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The standard specifications for double mechanical seal parts primarily involve structural design, performance parameters, material selection, and installation maintenance. They must comply with industry-wide standards (such as DIN 24960) and specific operational requirements.
1. Core Standards and Specifications
Double mechanical seals must comply with multiple industry standards, with DIN 24960 being the most commonly used general standard, applicable to unbalanced, bidirectional double mechanical seal parts for scenarios involving flammable, explosive gases, and highly corrosive media. Additionally, some products are marked as compliant with EN 12756, emphasizing compact design and installation compatibility.
2. Key Technical Parameter Requirements
The following are the typical technical parameter ranges for double mechanical seal parts:
Parameter Category Standard Range Special Operating Conditions Requirements
Temperature: -50°C to +220°C, up to 320°C
Pressure ≤2.5MPa, high-pressure type up to 4.0MPa
Shaft diameter: 12mm to 250mm, custom options available for larger sizes
Linear velocity ≤10m/s4, high-speed type can reach 15m/s
3. Structural and Material Specifications
Structural Design
It must include two sets of sealing faces (dual dynamic rings + dual static rings), support layouts such as "back-to-back" and "face-to-face," and ensure secondary sealing continues when the primary seal fails.
An external sealing fluid system must be installed to achieve lubrication and cooling through a buffer tank or isolation tank, with the pressure typically 0.01–0.03 MPa higher than the medium pressure.
Material Selection
The moving ring is typically made of tungsten carbide or alloy, while the stationary ring is constructed from resin-impregnated graphite or metal-ceramic to ensure wear resistance and corrosion resistance.
Springs and auxiliary seals must withstand medium temperature and chemical corrosion. For general working conditions, stainless steel springs are suitable, while Hastelloy alloy is required for high-temperature environments.
4. Installation and Maintenance Standards
Installation accuracy: The end face tilt error of the gland shall be ≤0.05mm, the spring compression error shall be ±2mm, and the moving ring must be able to rebound freely.
Rinse system: Equipped with a pressure switch and a level gauge to monitor the status of the sealing liquid, with buffer liquid circulation achieved through an internal pump loop.
5. Application Scenarios and Compliance
Double-end mechanical seals are primarily used for handling toxic, flammable, high-viscosity, or particulate media, such as in desulfurization slurry pumps, reactors, and similar equipment. They must pass a hydraulic test (with test pressure being 1.5 times the operating pressure) and leakage detection (≤5 drops per minute).
