Teflon Bellow Mechanical Seal

A: PTFE properties include outstanding low and high-temperature capability as well as resistance to weathering. Examples of PTFE seal applications include oilfield equipment, compressors, mechanical seals, hydraulic actuators, aircraft engines, brake systems, food processing equipment, and more.

A: The primary function of bellows seal valves is preventing potentially harmful or toxic fugitive emissions which can negatively affect unprotected humans and the surrounding environment.

A: PTFE bellows are commonly used in chemical processing equipment such as pumps, valves, and reactors. Their resistance to aggressive chemicals and high temperatures makes them invaluable in this industry.

A: PTFE offers many distinct advantages over elastomers. These advantages include corrosion resistance, massive temperature range capabilities, excellent electrical properties and an almost unlimited shelf life, to name a few.

A: Teflon and other functional coatings from an experienced applicator can solve design problems including excessive wear, sticking, noise, and corrosion. Teflon, or polytetrafluoroethylene (PTFE), is one of the most versatile industrial coatings available.

A: These PTFE seals must be installed dry, without the use of grease or lubricants, to ensure optimal performance. Firstly, let's explore the structure and operational principles of Teflon seals (or PTFE seals).

A: The layer of PTFE will eventually start to wear off with a life expectancy of five to seven years, an improvement from its previous two to three years life span.

A: Many industrial Teflon coatings can withstand temperatures as low as -250ºF without loss of physical properties and can operate continuously at temperatures up to 260°C/500°F.

A: Bellows seal valves incorporate a cylindrical metal tube that expands and contracts like an accordion to create a hermetically sealed closure in a valve stem. The bellows get compressed when the valve is in the open position and expands when the valve is closed.

A: The seal faces are pushed together using a combination of hydraulic force from the sealed fluid and spring force from the seal design. In this way, a seal is formed to prevent process leaking between the rotating (shaft) and stationary areas of the pump.

A: Bellows Mechanical Seals are also known as non-pusher seals as they have a static secondary seal which stays in place against the shaft, sleeve or on the gland of the pump.

A: This prevents the liquid from leaking through the clearance between the pump body and the shaft. Mechanical seals are mostly comprised of two rings: a rotary ring on the shaft and a stationary ring on the pump housing. The rotary ring rotates with the shaft.

A: In mechanical seals, in addition to the closing force generated by the springs or bellow, an hydrostatic force generated by the fluid pressure acts on the seal ring. As previously discussed the fluid pressure also penetrates between the seal faces, producing a lubrication film and generating an opening force.

A: The operation of a mechanical shaft seal is based on the application of pressure, creating a sealing surface between the rotating and stationary parts. This pressure is achieved through a combination of springs, pressure plates, or pressure levels, maintaining a tight contact to prevent fluid or gas leakage.

A: Several problems can lead to mechanical seal failure, including dry running, improper installation, and chemical degradation. By understanding these factors, you can implement adequate preventive measures to reduce seal component failures and prevent mechanical seal leakage.

A: On the back side of the "seal head" (the end which fits towards the "spring"), measure the inside diameter. This will determine the seal size diameter - which is either the shaft size or the sleeve size that the seal fits over. The front side of the seal usually has a black carbon face.

A: To accurately measure your mechanical seal, you must separate each component and calculate its dimensions individually: Remove the seal face from the spring and assess its inside diameter. This will determine the shaft or the sleeve size. Next, determine the length of the spring once separated from the seal face.

A: Sealing at the primary faces is accomplished by having the two faces that are lapped and held together with enough force to form a seal. Held together by axial force from the closing mechanism (spring or bellows) and byproduct pressure in the seal chamber.

A: As a means of quantifying the amount, or percent, of balance for a mechanical seal, a ratio can be made between the seal face area above the balance diameter versus the total seal face area. This ratio can also be expressed as the area of the seal face exposed to hydraulic closing force versus the total seal face area.

A: Mechanical seals are typically used for pressures up to 1000 psi. They have the added feature of providing more positive sealing during shutdown. They rely on the continuous contact between a rotating and fixed seat that are separated by a carbon ring.