But this situation will not cause manufacturers and dealers of high-pressure valves any major headaches. There are just too many ways to use them. That is why AS-Schneider designs high-pressure valves for measurement and control technology applications in a wide range of sectors, including chemical and petrochemical plants and the crude oil and natural gas industries. “Pressures here can often reach several thousand psi (several hundred bar), and the process media can be aggressive and harmful to people and the environment,” the company explains. Most valves very quickly reach their limits under these conditions.
Variable modular design
This is how the high-pressure valve is designed: the spindle sealing (packing) is made from the polymer PTFE. “Furthermore, the high-pressure valves benefit from a metallic rear seat, which provides an additional seal against the outside environment, reducing the demands on the packing,” according to AS-Schneider. This results in both reduced wear and in the valve being blow-out proof.
The modular design allows many configuration options for the high-pressure valves in terms of function, material choice, type of connection and application area, explains Göpfert AG. In addition to shut-off valves, examples include control valves, non-return valves, strainers, valves for panel mounting, valves with cutting ring fittings or with welding ends, and valves with an external spindle thread. “As well as traditional hand wheel operation, our high-pressure valves can also be fitted with actuators for use as automated valves,” the company states.
The tightness is also important, Bürkert adds. The pre-controlled valve with servo piston and two way pre-control has an additional radial seal and “enables very good tightness”, according to the company. The high pressure design covers pressures up to 250 bar.
Fossil and nuclear power generation
Schroeder Valves is active as a manufacturer of high-pressure valves in the areas of fossil and nuclear power generation, as well as descaling in steelmaking. The company’s high pressure range starts at the PN250, or class 1500 lbs, pressure rating. In classic (minimal flow valve) applications, this corresponds to operating pressures from approximately 140 bar, and goes up to approximately 400 bar. There are even application areas for high-pressure valves with operating pressures of several 1000 bars. The materials typically used in Schroeder Valves’ application areas are hardened martensitic steels.
“For minimal flow valves, the classic application is in the boiler feed water areas in fossil fuel and nuclear power plants, where to increase efficiency, the water is first brought to a high pressure before it is vaporised by the addition of heat and discharged through a turbine,” owner Axel Mücher explains. Other fields of application are the descaling of rolled metal in steelmaking, which involves using a high pressure water jet to blast the unwanted scale layers off the steel, and water injection, whereby high pressure water is injected into an oil or gas field to increase the pressure inside the well and thus increase the flow rate.
Weight reduction as a target
Particular situations require special measures: high pressures cause very high forces on the walls of the pressurised parts of a valve, which in itself requires a thick construction. “The amount of material used and weight reduction therefore play a role for purely cost-based reasons,” says Mücher. Therefore, in terms of the geometrical design, one tries to enclose the pressurised volume in the most efficient and material-saving way.
One must also remember that valves must be integrated into pipelines, where their weight sometimes causes high operating forces, which must be borne by appropriate supporting structures. Mücher continues: “Any possible material-efficient design is also in the interests of the user here.”
Users therefore pay close attention to quality, costs and criteria such as weight reduction. Manufacturers of high-pressure valves who do not want to come under pressure themselves must prepare for this. Then your business can run at full speed. Innovations in the fields of valves and associated products will be presented at the world`s no 1 fair for industrial valves, VALVE WORLD EXPO, from December, 1-3, 2020 at Düsseldorf Fairgrounds.