ZTS Valve from KSB
Supplying the Full Range - From Pumps to Valves
In addition to valves for the ASME and API markets, KSB also supplies a full range of high and low pressure gate, globe, check, ball, and diaphragm valves designed to ISO and EN standards. The latest focal point of the KSB Valve portfolio is the ZTS Gate Valves with Pressure Seal Bonnet. The hammer forged steel body of the ZTS Gate Valve, is able to handle water, steam, gas, oil, and other non-aggressive fluids. It mainly operates for the applications including, industrial, power stations, and process engineering systems.
Trends in the New State of the Art Fossil Power Plants
In an effort to increase sustainability, there have been more and more demands upon power plants, and the new technologies being installed. New trends now demand that plants increase efficiency and reduce CO2 emissions. In accordance with demands, KSB believes offers a product to help meet the requirements of developing zero-emission power plants with 3 main valve features. The ZTS offers customers several technical advantages to ensure performance and reliability. To detail the design, let us focus on the following areas: Sealing to the Atmosphere, Internal Sealing, and a More Robust Body Design.
Sealing to the Atmosphere
A major component of the ZTS Valve is method used to seal the process fluid off from the atmosphere. With a confined graphite gland it offers a primary advantage of no creeping of packing into the clearance between the stem and body which ensures low risk of leakage and longer service life. This sealing is very reliable especially at high pressure/temperature ratings. The flexible stainless steel caps protect the pure graphite from oxidation above temperatures higher than 1000 degrees Fahrenheit, which also increases service life and reduces the risk of leakage. In addition, there is an installed compact, principle pressure seal bonnet that helps the valves sealing properties when it is under higher operating pressure. As a final safety precaution, the ZTS is equipped with a pressure relief valve that comes into effect when pressures reach critical levels. Such a design allows flow within the valve to go in either direction, and still provide pressure relief.
The standard for KSB’s gate valve design is the double wedge holder. The double wedge design allows the wedge halves to not be subjected to any additional actuating moments. This helps to avoid additional loads on the seat/disc interface. The ZTS valve ranges are also available as parallel disc gate valves. This design offers precise guidance of discs between parallel seats during stroke which results in no vibration. Instead of a ball segment, the parallel discs are supported by replaceable disc springs with a parallel pin. The springs serve to press the parallel discs against the valve body seats to help against temperature and pressure fluctuations.
Due to high operating temperatures, the Valve Body Design is under constant innovation. Recently, KSB has developed a hammer forged valve body design that is very advantageous to its valve portfolio. This design is a very fine-grained, homogenous material structure which is extremely robust, capable of withstanding high stresses. This makes the ZTS ideal for the highest pressure and temperature ratings. As compared to cast steel, the forged body is not vulnerable to pores and pitting and contains a very weldable, strong surface.
ZTS, Degree of Separation
In order to meet the high temperatures and pressures of high efficiency power plants, KSB has developed new P91 and P92 material executions in order withstand the high heat. These materials have the advantage of a reduced wall thickness, decreasing the valve’s weight and allowing for a short start-up and shut-down period in the power plant. Another new feature is the Ball-Gate Valve design, which is only manufactured by KSB. This innovative design has many features which separates it from the older cube design. Due to the spherical body, the Ball-Gate Valve has uniform wall-thickness and ideal pressure distribution. In turn, thermal stresses are reduced during the start-up process, relieving pressure on the valve. This creates a shorter start-up and shutdown period, as well as longer creep resistance.