The HARTMANN VALVES GmbH opens new application areas with its individually developed ball valves. The company's 12 inch PN 50 ball valve that is designed for use as a control and regulation valve in the petrochemical industry passed a long-term test of 100,000 switchings at 200 degrees Celsius.
In order to be registered as a supplier for a French state enterprise that licenses petrochemical plants, the Lower Saxon HARTMANN VALVES GmbH company contracted the long-term test on its 12 inch PN 50 ball valve in the summer 2011 out to an independent institute. At a switching time of 4 seconds, the valve was switched ON and OFF 100,000 times in this test with a drive specifically developed for this purpose. During the opening, which occurred within ten seconds, different opening angles had to be attained exactly because the ball valve is to be used as a regulator valve in later use too. The medium used was a solvent at approximate 200 degree Celsius. Tests were performed at a pressure of 50 bar and a differential pressure of 12 bar.
"This test environment is of course a combination of extreme conditions", says executive director Carsten Braun, who oversaw the development of the valve at Hartmann from the start. "A particular challenge is the fact that, because of the solvent as a medium, no greasing agent could be used." A challenge that the purely metallically sealing ball valve met superbly: Despite the small switching times, the high peripheral speed, high temperatures and high pressure, the seals were not etched away, nor was there wear worth mentioning.
"During the development we paid particular attention to the optimal material pairing of seating rings and ball", explains Braun the result. For many years Hartmann Valves has also developed and tested ball and seating ring coatings for the most different applications, both internally and with research partners such as Fraunhofer Gesellschaft für Schicht- und Oberflächentechnik (IST) (association for coating and surface technology) in Braunschweig and the TÜV Nord (technical oversight association),. The cooperation between the mid-level company from Lower Saxony and the Fraunhofer Institute has been particularly close in the development of torque-reducing coatings. With much success: It was possible to reduce torques by up to 50 percent. This saves costs with the drives.
From this point of view the good overall result of the independent long-term test is also the reward for intensive research work: one of the specifications, even after 100,000 switchings, was 100% seal tightness at a maximum angle offset of 3 degrees in the drive train (ball, operating spindle, drive) in reference to the fully opened position. The ball valve met these specifications and exceeded them: There was no measurable wear of the ball and the seating ring coating; no visible wear of the o-rings for external sealing. The supports of the ball was as new. In light of this finding no problems should be expected with 100,000 additional switchings - a number that is almost exotic in comparison with the number of switchings during "actual" operation.
With this test result Hartmann Valves GmbH reemphasizes its quality claim, which it has fulfilled as a family operation with by now 160 associates for 65 years. The company, located in Celle, manufactures and assembled completely „Made in Germany“. In the well head area - meaning the connection between subterranean oil and gas caverns as well as geothermal wells and the above-ground pipeline - it is the only supplier that is located in Germany in its entirety. The same stands for the previously introduced high-performance ball valve for petrochemical plants.
The ball valve is not yet well known in the petrochemical industry, and also not used much as a regulator valve. The intent is for the 12 inch PN 50 ball valve to change that, because the use of ball valves offers many advantages. For one, the pressure resilience is very good because the ball is more stable than, for example, the plate of a slider that is slid into the passage. During every activation the ball surface cleans itself. There are also no flow losses in the "fully open" position. And the On or OFF position is reached with a single quarter-turn, whereas in the case of sliders many turns are necessary. For this reason the ball valve is ideally suited for safety valves, because this quarter-turn can be implemented quickly with a drive. The option of also using the ball valve as a regulator has now become attractive and substantiated by the current test results. Up until now, if the ball was opened with a drive by about 20 degrees, it was indeed possible to regulate the flow ; but the edges that the flow would impinge on would wear, particularly in the case of gases with solid particle components that can reach supersonic speeds. This problem has been solved with the coatings by Hartmann Valves
Carsten Braun places particular emphasis on the customer focus of the company: "With a new construction we apply benchmarks comparable to custom-made suit. Each individual request of the customer can be considered. Up until now we have implemented every order, even at temperatures of -150 to +550 degrees Celsius". A strong suit of Hartmann Valves is also the area of pig valves that are used for the cleaning and testing of pipe lines. Product size here is from 2 to 36 inches. Part of daily business for decades has also been process valves for the petrochemical industry (high temperature, low temperature), quick-acting shut-off valves, cavern storage equipment, and geothermal projects. Hartmann Valves GmbH constructs and manufactures according to the set of rules of the API, Druckgeräterichtlinie (pressure equipment guidelines), as well as GOST. EON, RWE, Siemens, DOW and many others have been among its customers for many years.