“T” Series Power Ball Valves – The Ladish Way (download the full catalog here)
While the Ladish Metal Seated Ball Valve for Power is relatively new to the market, the engineering, design principles and team members’ expertise behind this valve are well established. The Ladish team collectively brings over 100 years’ experience to the design and application of Metal Seated Ball Valves.
Over the past 30 + years, the Metal Seated Ball Valve has found wide applications in the Thermal Power Generation industry as well as in steam and high energy applications in Refining, Chemical, Paper and other industries. Over the years, the performance and reliability requirements have grown more rigid as have the quality standards expected of the manufacturers. It is now required that these valves provide tight shut-off capability along with the ability to function through severe thermal cycles. The development of the Ladish valve used these requirements as a basis and added modern requirements of low emissions, sustainable manufacturing technology and ease of automation.
Existing Severe Service Metal Seated Ball Valves in the Power Market generally fall into two basic designs.
- The first and most common is the “Inserted Seat” where the ball and replaceable seats are coated then “mate” lapped together with the seat either being loose or pressed fit into a valve body. The concept is to utilize the same seat and ball material for thermal matching but leaves a vulnerability of leakage behind the inserted seat as the body material is typically different from the trim. This secondary leak path is difficult to control and limits the ability of these valves to provide tight shut-off.
- The other less common design utilizes what is commonly referred to as an “integral seat”. In this design the primary seat is machined into part of the valve body and the coated ball is then lapped into that seat. This is advantageous in that there is no leak potential behind the seat. The disadvantage is that the ball and seat are usually different materials and not thermally matched. This results in leakage as valves go through the routine thermal cycles.
Considering the damage quickly caused by either leak mechanism, there is clearly opportunity for a new and better design like the Ladish “T” Series!
The major design feature of the “T” Series is the “Captured Flange Seat” which addresses the issues above. This design incorporates the desirable feature of a replaceable seat thermally matched with the ball, and then “clamps” the foot of the seat between the two halves of the valve to eliminate the secondary leak path. This new Ladish design includes the good attributes of others while eliminating the most common causes of valve failure. To further improve reliability and sealing performance, Ladish does a 360o seat-to-ball lapping process called FS (Full Surface) Lap. The fully automated Diamond FS process laps ALL of the ball surface to the seats preventing the “ridges” in older design valves that cause high torque in automated valves and routine coating failures.
While the proper design is critical, a key to valve reliability is the coatings used on the balls and seats. Apart from the fact that the coatings create a “bearing surface” that allows the valves to cycle without galling, it is the lapped coating that creates the seal. If the coating fails, the valve fails. In the Ladish “T” Series, we utilize an industry standard HVOF robotically applied Chromium Carbide Coating in our Class 1500 and 900 valves. However, for the Class 2500/3100 and above we will utilize a “Sprayed-and-Fused” Carbide Based coating that has many times the bond strength of the HVOF coatings, and is a better thermal match in the high energy valves.
The benefits to you are improved reliability and repeatable tight shutoff to all global standards.
- Available Sizes: 1/2” – 4”
- A105, F22, F91, F92 & others
- Available Classes: ASME 1500-4500 Limited Class
- Two-Piece Construction
- Available in: SWE, BWE, HUB-END
- Ball & Seat
– Standard: 410SS, HP-HVOF (Chrome Carbide Nickel Chrome)
– Optional: Inconel718 – Fused (Chromium Boride Chrome Carbide)
- Bore Sizes
– .65″, 1.00″, 1.50″, 2.00″, 2.50″ (1500, 3100, 4500)
– .65″, 1.00″ (4500)
Features & Design Attributes
Captured Flange Repairable Design – Tight Shutoff
360 Degree Lapping
Spray and Fused Coating on CL 2500 / 3100 and CL 4500
Two-Piece Design for SW & BW Preparation
Low Emission Design
Integral Actuator Mounting
Actuator Mounting Flanges
Ladish utilizes a rigidly secured mounting bracket for actuators, worm gears and levers. The bracket, constructed of heavy plate steel, is welded or bolted to the valve body. The mounting plate is parallel to the bore, and perpendicular to the stem, so there is no misalignment of the operator. Ladish places a heavy metal brushing in the bracket of the valve to guide stem and ensure that the stem does not experience lateral movement if subjected to side loads during operation. If side load occurs, it is absorbed outside the packing chamber and does not deform packing. Deformation of packing caused by side loading is a major cause of stem leakage in quarter-turn valves.
- Fully traceable to every heat & lot number for ALL inspections & fabrication points from receipt of raw material to shipment of final product.
- Fully integrated throughout local server for efficient distribution of records, procedures & documents.
- Documented corrections to any non-conformance with requalification testing recorded.
- Calibration control of all measuring & monitoring devices.
View our full quality control brochure here.
The term “Metal Seated Ball Valve” is widely used for this technology, but the ball and seat coatings that allow the valve to cycle without galling is the real heart of the valve. It is this same coating that is lapped for a Tight Shut-Off and must resist chemical and thermal attack from the process in which the valve is installed. The key to the reliability of the valves in your process is the selection of the right coating for your application, and Ladish engineers are expert in assisting with that selection. Some of the more standard options offered are:
- Spray & Fused – The ball and seat surfaces are coated with a relatively thick layer of hardening material, then the part is heated to “fuse” (similar to welding) the coating to the base material for the highest possible bond strength and lowest porosity.
– Complex Carbides and Borides
– Nickel / Cobalt Based Materials
- HP-HVOF Process – Ladish utilizes a robotically controlled “gun” which applies the coatings at a velocity and energy level that creates a mechanical bond with the base metal.
– Chromium Carbide with Nickel, Chromium or Cobalt Binders
– Tungsten Carbide with Cobalt or Nickel Binders
Once again, Ladish will continue To Mark Progress.