ESD74/ESD84

Principle
The lift-off, gas-lubricated ESD74 and ESD84 mechanical seals are double-acting, unidirectional seals conforming to DIN standards. They can be fitted to carbon steel or stainless steel vessels with DIN 28141 mounting flanges and plain shafts (DIN 28154).

The two seal rings are forced apart by a cushion of gas, the gas pressure being adjusted to minimize the flow of gas through the gap between the seal faces into the product space and to atmosphere. A special groove geometry in the seal faces causes the seal rings to be forced apart even at low shaft speeds. As there is no contact between the seal rings, there is no wear of abrasion, thus avoiding contamination of the product in the vessel.

Integrating the bearing in the mechanical seal assembly ensures that the two seal ring pairs are ideally positioned, even when large radial forces are exerted and the shaft is deflected.

All parts of the mechanical seal assembly are manufactured in standard grades of stainless steel. For special applications, however, productcontacted components can be supplied in more corrosionresistant materials such as Hastelloy, with O-rings in any commercially available polymer.

ESD74
The ESD74 mechanical seal is used when it is essential to avoid contamination of the vessel contents by a seal liquid or the products of wear, or if a very long service life is required for the mechanical seal. This seal is very compact and is easy to disassemble.

ESD84
This mechanical seal also complies with all requirements resulting from sterile operation (GMP). It can be thoroughly cleaned without any great effort. All potential bug traps have been rigorously eliminated.

As the lower seal ring pair projects into the product space, it is possible to clean its external contours with the existing cleaning system. A second hole drilled in the seal housing also makes the internal chamber accessible to conventional cleaning processes (CIP/SIP). Product-contacted components are available with FDA approval and special surface finishes.

Applications
As with all ESD mechanical seals, the focus is on meeting process requirements. The ESD74 and ESD84 seals combine high precision engineering and manufacturing technology with the ruggedness to withstand the harsh conditions encountered in process equipment. Robustness was a key consideration in the design of this series of mechanical seals. Finite element analysis was used in their development, ensuring a high degree of reliability even under extreme conditions. The solid seal rings, for example, have emergency running properties, so even if they make contact they will not be damaged.

ESD74 and ESD84 mechanical seals are very easy to service, all maintenance work being uncomplicated. It is not necessary for EKATO ESD to readjust the seal ring pairs afterwards.

The main fields of application include:

• Pharmaceuticals
• Food processing
• Cosmetics
• Chemicals
• Biotechnology

Gas supply system ESD GVS
The ESD GVS gas supply system ensures optimum operating characteristics and in consequence a high degree of reliability for the ESD74 and ESD84 lift-off mechanical seals. The seal gas is monitored and controlled to meet the requirements of the process and the mechanical seal. Individual components can be monitored electrically, depending on the application concerned and customer needs.

The ESD GVS gas supply system is supplied as a completely assembled and tested compact unit. This means that expensive installation work is not required and the mechanical seal system can be fitted quickly.

In general all inert gases or mixtures of gases can be used as seal gas.

The ESD74 and ESD84 mechanical seals and the ESD GVS gas supply system have been inspected for explosion protection duties, i.e. they comply with the requirements of the ATEX Directive 94/9/EC.

Quality
ESD74 and ESD84 mechanical seals are supplied as ready-to-install cartridge units. Under the internal QM system certified to DIN EN ISO 9001:2000, each mechanical seal is tested dynamically under process conditions and is assigned a test certificate before it leaves the factory.

Application Limits
Vessel pressure: Vacuum ... 7 bar (abs.)
Vessel temperature: 0 … +135° C
Shaft size: 40 ...120 mm
Sliding speed: 10 m/s
Sealing pressure: max. vessel pressure +2.5 bar

Materials
Housing: Stainless steel
Product-wetted parts: Stainless steel, special materials
Seal rings: Carbon, Silicon carbide
O-rings: Viton, EPDM, Perfluor elastomers, special materials
FDA approval: available for all product-wetted parts