Edwina Dorsey Valves April 14th, 2019 - 12:32:49
A valve is a device which controls the flow rate, pressure or the direction. The controlled fluid can be the liquid, gas, the mixture of gas and liquid or the mixture of solid and liquid. The valve usually is composed of body, seat, bonnet, parts for opening or closing, actuating device, sealing element and so on. The controlling function of the valve depends on the actuating device or the movement of the fluid which drives the sliding, rotating or turning of the parts for opening or closing to change the area of the flow passage.
Ball valves are usually quarter turn valves (as we turn the lever by 90 degrees to start or stop the flow) and use a hollow, perforated and pivoting ball that is also called as a floating ball. It is through this valve that the flow of fluids takes place. When the lever or handle is turned to 90 degrees, the hole of the ball gets aligned with the pipe opening and starts the flow. When again the lever is turned by 90 degrees, the hole turns around and the ball blocks the opening of the pipe thus causing the flow to stop.
Among the many types of Valves manufactured by Swagelok, are Ball Valves - these are used where flow needs to be completely shut-off. They have advantages over many other types of Valves in that they are easy to use, easy to maintain, and can regulate high-pressure, high-volume and high flow of temperature. They are uncomplicated, sturdy, and inexpensive; they lend themselves to a long service life. Swagelok has a full catalogue of various types of Ball Valves. For all the advantages of Ball Valves, they are not suitable for use where fine control of a Valve is needed. Depending on system requirements, in these circumstances, a Needle Valve may be appropriate - these allow for a range of flow, and can control flow into delicate gauges where sudden surges of pressurized fluid can cause damage. They can also be used where flow must be precisely and gradually brought to a halt. Needle Valves are not suitable for simple shut-off applications as are Ball Valves - they should be used where a small rate of flow is required.
The formula for the theoretical length of tubing, TL, needed to lower a set number of half steps, x, for an instrument of length, L, is TL = L (16/15) ^ x. Example: 100" instrument lowering 3 half steps: TL = 100(16/15)^3. TL = 21.36.
With the advent of the market brass ball valves, they immediately appreciated was evaluated, and the demand for these products increases, as well as their scope. Now such products can be found in any economic stall. However, despite their apparent similarity, not all ball valves are really reliable and durable. Along with high-quality Italian taps, more and more pushed over in the trade cheap Polish, Chinese and Turkish valves, whose quality is far from perfect? In the struggle for the vast US market, some sellers have begun to distribute cheap "consumer goods" for branded products, quite simply to sell a fake, so I'd like to give some practical advice to buyers' brass ball valves. As a rule, forgery in performance is much inferior to the original products. Their use in water and heating systems can lead to accidents and big material losses. Counterfeits can cause serious damage and human health.
Needle Valves are designed in many different materials. The valve is generally metal - here stainless steel, or a steel alloy, brass, or bronze are most often used, The seat is usually made from an elastomeric material such as PVC, CPVC, PTFE or a suitable type of the wide range of plastics and thermoplastics on the market. Valves are available in different materials - here customer choice will be determine by the specific application the valve is to be used for, along with the conditions it will be subject to. You have to take into account whether the fluid is particularly high or low in temperature, likelihood of corrosion, and how much wear the valve will be subject to you. Swagelok will be able to consult with you, and advise you what type of valve is best for the application you require it for. Swagelok Tube Fittings are available in additional Valve Body Materials on request - these include carbon steel and 25Cr super duplex stainless steel.