Double Cartridge Mechanical Seal Parts Combination

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Background Knowledge:

                                                                                   Overall Installation of mechanical seals（2）
                                                                                                       【I】order of installation
1.Determine the installation position of the mechanical seal
(1) Determine the installation position of the rotating parts on the shaft according to the mechanical seal assembly drawing (according to API-610, the contract materials include the operation and maintenance manual of the pump and the mechanical seal, and the separate drawing of the mechanical seal).
(2)Draw a line on the shaft to mark the position of L, if you are disassembling the machine, mark the original installation position on the shaft with a line. Then it will be easier to install the mechanical seal again.

2. Install stationary parts
(1) First install the anti-rotation pin1 in the pin hole of the sealing cover of the mechanical seal. Regardless of whether the vertical or horizontal anti-rotation pin is press-fitted, pay attention to the depth of the inserting, so that the prolonged pin should not touching the bottom of the groove of the stationary seat （holder）or the shaft surface.
Looking at the former picture.
(2) Put the stationary seal ring2 on the stationary seat3, and align the groove of the stationary seat with the anti-rotation pin1 in the cover10 , and push it evenly into the cover 10 of the mechanical seal.

3. Assemble the rotating parts
(1) Place the spring adapter 4 of the mechanical seal up and flat, and then put the multiple springs 5 into the holes of the spring adapter, not skewed.
(2)Put the rotary face’s sealing ring 6 into the rotary face 7, and then put the pressure ring 8 on the rotary face of the mechanical seal . Note that the pressure ring should press the sealing ring 6.
（3）Put the pressure ring, the sealing Ring of the rotary face and the rotary face into the spring holder 4 of the mechanical seal together. Note that the groove on the outer diameter of the rotary face should be aligned with the protruding part of the spring holder.
（4）Put the spring holder together with the spring, pressure ring, rotary face and its seaingl ring on the marking position on the shaft of the mechanical seal, and then fix the rotating part on the shaft with the fixing screw 9.
Regarding the top compression amount of the spring, foreign drawings set it to be 4mm, and domestically it is generally 4~6mm, depending on the size of single spring, multiple springs and springs of the mechanical seals.
After the rotary face is installed, it must be able to move flexibly on the shaft of the mechanical seal. After the rotary face is pressed against the spring, it can automatically spring back.
（5）Install the assembled cover 10 on the stuffing box body, and tighten the bolts evenly in several times (using the PTFE O-ring, tightening work of each bolt must be at least 30 minutes apart, and be repeatedly done until there is no need to continue it).
（6）After the final assembling of the mechanical seal, check whether the auxiliary equipment is normal, check whether the cooling, circulation, ventilation, discharge, blocking and other pipeline joints are connected correctly. It is required that the inlet of the steam drop pipeline is at the upper part and the outlet the lower part; the cooling pipe inlet is at the lower part and the outlet at the upper part. After checking by craning, it should be light and flexible without jamming. Under normal circumstances, the radial runout of the shaft should be checked after the final assembling, and then it should be delivered to use after the static pressure test and a period of running-in.

The disassembling sequence of the mechanical seal is opposite to the installation sequence. It is strictly forbidden to use iron wares
to knock it out during disassembling of the mechanical seal. It is best to use a special tool to disassemble in order. If there is dirt on the sealing element or the coagulant is dried up, the dirt should be cleaned before disassembly.

                                                                      【II】Starting operation of the Mechanical Seals and its Preparations
1.Comprehensively check whether mechanical seals and auxiliary devices, pipelines, valves, instruments, etc. are fully installed. The pipelines must be cleaned to prevent clogging. This is particularly important for new devices. Because impurities often enter the seal from the pipeline to affect the sealing performance. The whole system should be evacuated to prevent the formation of air locks at the height of the seal chamber, which may cause dry friction operation.
2.Perform a static pressure test before starting. The test pressure is the same as the working pressure; check the mechanical seal itself and related sealing points and joints for leaks. If there is any leakage, try to deal with it.
3.wheel the pump and motor at the point of coupling artificially in the direction of the rotation of the pump. The whole mechanical seal equipment can only be delivered to use after it meets the requirements.

These are the preparations. Below comes the formal operation procedures：
1.Before the main engine of the mechanical seal is started, the seal chamber should be kept full of liquid or sealing medium. If there is a separate auxiliary sealing system, it should be started first.It is the same when speaking of the cooling water system,which should be stopped at last among the whole equipment; When conveying solidified medium or media of very large viscosity , use steam to heat the seal chamber to melt the media. The vehicle must be cranked before starting to prevent sudden start leading to the soft ring’s rupture.
2.Operate the mechanical seal under normal pressure before formal use and observe whether the temperature rise of the sealing part is normal. If there is a slight leakage, you can run in for a period of time, like 1~3 hours, to make the end surfaces fit more evenly until the leakage is gradually reduced to normal amount. If the hourly leakage does not decrease, you need to stop for inspection.
3.Boosting and heating operation: the mechanical seal that has passed the test of normal pressure operation should be operated in time under increased pressure or temperature with the same operating conditions.The pressure increase and the temperature increase tests can be carried out separately. The process of the increase should be slow, and attention must be paid to the pressure increase (or temperature increase) ) accidents that may occur during the process, such as the machine parts’ collide, the end faces‘ being disengaged, the too fast friction heating, and the anti-rotation pin’s being disengaged or damaged, and etc. One should check whether the pressure is stable (pressure fluctuation is no more than ±0.1MPa) and Whether there is leakage at the sealing ring and the sealing end face as well. if everything is normal, the mechanical seal can be put into production.