ESD34N

Function
The shaft seal type ESD34N is a double-acting bidirectional mechanical seal made to DIN standards. It can be applied to vessels made to DIN 28136 of steel or stainless steel with mounting flanges according to DIN 28141 fitting shaft ends made according to DIN 28154. The shaft seal type ESD34N is designed with a total of four seal rings, with two identical seal ring pairs arranged back-to-back. Product and atmospheric side seal ring pairs are hydraulically balanced via flexible secondary seals. This ensures that the position of the seal rings remains unchanged also if the pressure acting on the seal is reversed. Since the flexible secondary seals are only mechanically loaded by the force of the springs acting on the seal rings, their elasticity is retained. This principle allows high radial deflection of the shaft without any negative influence on the sealing gap and consequently on the sealing effect.

Applications
The shaft seal type ESD34N is the ideal mechanical seal for applications in the low pressure range up to 7 bar (abs.). Due to its modular design it can be modified to suit various needs. By having product wetted parts that are small in size, materials such as Titanium, Hastelloy or even glass-lined parts can be used economically. Because of its compact size this seal type is also highly suitable for installation in small spaces making it the ideal replacement for stuffing box seals.

The seal type ESD34N can be operated with a seal supply system that is under atmospheric pressure or under a constant pressure overlay. In the first case the atmospheric side seal ring pair does not carry any load and therefore serves as an emergency seal. Leakage of the seal liquid to the atmospheric side is thus avoided. In the second case the product side seal ring pair is only loaded with the pressure difference between the pressure overlay and the vessel pressure. In contrast to this the atmospheric side seal ring pair has to bear the higher pressure difference, namely that between pressure overlay and atmospheric pressure.

The main areas of application are:
        Chemical industry
        Hydrometallurgy
        Pharmacy
        Biotechnology
 
Quality
The shaft seal type ESD34N is supplied ready for installation as a cartridge unit. Prior to delivery every mechanical seal is dynamically tested under process conditions according to an internal QM System that conforms to DIN EN ISO 9001:2000, and receives a test certificate. The seal type ESD34N can be supplied to suit GMP requirements and is TÜV certified for applications in hazardous areas in accordance with ATEX standard 94/9/EC.

Application Limits
Vessel pressure: Vacuum ... 7 bar (abs.)
Vessle temperature: -50 … +400° C
Shaft size: 40 ... 120 mm
Sliding speed: 5 m/s

Materials
Housing: Stainless steel
Product-wetted parts: Stainless steel, Hastelloy, Titanium, other special materials
Seal rings: Carbon, Silicon Carbide, Tungsten Carbide, etc.
O-rings: Viton, EPDM, Perfluor elastomers, special materials
FDA-approval: Possible for all product-wetted parts