Contact Us
Browse by Category
Friend Link
Shaft sealing device technology the new trend of environmental protection
Shaft sealing device technology the new trend of environmentalprotection
At present, in the world, governments and the public's growingawareness of environmental protection to promote the implementationof more comprehensive environmental regulations, which use the pumpall the industrial sector have had enormous impact. In theUnited States, federal clean-air regulations in 1990 amendmentrequires the Environmental Protection Agency (EPA) of the 189 kindsof volatile organic compounds and 454 kinds of volatile hazardousair pollutants in the implementation of more specific restrictionsprecipitates. Refineries and chemical plants by thetransmission pump flow much liquid are considered to be above themain source of precipitates. Pump leakage problem hasattracted attention. Improvement has sealed pump seal deviceis to reduce an important way to pump leakage.
1. Shaft sealing technology Overview
In recent years, World Pumps in sealing technology research anddevelopment achievements very significant, mainly in the newsealing technology, sealing products and sealing systems has threeaspects of progress.
Packing seal as a traditional pump seal structure, because its hasa certain amount of leakage and under the effect of poor inhigh-speed problem, use the area shrinking. However, inrecent years with the phasing out of asbestos rope, in the packingseal technology has also made some new progress. For example,compression packing seal in the entire UK industry is showing itsstrong vitality. This type of synthetic fiber, ceramics andPTFE, such as low-friction material compression filler is betterthan asbestos packing chemical adaptability, wear-resistantability, high temperature and a longer life, but the price is nothigh .
At present, the mechanical seals in pumps sealed to occupy themarket share of growing a variety of newly designed mechanical sealon the market share growth play a significant role. The mostprominent are assembled seal.
This seal is easy to install and maintain, but also safe andreliable, but the price is quite expensive. Anothereye-catching Split mechanical seals are sealed, this seal withoutdismantling pump can be replaced.
There is also hot fluid dynamic pressure seal, spare seals andasymmetrical shape, such as metal bellows seal the newstructure. In addition, the tandem seal and double endmechanical seal structure and a flushing system with the use, toprevent the leakage of dangerous substances and to permittransmission abrasive media.
。 Expected future development of mechanical seals is likely tofocus on the use of "upstream pumping seal-style" and "MagneticFluid Seals" or similar technology to enhance the integrity of theclosed system. "Upstream pumping seal-style" is a use of thesealing surface to sealing surface trough of low pressure side(downstream) of a small amount of leakage of fluid pumped back tohigh-pressure side (upstream) of the new concept. And"Magnetic Fluid Seals" are from the aerospace industry projectsderived new technologies, with no leakage and non-wearcharacteristics.
2. Upstream pumping seal type
"Upstream pumping seal-style" is a use of the sealing surface tosealing surface trough of low pressure side (downstream) of a smallamount of leakage of fluid pumped back to high-pressure side(upstream) of the new concept. It is sealed and double tandemseal between the structure of a hybrid. In the structure andworking principle, the look like a face in two with a low pressurebetween the backup block fluid seal structure. In afunctional context, it played the role of dual seal. Sealedin the main pumping mechanism is as follows: pressure seal blockfrom the low pressure zone to form a weak-side high-pressure mediumpumping capacity. Ordinary type face the main sealed by asmall-capacity high-pressure "pump" - the upper reaches of typepumping seal replaced. This "pump" will block a small amountof liquid along the normally sealed by mechanical seals pathwayforward, and into the sealed cavity. Because of the closedcavity in which fluid pressure above the block, this seal isconsidered to upstream pumping. Upstream pumping seal typecan be applied to toxic and dangerous medium, medium and abrasiveslurry, poor lubrication of various medium and high PV value of theoccasion. Symbols are sealed PV manufacturers and users ofthe expressions used to express in a given combination ofliquid-end material pressure - speed limit. High-speed pumpsusually belong to the high PV value of the use of conditions,because of dual seal required a higher buffer pressure of a dualseal make the situation even worse. Long-term, high-speedpump industry has been troubled by high PV values. Upstreampumping seal type is basically non-contact operation, and thuscompletely eliminate the weight of the PV value. Do not needto because of the high-pressure than the sealed cavity to block thefluid pressure upstream pumping seal type for high-speed pumpsindustrial predicament provides a effective way.