Triple offset fully metal-seated bi-directional butterfly valve with zero leakage takes use of the most advanced technology in the worldwide butterfly valve field.
Lotoke butterfly valve performance advantage is mainly reflected as follows:
Bi-directional pressure bearing----- The analysis of optimization of three eccentric parameter through self-developed design software, with the measures to improve main components’ geometric and dimension tolerance accuracy to achieve Lotoke butterfly valve bi-directional pressure bearing and arbitrary flow installation.
Overall metal forged valve sealing ring and seat-----The sealing ring and seat use overall metal forged crafts with all sprayed Stellite or various sealing material that’s more suitable for working conditions. After Stellite sprayed, the sealing components can be abrasion resistance, anti-erosion, longer service life with high sealing performance to achieve zero leakage.
On-site replaceable sealing components-----The sealing ring and seat can be replaced by dismantled from the valve with no need to disassemble the whole valve. This achieves rapid on-site maintenance and makes the valve’s service life parallel to that of the pipeline so that directly reduce production and equipment maintenance costs.
Lotoke butterfly valve is suitable for various complex medium and working conditions——Lotoke butterfly valve can endure high pressure and high temperature up to 850℃, low temperature to -196℃. And it’s safety under the condition of various pressure up to 2500LB and bi-directional pressure bearing up to 600LB.
1.1 Application Standard
Lotoke Butterfly primarily using the following standards
ASME/ANSI B16.34 Valve-Flanged，threaded and welding End
ASME/ANSI B16.5，ASME B16.47 Pipe Flanges and Flanged Fittings
ASME/ANSI B16.25 Butt-welding Ends
BS6364 Specification for Valves for Cryogenic Service
API 609 Butterfly Valves : Double-flanged, Lug-and Wafer-type
API 607 Fire Test for Production Pressure Testing Requirement
API 598 Valve Inspection and Test Standard
ASME B16.10 Face to Face and end to end dimensions of valve
MSS-SP-25 Standard Marking System for Valves，Fittings，Flanges and unions
1.2 General Technical Requirements
1．Choose the correct type according to the Technical Specifications, Lotoke can ensure the correct valve type selection as per the design requirements.
2．Valve leakage rating: According to the specifications requirements, during opening and closing, the leakage rating is not less than class VI.
1.3The main features of Lotoke butterfly valve：
1 Bi-directional same pressure bearing capacity which achieves no flow restriction installation.
2 Fully-metal sealing design with sealing surface sprayed Stellite alloy which solves the poor sealing performance problem under various harsh working conditions like high pressure, high and low temperature.
3 The so-called three eccentric means adding a corner eccentric on the basis of double eccentric structure which makes the sealing surface of butterfly valve into oblique cone shape. The feature of this structure is to process the outer periphery of the disc into oblique cone and process the inside of the sealing seat into internal oblique cone. Then the seal section of butterfly valve becomes oval shape therefore the disc sealing surface becomes vertical asymmetry. Since the sealing surface is in oblique cone shape, separated by the shaft axis, the larger side of disc slant along bigger inclined surfaces upward to press the valve seat while the smaller side of disc slant along smaller inclined surfaces downward to press valve seat. Sealing between disc seal ring and valve seat is not by elastic deformation of the valve seat, but entirely on the pressing of the contact surface to achieve sealing. So the opening and closing of triple offset butterfly valve is frictionless and with the increase of closure pressure, the valve is closed more tightly. Seen from the structure principle of triple offset butterfly valve, the following advantages can be easily generalized. ：
- Good sealing performance which increases the reliability of the system
- Small friction, save effort when opening and closing and flexible
- Longer service life and can achieve repeatedly open and close.
- Pressure-bearing and high temperature resistance capability ensure its wide application.
The Triple Offset Geometry
Offset 1. The shaft is offset behind the seat axis to allow complete sealing contact around the entire seat.
Offset 2. The shaft centerline is offset from the pipe and valve which provides interference free opening and closing of the valve.
Offset 3. The seat cone axis is offset from the shaft centerline to eliminate friction during closing and opening and to achieve uniform compressive sealing around the entire seat.
4 The design of replaceable valve seat and sealing ring which can reduce the cost of use by not discarding the whole valve when the problem that sealing abrasive occurs.
5 The difference between Lotoke fully metal-seated butterfly valve and multi-layer sealing butterfly valve is that the construction of multi-layer metal sealing structure is laminated by metal flake and graphite flake and it’s easily eroded by the fluid so that the service life will be shorter. However, Lotoke butterfly valve takes advantage of the construction of fully-metal stainless steel forged sealing ring with sealing surface sprayed Stellite alloy whose advantages are anti-erosion, longer service life and abrasion resistance which can endure various harsh working conditions like high temperature and high pressure.
Multi-layer Metal-Seated Sealing Lotoke Fully Metal-Seated Sealing
6 The difference between Lotoke fully metal-seated structure butterfly valve and U-type ring sealing butterfly valve is that the U-type ring sealing butterfly valve achieves sealing through seal resilience. After the failure of elasticity, the design defects like weak hardness of the sealing surface and poor anti-abrasive performance all result in inner leakage, shorter service life of the butterfly valve which causes its less adaption in certain working conditions. While Lotoke fully metal-seated butterfly va lve can completely solve this kind of problems.
The main characteristic of Lotoke triple offset butterfly valve is a fundamental change in the sealing structure. It’s no longer position sealing, but torque sealing. That means it is not relied on the elastic deformation of the valve seat, but totally depended on the contact surface pressure of the valve seat to achieve sealing effect. Therefore, it solves zero leakage problem of metal-seated butterfly valve.
The design of the sealing angle solves the problem that positive and opposite of medium pressure all work on sealing surface. By contact surface pressure and part of medium pressure working on the sealing surface smoothly solve the sealing surface high temperature resistance problem.