Single end large spring mechanical seal

Single end large spring mechanical seal

Sanitary pump mechanical seal

basic characteristics

•structure:Single end face

•pressure:Low pressure mechanical seal

• Speed:Conventional speed mechanical seal

• Temperature:Temperature of mechanical seal

• Performance:corrosion-resistant

• Standards:Specific customization

The model is not available

•balance:notbalance

•Specifications:inner diameter:6-38mm

Single end large spring mechanical seal product detailed description

It is a common type with good stability and reliability, widely used in clean water pumps, sewage pumps, submersible pumps, chemical pumps, and so on.

structural characteristics: Single end seal, unbalanced type, conical spring, depending on the direction of rotation.

industry standard: Specific customization.

Scope of Application: Widely used in clean water pumps, sewage pumps, submersible pumps, chemical pumps, and so on.

operating parameters:

•pressure:1 MPaor below

•temperature:-20 ~ 180ºC

•linear velocity:10rice/second

material:

• Rotating torus:SiC/TC

• Fixed torus:carbon/silicon carbide/TC

• Elastic body:NBR / EPDM /fluororubber/ Clear

•spring material:SS304 SS316 / hac - 276

• Metal parts:SS304 / SS316 / SS316L

medium:Oil, water, solvents, and pulp.

Personalized customization: can adapt to actual working conditions by changing the material. Please contact us if needed.

Installation of mechanical seals

1、 Preparation work before installation

（1）Check whether the model and specifications of the installed mechanical seal are correct, whether the parts are intact, whether the sealing ring size is appropriate, and whether the dynamic and static ring surfaces are smooth and flat. If there are defects, they must be replaced or repaired.

（2）Check whether the fitting dimensions, roughness, and parallelism of each component of the mechanical seal meet the requirements.

（3）When using a small spring mechanical seal, it is necessary to check whether the length and stiffness of the small spring are the same. When using a coil or hook spring transmission, attention should be paid to whether its rotation direction is consistent with the rotation direction of the shaft. The discrimination method is to use a right-handed spring for those facing the end face of the moving ring and rotating clockwise with the axis of rotation; For counterclockwise rotation, use a left-hand spring

（4）Check if the accuracy of the equipment meets the requirements for installing mechanical seals.

（5）Clean and seal related parts such as shaft surface, sealing chamber, sealing chamber end cover, etc. And ensure that the sealing liquid pipeline is unobstructed.

（6）During the installation process, cleanliness should be maintained, especially the sealing end faces of the dynamic and static rings and the surface of the auxiliary sealing ring should be free of impurities and dust. It is not allowed to wipe the sealing end face with unclean cloth. To prevent dry friction during startup, a small amount of clean engine oil can be applied to the sealing end faces of the dynamic and static rings. During installation, it is not allowed to use tools to strike the sealing components to prevent damage to the seals.

（7）When the sealing ring is in place, twisting should be avoidedODo not use auxiliary sealing ringsORoll the circular ring onto the stationary ring seat and gently insert itOEnlarge the circle (see figure)11-11）. During the installation process, when passing through holes, steps, and keyways, be careful to avoid all possible scratches. If necessary, polytetrafluoroethylene can be usedOPlace the circular ring in boiling water first to allow it to expand slightly before installation. Lubricants can be applied to the shaft or sleeve, but attention must be paid to whether the lubricant is compatible with the elastic material. Namely: Mineral oil cannot be mixed withEPRubber (ethylene propylene diene monomer rubber) is used in combination. Silicone oil is available for most materials, but cannot be used for silicone rubber. If it is inconvenient to use lubricating oil, water or soft soap can be used.

2、 Installation sequence

After the installation preparation is completed, the installation can be carried out in a certain order according to the user manual and the general assembly drawing, completing the installation of stationary components inside the end cover and rotating components on the shaft, and finally completing the overall assembly installation of the seal.

After installation, it should be turned and observed for any contact. If the turning feels heavy, it is necessary to check whether the shaft touches the stationary ring and whether the seal touches the sealing chamber. Otherwise, measures should be taken to eliminate it. Conduct static and dynamic pressure tests, and only after passing the tests can it be put into formal use.

3、 Installation precautions

（1）The installation precautions for mechanical seals of centrifugal pumps with different structures. Centrifugal pumps are widely used in the process industry, and different structures of centrifugal pumps have different mechanical seals during installation. The following issues need to be noted.

The characteristic of a cantilever centrifugal pump is that the shaft is already installed in the bearing box, while the pump body and impeller are not installed. Before installation, the compression capacity and the position of the transmission seat should be determined and marked on the shaft sleeve. When installing, first fit the end cap with the static ring onto the shaft sleeve, then install the shaft sleeve with the transmission seat and the dynamic ring, and then install the impeller and tighten the impeller back cap. The end cap can only be installed after the pump body is installed.

And for double support centrifugal pumps, the impeller is already installed inside the pump body when the seal is installed. Insert the shaft sleeve, dynamic ring assembly, and end cap with static ring onto the shaft, and install the bearings at both ends. Only when the rotor is in the working position can the mechanical seals at both ends be installed. Before tightening the end cap bolts, check whether the compression of the seals at both ends is appropriate.

The fit and pressure ratio of each part of the containerized mechanical seal have been adjusted before leaving the factory, so do not open the dynamic and static rings of the mechanical seal to readjust the compression amount of the elastic element. During installation, simply clean the entire device, as well as the sealing chamber and shaft, to install the entire sealing device into the sealing chamber. Tighten the sealing end cap bolts and shaft sleeve fastening screws. Containerized mechanical seals are generally designed with a positioning device (limit block) at the static ring seat and shaft sleeve. Before the equipment is operated, the positioning device must be loosened, otherwise the mechanical seal will burn out instantly.

（2）Precautions for installation of mechanical seals for kettles

The installation sequence of mechanical seals for kettles is basically the same as that of mechanical seals for pumps, but corresponding installation methods should also be adopted based on the structural characteristics of the reaction kettle itself and the selected mechanical seal structure form. Taking the single end external mechanical seal as an example, this article introduces the precautions for its installation and use.

a.Reduce the radial runout of the mixing shaft

Due to the fact that the fulcrum of the mixing shaft is generally at the upper part, the cantilever part is longer, and the lower part is far away from the support, the radial runout of the shaft is relatively large. When using soft packing for sealing, the packing itself acts as a fulcrum, providing a certain degree of support. After removing the packing and using a mechanical seal, this pivot point is eliminated. Therefore, some old equipment often encounters the problem of excessive radial runout of the shaft when using a mechanical seal, sometimes reaching2～3mmEven bigger. In this case, if the mechanical seal cannot function properly, the following measures can generally be taken:

Add intermediate bearings as shown in the figure11-12As shown, add an intermediate bearing in the middle of the reducer bracket. The closer this bearing is to the installation position of the mechanical seal, the better (but it should not affect the installation and removal of the mechanical seal). When the original bracket cannot meet the requirements, the bracket should be replaced again. Usually, the ratio of the distance from the reducer bearing to the intermediate bearing to the distance from the intermediate bearing to the lower end of the mixer is requireda/bFor（1：4）～（1：5）. When the stirring shaft speed is high or the shaft diameter is large,a/bThe value should be reduced, and if necessary, several sets of intermediate bearings should be added.

Add the flange at the mouth of the kettle as shown in the diagram11-13The anti swing sleeve shown. This method has a simple structure and is often used when modifying mechanical seals in equipment. The material of the anti swing sleeve should be determined according to the equipment and medium conditions. Enamel pots often use polytetrafluoroethylene materials, while general pots can be made of materials such as bronze.