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| ANSI AMERICAN NATIONAL STANDARD INSTITUTE ASME AMERICAN SOCIETY OF MECHANICAL ENGINEERS 1962 The first attempt was made in America to standardize pumps in the chemical industry. The results of these efforts were put together in the American Voluntary Standards (AVS). 1968 A revised version was approved by ANSI. 1991 Revision ASME B73.1 M - 1991 was published, which is discussed below. ASME B73.1 M - 1991 HORIZONTAL END SUCTION CENTRIFUGAL PUMPS FOR CHEMICAL PROCESS Of course the standard also addresses seal parameters. Particularly helpful: ASME B73.1 M - 1991 makes a clear distinction between packing installation and mechanical seal installation. Stuffing boxes have conventional dimensions (see Fig. 1). The mechanical seal chambers are larger, and the standard recommends tapered chambers in some instances (see Fig. 2 + 3). These revisions of industry standards and recommendations are very welcome, because manufacturers can significantly improve the service life of their mechanical seals. Please note: Not every pump manufacturer adheres to these standards. Not every detail listed in the standard (e.g. balanced/unbalanced) reflects the current state of technology. Conversion from packing to mechanical seals There are still a lot of pumps around which were not manufactured in accordance with the latest recommendations. There are also a lot of pumps out there with packing as the sealing element which the users would like to replace with mechanical seals. It is important to keep in mind that a mechanical seal which was designed for a seal chamber with a 3/4" (19.05 mm) cross section is certainly not compatible with a 5/16" (7.94 mm) stuffing box and vice versa. It is important that you check the equipment configuration before you select a mechanical seal. Environment checks, PLAN numbers The ANSI / ASME standard contains a series of seal plans, which can help create a favorable environment for mechanical seals. Implementation of these plans can often increase mechanical seal service life. It may be necessary to combine elements from several of the plans in certain mechanical seal applications (see the following pages for details). Application The industry is looking for longer service life to avoid expensive maintenance and downtime, but it is often unwilling to select the mechanical seals and plans which will actually extend service life. A change in attitude would be welcome. DEPAC offers more! DEPAC mechanical seals are designed to a high technological standard, and stationary design is one of the outstanding features. The seals exceed the requirements which are defined in the standards. A number of the technical details which go beyond the standards significantly increase the reliability and efficiency of mechanical seals during ongoing operation. |
STUFFING BOX for Installing Packings Fig. 1: 
STUFFING BOX for Installing Packings Fig. 2: Cylindrical Chamber  Fig. 3: Conical Chamber 
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