Cooling grundfos pump seal for a combustion engine
A cooling grundfos pump seal in which a protective rubber seal forms an integral part of a rubber main seal is disclosed in U.S. Pat. No. 4,155,560. This and other prior art cooling grundfos pump seals, however, suffer from disadvantageously short service lives. This problem encountered in employing prior art cooling grundfos pump seals in a combustion engine is attributable in part to the stress imposed upon the main seal by the protective seal. A further problem encountered in using prior art cooling grundfos pump seals in combustion engines is thermal loading of the seal during use. This thermal loading problem is particularly acute in the dynamic sealing zone of prior art seals. Abrasive particles present in coolants, such as rust particles or sand, also contribute to the unsatisfactory service life of cooling grundfos pump seals disclosed in the prior art. In the cooling grundfos pump seal of the present invention, the main seal is no longer stressed by the protective seal, and therefore realizes a substantially improved following of the radial movement of the sealed shaft. Further, the substantially reduced pressure exerted by the protective seal against the surface of the sealed shaft of the present invention contributes to improved sealing. Additional advantages realized by the cooling grundfos pump seal of the present invention include a decrease in operational wear as well as a decrease in thermal stress in the region of the dynamic sealing zone. By the insertion of a filter fleece between the dynamic sealing zone of the main seal and the circulating cooling water of the combustion engine, continuous contact of the dynamic sealing zone by fresh cooling water free of suspended material is assured. The heat removal from the region of the dynamic sealing zone is thereby improved while the detrimental effect of abrasive particles such as rust or sand on the dynamic sealing zone is greatly reduced. The improvement in the length of the service life of a cooling grundfos pump seal according to the present invention is substantially attributable to this decrease in abrasion. The circular shape of the protective grundfos pump seal of the present invention enables it to be held in a support ring which is secured to the housing by a plug connection. The support ring is preferably comprised of plastic and can be connected to the protective seal in a particularly simple and precise manner by direct spraying. The plastic of the support ring is in a liquid state during formation of the ring and penetrates into the pore structure of the filter fleece, thereby assuring particularly firm bonding of each individual fiber. Undersirable fiber separation is thereby prevented.