Mechanical seal
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The first question: Regarding the material of the mechanical seal, can the rotating ring be made of graphite while the stationary ring is made of silicon carbide, or could it be made of alloy steel? Or should both rings use the same material? The second question: For double-end face mechanical seals, the contact surfaces between the rotating and stationary rings – some of these surfaces are larger while others are smaller; how is this taken into account in the design? The third issue relates to the compression amount of double-end face mechanical seals
Generally, the moving ring is resin-impregnated graphite, and the friction pair is narrow； ； The static ring is made of silicon carbide or metal alloy, with a wide friction surface ； ； ； However, there are also cases where the static ring is wider than the dynamic ring, but this is very rare! The compression amount of the double-end mechanical seal is predetermined; it can be installed using the positioning features on the shaft sleeve, or it can also be adjusted appropriately!
The first question is that most options use different materials, such as silicon carbide combined with graphite. The second question is: are the static rings generally narrow? It has to do with the material; how to combine them? I don’t understand this question. For the third question, modern modular mechanical seals don’t require confirmation of the compression amount; there are positioning blocks provided, and one just needs to install them according to those positioning blocks.
Generally, two different materials are paired together, with the relatively softer material having a narrower surface and the harder material having a wider surface. There are also pairs made of the same material. The width of the contact surface can be calculated and adjusted based on the spring force and the medium pressure. The modular seal features quick positioning; the spring is already adjusted, and it just needs to be installed as required. The last two images do not represent true container sealing; it is necessary to calculate the axial dimensions carefully, although the sealing manufacturer shown in the images has already done this calculation.
This refers to the sealing of multi-stage pumps. The wide and narrow faces are determined based on the area-to-pressure ratio; seals can be classified as balanced or unbalanced types. Generally, in high-pressure applications the static ring has a larger area, and such seals belong to the unbalanced type, while those with a smaller static ring area are used in low-pressure applications and belong to the balanced type. The compression amount for double-face pack sealings is currently designed by the manufacturers, and the measurement calculations are simple. The principle of measurement is the same as that for single-face seals; it mainly involves determining the distance from the static ring to the sealing surface of the seal gland, with the other measurement methods being identical to those used for single-face seals.
I would like to ask what exactly you mean by high pressure and low pressure