Amie Brewer Valves April 20th, 2019 - 12:38:50
Two thousands years ago, the Chinese people applied the bamboo trunk and wooden plug into water pipeline. Then later they applied the sluice into the irrigational canal, the plate check valve into bellows for smelting and so on. With the development of smelting process and hydraulic machinery, the plug valve made of brass and lead appeared in Europe. Besides, with the wide application of boiler, in 1681 the safe valve with lever and heavy bob came into the world. Before the invention of the Watt steam engine, the plug valve and check valve were the most important valves. The steam engine leaded the valve into a new field namely mechanical industry.
These examples of Swagelok Valves give the customer great insight into the care, detail, quality, design and testing that goes into the manufacture of each and every Valve in the Swagelok catalogue. It's easy to see why Swagelok has no hesitation in backing their products with the Swagelok Limited Lifetime Warranty.
The 4th valve solves some problems and adds others. The 4th valve adds 38.08 inches of tubing in the case of our 100" instrument. This is a substitute for the 1-3 combination as the 4th valve has the correct amount of tubing to be in-tune. Likewise, the 4-2 combination produces a pitch more in-tune than 1-2-3 as it only lacks about 2.54 inches of tubing from the theoretical length. So this is great, now we have all of the seven common combinations relatively in tune right? This is true, however, this 4th valve grants access to a range which three valve instruments cannot reach. When using combinations with the 4th valve, euphoniums can reach notes such as D below the staff, a note which is not possible using three valves. Now we get to the curse of the 4th valve. When using the 4th valve in combination with other valves to reach these low notes, the problem described above compounds on itself even further. To lower the pitch a whole step after depressing the 4th valve, 19.02" must be added in addition to the length of the 4th valve. Generally, the first valve would lower the pitch by a whole step, but remember the length of the first valve tubing? 13.77 inches. Again, this problem compounds as more valves are depressed. Using the 1-2-3-4 combination, which using the half-step definitions of the valves, should provide a B natural a half step above pedal Bb. However, the length of tubing for a low B natural is a whopping 203.38 inches! The combined length of all four valves only equates to 173.22 inches... Thats only enough for a slightly sharp C! Thats right, that means that B natural is not possible (without lipping from the performer) on a non-compensating 4 valve euphonium.
The second type is a product with override control to stop flow regardless of flow direction or pressure. It can not only close in response to backflow or insufficient forward pressure, but also can be deliberately shut by an external mechanism, thereby preventing any flow regardless of forward pressure.
Industries demand product quality, reliability and innovation, none more so than in the performance and reliability of manual operated valves. The effectiveness in operation and the production ability of industrial giants is, in many ways, dependent on seemingly insignificant valves, one specifically being the control pinch valve.
The first category is the most common one. A ball in the shell of the valve fits tightly against the side of the valve where the water comes in. Water pushing through the pipe moves the ball against the spring, allowing water through the valve. When the water is turned off, the ball is pushed into place by the spring and keeps water from flowing backward through the pipe.