The rapid development of control valve
2008-08-05

Suppliers reported big project wins in the oil & gas, refining, and petrochemical industries in the first quarter of 2008. Though the North American and European markets have slowed somewhat, suppliers are relatively immune, thanks to increased demand in developing markets, such as China, India, and the Middle East. Worldwide growth of energy production continued unabated through 2007. Global oil & gas companies continue to reap unprecedented windfall profits thanks to historically high oil price; even as exploration costs increase and international politics play a greater role. The value of oil has also caused oil & gas companies to work to improve their monitoring processes to prevent product loss and optimize production, which will require increased adoption of intelligent field devices, including control valves.

Control valves are valves used within industrial plants and elsewhere to control operating conditions such as temperature, pressure, flow, and liquid level by fully or partially opening or closing in response to signals received from controllers that compare a "set point" to a "process variable" whose value is provided by sensors that monitor changes in such conditions. The opening or closing of control valves is done by means of electrical, hydraulic or pneumatic systems. They are the most common final control element in the process control industries. Many people who talk about control valves or valves are really referring to a control valve assembly. The control valve assembly typically consists of the valve body, the internal trim parts, an actuator to provide the motive power to operate the valve, and a variety of additional valve accessories, which can include positioners, transducers, supply pressure regulators, manual operators, snubbers, or limit switches. A control valve for controlling the flow of fluent material from a machine, the machine having a frame including a hopper and a tube mounted to the hopper, an auger within the tube and a hose mounted to the tube. The control valve has a clamp, which has a first arm mounted to the frame on a first side of the hose and a second arm mounted to the frame on an opposite side of the hose. The first arm is movably mounted to the frame in a direction toward the hose. A prime mover is drivingly linked to the first arm and the frame for displacing the first arm toward the hose, thereby clamping the hose between the first and second arms for restricting the flow of fluent material through the hose

. There are many types of control valves. Among these various types, there are the globe, knife or gate, needle, butterfly, ball, pinch, diaphragm, and the ball valves. The gate or knife valves are the most common among all the control valve types. In this case, a flat closure device will slide into the liquid flow stream, to shut it down. There are two types of gate control valves. These are the parallel gate valves, which use a flat disc in form of a gate, between the seats, and the wedge-shaped valves. Also, the diaphragm valves are very familiar and easy to use. These valves ca separate the flow stream from the closure element. These valves are a little bit like the pinch valves, except the fact that they don't pinch the liner in order to shut it off, they simply push a diaphragm at the bottom of the valve body, to provide shut-off. The needle control valve, as its name suggests it, has a tapered, slender point at one end of the valve, which is lowered in order to block the liquid material flow. The stop-cock valves, also called plug control valves, are probably the oldest valves used by our society. History says that even the Romans used it. Today, the cock valve remains the most common type of valves, and it is used all around the world. The things that make it so common are the affordable cost, and the use of both sequences of the throttling process. All these types of valves are used in sanitary, irrigation, gas or air, refrigeration, medical and other various applications. The worldwide control valve market enjoyed yet another year of historic double-digit growth between 2006 and 2007. Strong revenue growth is expected to continue at a compounded annual growth rate (CAGR) of 6% over the next five years. The market reached $4.8 billion in 2007 and is forecasted to exceed $6.4 billion in 2012, according to a new ARC Advisory Group study. In terms of growth, control valves market is forecast to outpace all other categories of industrial valves. Massive investments in gas & oil sector and rise in the number of Greenfield plants constructed in developing countries is driving the growth of control valves market.

To most control valve suppliers despite strong growth opportunities, challenges still remain. While the extremely robust growth occurring in developing markets provides control valve suppliers a tremendous opportunity to grow their business, establishing a global supply and logistics system and designing new products for the changing needs of the global control valve market, are key challenges control valve suppliers must overcome.

The ability to guarantee delivery times is more difficult now than ever before as demand for control valves continues to increase from developing markets around the globe, and many control valve suppliers face manufacturing constraints. To ensure strong global delivery and service capabilities, control valve suppliers are finding it necessary to invest heavily in manufacturing and project engineering capabilities throughout the globe, with a particular focus in developing markets. On the supply-side of the equation, long-term agreements with foundries in North America, Europe, and Asia remain critical to protect needed capacity and lead times. Those suppliers who did not establish long-term agreements with foundries during the lean years were not prepared for the strong surge in demand and are finding it difficult to secure the valve castings necessary to meet demand.