The selection of sealing components must consider the working conditions, in order to choose the appropriate form and material of the sealing components, as well as the installation structure. The working conditions that need to be considered generally include: temperature, pressure, and medium. Other factors need to be considered for selection based on the characteristics of the equipment itself.

Regarding temperature, for example, the working temperature range of NBR materials is generally -40 to 120 ℃. If it exceeds 120 ℃, FKM or even PTFE materials should be considered. Low temperature situations are relatively rare. Generally speaking, cold resistant NBR should be considered for use in temperatures ranging from -20 to -40 ℃. Ordinary NBR materials can harden in low temperature environments, leading to leakage. For example, railway locomotives often encounter such problems in winter in the north.

As for pressure, it affects the form of the seal to be selected. Generally speaking, the use of rubber or PU seals for low and medium pressure will not cause significant problems. However, there is a need to consider the issue of impact pressure. For example, in construction machinery, the impact pressure during startup and shutdown is much greater than the normal working pressure. Therefore, HBY or SPGW with a pressure resistance of up to 70MPA and anti extrusion clearance are often selected as the main seals. PTFE combination seal is also a commonly used option.

The issue of media is relatively simple. Just need to pay attention to some special small issues, such as the use of water ethylene glycol and phosphate ester hydraulic oil in oil cylinders in the metallurgical industry. Sometimes, although the working temperature is not high, one still needs to be very careful when choosing materials. When using the latter hydraulic oil, FKM should still be chosen.

The selection of sealing components is very important, and it must be based on the equipment itself. For example, if you need to be responsive and precise in control, of course, you can choose the Steffengelle ring. High reliability is required, and Hongger's GD1000K series or NOK's SPGW are often chosen. For example, when engineering machinery is working in the field, there are often impacts and low temperature weather, and its dust ring will be made of exposed metal frame to prevent it from falling off.

The seals of cylinders, compressor piston rings, high-pressure oil seals, and oil pumps in various scientific instruments all require special structures to meet the requirements.

All of these are different, welcome to discuss with me the selection of sealing components

What is common knowledge about mechanical seals?

Mechanical seals are one of the precision and structurally complex mechanical basic components, and are key components of various pumps, reaction synthesis kettles, turbo compressors, submersible motors, and other equipment. Its sealing performance and service life depend on many factors, such as selection, machine accuracy, correct installation and use, etc.

1、 Selection method

According to different working conditions and medium properties, mechanical seals include high-temperature and low-temperature resistant mechanical seals, high-pressure and corrosion-resistant mechanical seals, particle resistant mechanical seals, and mechanical seals suitable for light hydrocarbon media that are prone to vaporization. Different structural types and materials of mechanical seals should be selected according to their different uses.

The main parameters for selection include: sealing chamber pressure (MPA), fluid temperature (℃), working speed (M/S), fluid characteristics, and effective space for installing seals.

What is the common knowledge of mechanical seals, and the basic principles for selection are:

1. According to the pressure of the sealed chamber, determine whether the sealing structure adopts balanced or unbalanced type, single end face or double end face, etc.

2. According to the working speed, determine whether to use rotary or static, fluid dynamic pressure or non-contact type.

3. Determine the friction pair and auxiliary sealing materials based on temperature and fluid properties, as well as correctly select mechanical seal circulation protection systems such as lubrication, flushing, insulation, and cooling.