Valve Design Details Give Swagelok Manifolds an Edge
by Taryn Hardes, on Mon, Apr 15, 2013 @ 09:04 AM
The non-rotating ball tip utilizes a ball flat bearing on top of the ball that allows smooth axial rotation and prevents undesirable transverse rotation
Patented non-rotating ball-tipped
Download our catalogue for more
Some Swagelok products are simple, such as tubing. Some are complex, such as regulators. Then there are products such as our manifolds, which look complex but are really rather simple. They are basically blocks of steel with holes in them, controlled by a series of stainless steel needle valves, to control flow. The valves may block pressure, bleed off pressure or equalize pressure, depending on their location. We offer them in designs with two, three and five valves. The two-valve models are for static pressure and liquid level applications. The three- and five-valve models are for differential pressure applications. A three-valve manifold is typically used in liquid measurement, whereas a five-valve manifold is used for gases.
Design & capabilities
The three-valve manifold was introduced way back in 1910, but the design was ahead of its time for the machining technology available. The equalizer valves often leaked, and the resulting measurement error could be costly. By 1960, however, designs and manufacturing capability had improved. That's when the force-balance pressure transmitter was developed, a device that makes sure that pressure is not building up beyond safe levels. The industry standard now is Emerson's Rosemount 3051 pressure transmitter, and Swagelok manifolds work with it very well. Pressure transmitters aren't cheap. Don't make the mistake of trying to get back some savings by getting a cheap manifold. It's would be like buying an expensive stereo system and then hooking it up to cheap speakers. You won't get the performance that you paid for. Likewise, a good manifold is crucial to top performance.
Swagelok improved the design even more for its manifolds with its ball-tipped needle valves. On any brand of manifold, when you turn the handle on the valve, it pushes the tip into another metal surface to create a seal. With ordinary designs, the tip rotates along with the shaft. As the tip is twisted, it can gouge the seat, creating leak paths. Swagelok came up with the idea of using a nonrotating ball as the tip of the valve. You can keep turning the handle and the stem to create tighter seal, but you will not damage the seat.
Swagelok also pays close attention to cleanliness. When the ports have been drilled out of the manifold, Swagelok uses a special machining process to remove all burrs. You won't have to worry about stray bits of metal damaging your instruments.
Swagelok has several series of manifolds. You can take a look at individual models, or the whole catalogue, online.