechanical brake caliper. This allows for flexible mounting and easier maintenance.
Key Components:
Explosion-Protected Hydraulic Power Unit (HPU): The "DYW" prefix denotes a compact, certified power pack. It contains an Ex-rated motor, pump, reservoir, and valve block, all housed in a flameproof enclosure. It is the "brains and muscle" of the system.
Drum Brake Caliper: The "200-224" indicates a large, powerful brake caliper (often with a 224mm or similar diameter brake drum specification) that acts directly on the drum's external surface. It includes the brake shoes/pads, actuation lever, and a powerful internal spring for fail-safe operation.
Working Principle (Fail-Safe by Design)
Release: When energized, the Ex HPU pressurizes hydraulic fluid. This pressure is transmitted via a high-pressure hose to a hydraulic cylinder (often integrated into the brake caliper). The cylinder piston extends, compressing the powerful internal spring(s) and retracting the brake shoes, thereby releasing the brake.
Application: Upon power loss, shutdown, or a manual emergency signal, the HPU depressurizes. The stored energy in the compressed brake springs forces the piston back, pushing hydraulic fluid back to the reservoir, and forcefully applies the brake. This is the critical spring-applied, hydraulically released (SAHR) principle.
Key Features & Specifications
Certified Explosion Protection: The entire electrical and power generation assembly (HPU) is certified to ATEX/IECEx standards, typically as Ex d IIC T4 Gb for gases and Ex tD A21 IP6X T135°C Db for dust. The brake caliper is usually certified as a "non-electrical" device or as part of the assembly.
High Braking Torque: The "200-224" designation signifies a large brake size capable of generating very high static braking torque, suitable for heavy loads, high inertia, or large diameter drums (e.g., 200mm brake pad width for a 224mm drum).
Spring-Applied, Hydraulically Released (SAHR): This is the defining safety feature. Braking is automatic and positive upon any failure (power loss, hydraulic leak, hose rupture).
Modular & Flexible Design: The HPU can be mounted remotely (e.g., on a stationary structure), connected to the brake caliper (mounted on the moving machinery) via flexible hydraulic hoses. This simplifies installation and service.
Manual Release Mechanism: The HPU incorporates a manual release screw/valve. This allows an operator to mechanically release hydraulic pressure and thus the brake for maintenance, repositioning, or in case of HPU failure.
Adjustable Braking Force: The caliper typically features an adjustment mechanism to compensate for brake lining wear and to set the initial air gap.
Typical Technical Data
Brake Drum Diameter: 224 mm (standard for this series).
Braking Torque: Ranging from several hundred to over a thousand Newton-meters (Nm), depending on the specific model and spring configuration.
HPU Motor: Ex d certified, typically 0.37 kW to 0.75 kW, 380V/415V 3-phase, 50Hz.
HPU Rated Pressure: ~ 50-70 bar.
Release Time: Adjustable via throttle valves (typically 0.5 - 3 seconds).
Protection Class: IP65/IP66 for the HPU and caliper.
Primary Applications
This system is engineered for heavy-duty, safety-critical braking in hazardous locations on:
Mine Hoists (Winders) and Incline Haulages.
Overhead Cranes in Chemical Plants, Offshore Platforms, and Refineries.
Shipboard Cranes and Davits.
Large Conveyor Drives in grain, coal, or mineral processing plants (dust explosion hazards).
Process Machinery with large rotating drums or winches in Ex zones.
Advantages
Complete Certified System: Simplifies compliance-the entire brake system is supplied and certified as a matched package.
Maximum Safety: SAHR design ensures automatic, positive braking in any failure scenario.
High Power in Compact Form: Hydraulic power delivers very high forces in a compact HPU, allowing for a powerful brake caliper.
Remote & Robust: The brake caliper can be installed in harsh, exposed locations (heat, dust, moisture), while the HPU is mounted in a more accessible, protected spot.
Summary
The DYW200-224 Series Explosion-Protected Electro-Hydraulic Drum Brake is a premium, integrated braking system for the most demanding applications in hazardous areas. It combines the safety of certified explosion-proof components, the reliability of hydraulic power, and the fail-safe action of spring-applied brakes into a single, high-torque package. It is the solution of choice where personnel safety, environmental protection, and equipment security in explosive atmospheres depend on absolutely certain braking action.
