|
An end face mechanical seal, also referred to as a mechanical face seal but usually simply as a mechanical seal, is a type of seal utilised in rotating equipment, such as pumps, mixers, blowers, and compressors. When a pump operates, the liquid could leak out of the pump between the rotating shaft and the stationary pump casing. Since the shaft rotates, preventing this leakage can be difficult. Earlier pump models used mechanical packing (otherwise known as Gland Packing) to seal the shaft. Since World War II, mechanical seals have replaced packing in many applications. An end face mechanical seal uses both rigid and flexible elements that maintain contact at a sealing interface and slide on each other, allowing a rotating element to pass through a sealed case. The elements are both hydraulically and mechanically loaded with a spring or other device to maintain contact. For similar designs using flexible elements, see Radial shaft seal (a.k.a. "lip seal") and o-rings. ==Mechanical seal fundamentals.== A mechanical seal〔http://www.mechanicalseals.net/〕 must contain four functional components, primary sealing surfaces, secondary sealing surfaces, a means of actuation, and a means of drive: # The primary sealing surfaces are the heart of the device. A common combination consists of a hard material, such as silicon carbide, Ceramic or tungsten carbide, embedded in the pump casing and a softer material, such as carbon in the rotating seal assembly. Many other materials can be used depending on the liquid's chemical properties, pressure, and temperature. These two rings are in intimate contact, one ring rotates with the shaft, the other ring is stationary. These two rings are machined using a machining process called lapping in order to obtain the necessary degree of flatness. # The secondary sealing surfaces (there may be a number of them) are those other points in the seal that require a fluid barrier but are not rotating relative to one another. Usually the secondary sealing elements are o-rings, PTFE wedges or rubber diaphragms. # In order to keep the two primary sealing surfaces in intimate contact, an actuation force is required and is commonly provided by a spring. In conjunction with the spring, it may also be provided by the pressure of the sealed fluid. # The primary sealing surfaces must be the only parts of the seal that are permitted to rotate relative to one another, they must not rotate relative to the parts of the seal that hold them in place. To maintain this non-rotation a method of drive must be provided. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「End face mechanical seal」の詳細全文を読む スポンサード リンク
|