German dwi seals dwi models dwi prices

dwi seals are devices that prevent fluid leakage, consisting of at least one pair of faces perpendicular to the axis of rotation. These faces remain in contact and slide relative to each other under the action of fluid pressure and the elastic force (or magnetic force) of a compensation mechanism, along with auxiliary seals. Mechanical seals where the elastic loading mechanism and auxiliary seal are metal bellows are called metal bellows seals. In light-duty seals, rubber bellows are sometimes used as auxiliary seals; however, since the elastic force of rubber bellows is limited, springs are generally required to supplement the loading force. Mechanical seals are commonly referred to as "mech seals".

Function of dwi seals

Prevent high-pressure liquid from leaking out of the pump and prevent air from entering the pump. Although the shaft seal occupies a small space in the pump, the normal operation of the pump is closely related to the shaft seal. If the shaft seal is improperly selected, it will not only require frequent maintenance during operation and cause significant loss of the conveyed liquid, but may also cause fire, explosion, and poisoning accidents due to the leakage of flammable, explosive, and toxic liquids, with unimaginable consequences. Therefore, the shaft seal structure must be reasonably selected to ensure the safe operation of the pump. 1) Since the pressure inside the cylinder is not equal to the external atmospheric pressure, steam inside the cylinder or air outside the cylinder will inevitably leak out or in through the radial clearance between the main shaft and the cylinder, causing working medium loss, deteriorating the operating environment, and heating the shaft journal or allowing steam to enter the bearing housing, causing oil deterioration. Air leakage also destroys the vacuum, thereby increasing the exhaust load, which reduces unit efficiency. For this reason, shaft seals are installed where the rotor passes through both ends of the cylinder. This type of shaft seal is called an end shaft seal, abbreviated as shaft seal. High-pressure shaft seals are used to prevent steam from leaking out of the cylinder, and low-pressure shaft seals are used to prevent air from leaking into the cylinder. 2) During turbine operation, a portion of steam will inevitably leak from the shaft end to the atmosphere, causing loss of working medium and heat, and also affecting the working environment of the turbogenerator. If adjustment is improper and steam leakage is excessive, it will cause the temperature of bearings near the shaft seal to rise or water to enter the bearing oil. For this reason, shaft seal heaters are installed in various units to recover and utilize the shaft seal steam leakage from the turbine. 3) Prevent steam inside the cylinder and valve stem leakage from leaking outward, polluting the turbine room environment and bearing lubricating oil quality. Prevent high-temperature steam from flowing over the turbine main shaft during normal unit operation, causing it to heat up and thus causing bearing overheating. Prevent air from leaking into the vacuum part of the cylinder. Ensure the vacuum effect and degree of the condenser during unit startup. Recover shaft seal and valve stem leakage to reduce working medium and energy losses. 4) During turbine tripping shutdown and the entire hot shutdown process where the condenser needs to maintain a vacuum, prevent air from leaking into the turbine, which would accelerate internal cooling of the turbine and cause main shaft bending.

dwi seal replacement steps

1) Remove the main pulley (belt drive) and remove the key pin; 2) Use a pin puller to remove the locating pins of the shaft seal end cover; 3) Remove the fixing screws of the shaft seal end cover; 4) Use a circular external puller to remove the shaft sleeve (if no puller is available, cut a groove on the shaft sleeve with a cutting machine and knock it off with a chisel; note: use something to block sand to prevent it from getting into the screw rod); 5) Remove the old shaft seal; 6) Clean the shaft seal end cover and bearing positions, then clean with 755; 7) Apply 638 adhesive to the shaft seal installation position, then carefully install the shaft seal; note: do not damage the rubber lip; you can apply a little oil or high-temperature grease to the rubber surface of the shaft seal; 8) After cleaning the shaft sleeve position, reinstall and fix the end cover securely (you can wrap a layer of thick glossy paper around the shaft to prevent the shaft seal lip from accidentally touching the keyway during end cover installation); 9) Clean the new shaft sleeve and installation position, apply fixing adhesive 638 to the inner circle of the shaft sleeve. Cold fit: Use a forcing bar to evenly knock the shaft sleeve in; pad the outside of the new shaft sleeve with an outer ring of the same size to avoid damaging the shaft sleeve. Hot fit: Clean the inside of the shaft sleeve thoroughly, ensuring no oil. Apply a ring of 638 glue to the shaft journal before the shaft seal, heat the shaft sleeve to 110 degrees, and install it. (Note: Push the shaft sleeve to the edge of the shaft seal, pause briefly. Wait for the temperature to drop before pushing it into the shaft seal position; 10) Install the pulley or coupling, correct parallelism or centerline, and manually reverse the machine head to allow lubricating oil to return to the front bearing and shaft seal.

Technical requirements for dwi seal installation

Mechanical seals are high-precision mechanical components, and their correct installation and operation have a significant impact on their service life. We generally follow the standards specified by the Ministry of Petrochemical Industry. The technical requirements for the pump installing the mechanical seal and the parts mating with the mechanical seal are as follows: 1) Shaft bending: maximum not greater than 0.05 mm; 2) Rotor runout: near the shaft sleeve at the rotating ring seal ring, not greater than 0.06 mm; 3) Axial movement of the shaft must not exceed ±0.5 mm; if a shaft sleeve is present, the shaft sleeve must not be loose; 4) Coupling alignment error: for gear couplings, not greater than 0.08–0.10 mm (P2008C); for elastic couplings, not greater than 0.05–0.06 mm; (common practice: axial runout<0.05, radial runout<0.10) 5) The concentricity tolerance of the gland (static ring seat) mating spigot with the shaft centerline is 0.05 mm, and the perpendicularity tolerance of the plane contacting the gasket to the centerline is 0.03–0.05 mm. If requirements are not met, the seal chamber must be machined; 6) The ends of the shaft sleeve where the rotating ring seal ring is installed, and the ends of the gland (or housing) where the static ring seal ring is installed, should be chamfered and smoothed. 7) Be careful when installing and removing mechanical seals; strictly prohibit the use of hammers and flat chisels to avoid damaging seal elements. If scaling prevents removal, clean thoroughly before disassembly. 8) If mechanical seals are used at both ends of the pump, take care during assembly and disassembly to avoid neglecting one side while attending to the other. 9) For mechanical seals that have been in operation, if gland loosening causes seal movement, the rotating and static ring parts must be replaced and should not be retightened for continued use. Because after loosening, the original operating trajectory of the friction pair will change, and the sealing performance of the contact surface is easily compromised.

Weidou Intelligent Technology professionally sells German dwi seals, dwi sealing rings, dwi sealing strips, dwi pipe seals, dwi cable seals, dwi rubber seals, dwi mechanical seals, dwi sealing gaskets, dwi oil seals, dwi shaft seals, dwi metal seals, dwi high-pressure seals, dwi spiral seals, dwi centrifugal seals, dwi sealing rings, dwi original German imports. Welcome customers to inquire and order.