Worcester Control Valves

Transcription

1 TP-10D-1 How to Sell Characterized Seat Control Valves The Best Thing That Ever Happened to Control Valves Characterized Seat is a concept that can not be offered by anyone else but Worcester Controls. Like everything else, it will not be long before others find a way to duplicate our concept. So it is very important that we give it our best and promote the Characterized Seat Control Valve at customer level. Worcester characterized seat control valves represent a profound improvement over traditional globe and rotary valves that use heavy linear actuators, crank arms and associated linkages. Worcester has eliminated significant hysteresis and assured repeatability by powering through a solidly-clamped, in-line stem. All shafts operate together: actuator, positioner, valve stem. The design also eliminates side load on the valve stem because the components (valve, actuator, positioner) are mounted symmetrically and weights are balanced. This extends valve seal life far beyond conventional valves. The Way to Think Before you go on, please consider this: selling control valves is not the same thing as sizing control valves. If you can sell actuators, you can sell control valves! It takes a salesman to sell control valves, not an engineer. You must convince yourself that you CAN sell control valves. Even if you have never called on a customer to sell control valves, you first can be a productive salesperson if you THINK POSITIVE. Don t forget: during each call YOU WILL LEARN many things that add to your knowledge and you will keep getting better. Direct Shaft Position Feedback TABLE OF CONTENTS The Best Thing The Way to Think First Things First History Reccomended Product Specifications for Characterized Seat Features and Benefits Selection Actuation Locking Couplings Matched ball and stem connection NAMUR Interface

2 First Things First Selling control valves is like selling everything else, you must ask the following questions. Once these questions are answered, you will have a good idea what product to sell and which features to concentrate on. Who are your customers? In other words, who uses control valves? Almost anywhere you sell on-off valves, there is a need for control valves as well. If you are not sure, just ask if they have proportional control systems. Who are the contacts? This is the most important part of control valve sales. The one person that needs you is the one who is involved with the control valves on a daily basis. The person is in the instrument shop. Unlike the on-off valves, which maintenance people usually handle, the control valves fall into the instrument category. The Instrumentation Technician is the one who can tell a good thing when he sees one. He knows what works and what does not. This makes the selling much easier. Once you have covered the instrumentation shop, the next level to contact would be the instrument engineering people. They usually learn most of their practical education from the instrumentation shop people and therefore usually listen to recommendations from the shop. These engineers are concerned with sizing control valves. What control applications do they have? Modulating control applications (proportional and throttling), regardless of the media, are flow, temperature, pressure, level and Ph. What are they using currently? Traditionally, globe valves have been used for proportional control applications. In applications where solids are present, the user s choice changes. Ball, plug, butterfly and even diaphragm valves are preferred. Why are they using the existing valve style? When we talk proportional control, we are referring to a loop where a variable is changed to a constant. To do this, the excess loop energy is dissipated in the system and absorbed by the control valve. Globe valves, with all metallic components in their waterway, are designed for this purpose. They can take high pressure drops and continue to function. For this reason, control valve users have preferred this style of valve. Globe style valves have a narrow flow path, which changes smoothly as the valve opens and closes, controlling flow out of the valve smoothly as the valve changes positions. Precision Control Zero External Leakage High Cycle Capability Interchangeable Characterized Seats High Rangeability (Turn Down) Tight Shutoff Bubbletight Low Maintenance, Few Parts Compact Design, Light Weight High Flow Capacity Energy Efficient Efficient Shearing Action for Solids and Fibers 316 sintered metal seats are impregnated with TFE or graphite to provide positive shut-off and eliminate galling when contacting the hard coated ball. Characterized Seats with Metal A TFE impregnation or Metal G graphite impregnation in sizes 1/4" - 4". 2 How to Sell Characterized Seat Control Valves TP-10D-1

3 What problems do they have with control valves that they use? Although globe valves offer good flow characteristic and can take high pressure drops, they lack many features which other valves offer. The features are: Weight - Diaphragm actuators and globe valves are inherently heavy devices. Larger overall size means even higher weights. Shaft Seal - Linear valves have a low lifecycle and shaft packing problem, inherent to their design. When the product is exposed to the atmosphere, oxidation processes start, which will corrode the shaft surface and, over time, the shaft will show the corrosion. Regardless of the shaft surface finish and the wiping function of the packing of the valve bonnet, there will still be a small quantity of the product imbedded on the microscopic surface holes on the shaft. Packing of the valve bonnet will not hold and the valve will leak in the bonnet area. This creates higher friction force between the shaft and packing which causes valve sticking and sometimes the actuator cannot operate the valve at all. Flow Capacity - Restricted flow area of globe valves offers less flow capacity (C v ) as compared to other valve designs. This means when the line size is 3", the globe valve would most likely be 3". Shut-off - Unless the globe valve is offered with a resilient material over its seat ring, the valve does not offer good shut-off ability. The metallic valve plug over the metallic seat ring, at best, offers class IV or V shut-off. When resilient seat members are added, the valve loses its ability to take high pressure drop. Maintenance - Taking apart a globe valve which has been in service for about a year is not easy. Seat rings usually are the hardest part to remove. Most users of globe valves send them out to valve repair shops for repair. Cost - Initial purchase price is considerably higher than other valves and some that are customized can be very expensive. Accessories - More than ever, users of control valves would like to have feedback potentiometers or limit switches with the valve. However, these accessories cannot be used with such valves easily. History The double seal ball valve became a success as an on-off device when Teflon became commercially available and used as seat material in construction of such valves. In some control applications, such as pulp stock, where globe valves were not performing adequately, ball valves offered extremely successful control function. This success led to variations being developed which brought about the specially designed ball valves for true and series modulating applications. The standard round, ported, conventional resiliently seated ball valve is limited to maximum pressure drop of about 150 psi. This is because seats are exposed to the following media and their shape is deformed when much energy is killed around them. In proportional control applications, another problem with round ported valves is their flow capacity changing too much when the valve position is changed only slightly. For years, many manufacturers attempted to redesign the rotary valves to take high pressure drops with good flow characteristics. V- Ball and Camflex are two of the many that were designed with segmented balls and metallic seat rings. Although they offer high pressure drop capability and good flow characteristics, they do not offer tight shut-off, low cost, low weight and, most importantly, simple design that makes maintenance easy. These specially designed valves were made available with linear actuators that require a special, complicated mounting design. Characterized Seat Design Metal seat technology invented and patented by Worcester Controls is what is needed to make a characterized seat. Since all-metal seats are in contact with the metallic ball create galling problems, other valve manufacturers have not been able to offer the characterized seat concept. The graphite or Teflon filler in Worcester s metal seat allows full contact of the ball with the seat sealing surface without any short or long term problems. While the seat filler is lubricating the movement of the seat and ball, the super-round ball is hard coated, in which Teflon and nickel solutions are applied to the ball surface and the coating does not come off because it is embedded into the metal. The super-roundness and electroless nickel coating of the ball with self-lubricating seat offers tight shut-off (better than Class VI), long life, low torque, high pressure drop capability and, best of all, flow characteristics which can be selected to fit the particular control application needed. The characterized seat control valve gives you extremely accurate control through the entire valve stroke with seat openings designed specifically for your process. This design means efficient, straightthrough flow, rotary shaft sealing and bubbletight shutoff. The V-shape of the standard seat in characterized seat control valves is precision laser cut and offers inherent modified equal percentage flow characteristic. Slotted seat valves have inherent linear flow characteristics. If your requirements are different, we change the seat cut. Seats with multiple ports and custom openings as shown below are available to meet your unique control needs TP-10D-1 How to Sell Characterized Seat Control Valves 3

4 Recommended Product Specification for Characterized Seat Control Valves Available with special stem design to meet fugitive emission requirements. Impregnated Metal Seats Graphite or TFE impregnated in 316 S.S. or other metals. Metal seats to be full size, same as the resilient seats, in order to provide for ability to handle 800 F, pressures up to 1440 psig and pressure drops to 500 psi for liquids and 300 psi for steam. Seats to be available in various openings for specific C v and specific characteristics. Seats to be available with a slotted opening for linear control characteristics. Valves to offer rangeability in excess of two hundred to one if needed. Valves to be bidirectional. Valves to be available with a resilient upstream or downstream seat to reduce torque and provide tight shut-off. Ball to be super round and coated with hard nickel to provide for smooth control and long life. Ball and stem engagement to be free of play to eliminate hysteresis. The characterized seat to provide for shearing action in handling slurries and abrasion resistance. Valve to be equipped with compact rotary pneumatic or electric actuator. The valve should be available with inherent characteristics, linear and equal percentage or other characteristics as needed. The valve to be rotary design, compact and low weight. The valve to be available in one-piece flanged, flangeless wafer design or three-piece body with various end connections. The valve should be constructed with minimum parts and be easy to repair if necessary CV 5 Characterized seat Resilient or round metal seat The characterized seat control valve is a bidirectional valve. % Open Simple change out of the seat permits change of valve characteristic to match your process requirements. 4 How to Sell Characterized Seat Control Valves TP-10D-1

5 Characterized Seat Control Valve Features and Benefits FEATURES BENEFITS Simplicity: Valve is as simple as any ball valve. It has very few parts and is easy to assemble. Tight Shut-off: Bubbletight with A seat and better than Class VI shut-off rating with G seats. Rangeability: Rangeability of at least 80 to 1. Cost: Lower than other high pressure drop control valves. Weight: The valve, actuator and positioner combination is about 30% lighter than a globe valve assembly. Size: Compact assembly size. Shearing Action: As the ball moves across the seat opening, fibers and solids are chopped off. Low Flow Control: C v of.007 or less with slotted seats. Flexible C v : Change the seat angle or slot and get higher or lower C v. Non-Clogging Flow Path: Straight flow path allows the solids to pass through. Erosion Resistance: Hard ball and seat surface, along with the easy flow path through the valve, offer very long, repeatable performance in abrasive applications. Repeatability: Matched ball and stem engagement in the valve and use of control couplings between positioner, actuator and valve eliminates hysteresis in the valve assembly. High Pressure Drop: Liquids up to 1440 lb. of pressure per square inch and 300 lb. of steam have been established limits for the characterized seat. Made in the USA: The electrically actuated control valve is 100% US made. Package Manufactured: Complete valve, mounting kit, electric actuator and positioner are all designed and manufactured by Flowserve. Simplicity: Maintenance cost is considerably less then globe valves. The valve does not have to be sent out for repairs. Tight Shut-off: In many batch process control applications it is important that the control valve have tight shut-off so when the process is completed, the media does not leak downstream of the valve and go to waste. Rangeability: For those customers with applications that have large changes in the upstream side of the valve, more control range in a valve is a must. Characterized seated valves offer controllable flow through its 95% of travel. Cost: In times where price is important, this product is about 20% - 30% less than those products that can do the same job. Weight: Less stress on the piping system. No need for extra support. Size: Lower weight and easier maintenance. Shearing Action: Control of fibers and solids become much easier, even at minimum flow requirements. Low Flow Control: Only needle type globe valves have been used for low flow control applications. They are very expensive and do not last long. Flexible C v : If service conditions change or sizing of the valve was not done right, simply change the seat. Non-Clogging Flow Path: Restricted flow path of the globe valves is a big problem in applications involving solids. Erosion Resistance: Globe valves and abrasive applications have always been the big problem in control applications. Repeatability: No hysteresis means tight and repeatable control High Pressure Drop: All advantages of ball valves available for difficult control application. Made in the USA: If we make it, we can control it. Money stays in our own country. Package Manufactured: One manufacturer to deal with. TP-10D-1 How to Sell Characterized Seat Control Valves 5

6 High Performance Stem Seals A new stem seal design, consisting of PEEK and Polyfill thrust bearings and seals, significantly increases valve cycle life over conventional control valves and extends time between adjustments. Valve action is rotary. This means that toxic fluids, flammable fluids, and fluids that tend to crystallize or oxidize upon contact with the atmosphere are fully contained and do not inhibit the freedom of motion of the valve. Stem Seals for EPA Requirements For an extended leak-free process environment and to meet EPA requirements, Worcester offers the CPT 94 Control Valve. The Series CPT 94 valve is a NACE compatible, rugged, throttling ball control valve for fluids such as chlorine, phosgene, and many toxic liquids and gases. All Worcester standard and characterized seats are available in this valve configuration. Sizing Refer to technical paper TP-6D-1, Ball Control Valve Selection Manual for control valve sizing. Many customers know the required C v. However, if the that information is not available, the following must be obtained: Flow Rate - Liquids: gallons or lb. per minute. Steam: lb. per hour. Gas: Standard cubic feet or actual cubic feet per minute. Specify gravity. Pressures in and out of the valve. Temperature Line size Control type - Level, flow, pressure, temperature, Ph and slurry. Standard high-cycle, high performance stem seal Selection Series CPT 94 high-cycle, antifugitive emission stem seal Worcester s control ball valve can be divided into the following four (4) categories: Worcester s Control Ball Valve Round Seat Characterized Seat Metal Soft Angular Slotted In selecting and recommending control valves, one has to consider the following in order to make the best selection or recommendation: Performance needed of the control valve for application. Overkill - to much valve for the job. Price - is the package the most economical for the given application? Characterized Seat Valves are used for the following applications: Low flow control High abrasion Solids High temperature Steam control Ph control Pulp Cryogenics Heat transfer fluids 6 How to Sell Characterized Seat Control Valves TP-10D-1

7 Actuation Worcester offers a complete line of pneumatic Series 39 and electric Series 75 actuators for use with the characterized seat valve. Traditionally, spring diaphragm actuators have been used with control valves. These are linear actuators and are basically designed for rising stem valves. Diaphragm actuators are big and slow-responding. They are heavy and not as reliable as piston actuators when they are used with V-Ball or Camflex type valves. The linear motion has to be converted to rotary in the linkage between the valve and actuator. This conversion is expensive and, after a while, the unit will pick up slop in the linkage components. The slop (hysteresis) is not good for control valve assemblies. In selling the Series 39 actuator against diaphragm actuators you should remember that the Series 39 has no slop, uses simple bracketry, and is a high-cycle actuator that cycles and performs better than any other actuator in control applications. Also, it is much more responsive to signal changes. Due to the expense, complicated design and unreliability, users of control valves have pneumatic actuators. Compared to pneumatic actuators, there are few electric actuators that have performed well in control applications. Worcester s Series 75 is being used for digital (binary) and/or analog applications and its performance is very good. Using an I-75 will allow you to directly couple the actuator with a programmable controller. For analog control signals, the AF-17 is one of the best electric positioners on the market. New products like the Data Flo P and Data Flo C provide built in positioners and controllers for the 75 actuator. Valve Wafer Configuration CPT 151 & 301 Sizes Pressure Rating End Connections Cryogenic Design C 44 ¹ ₄", ¹ ₂", ³ ₄" 1000 psi max Screw End, Socket Weld, Three-Piece, Flanged C51/C52 1", ¹ ₂", 2", 3", 4" Butt Weld, ANSI, 1 (not shown) Class 150 or 300 Flanges Wafer CPT 151 3", 4" ANSI Class 150 Wafer - For use CPT 301 ANSI Class 300 between ANSI Class 150 or 2 Class 300 Flanges Flanged CPT 51 ¹ ₂", ³ ₄", 1" ANSI Class 150 ANSI Class 150 or CPT 52 1¹ ₂", 2", 3", 4" ANSI Class 300 Class 300 Raised 3 Face Flanges Three-Piece CPT 44 ¹ ₄", ¹ ₂", ³ ₄" 1000 psi max Screw End 1", ¹ ₂", 2" Socket Weld 4 Butt Weld Anti-Fugitive CPT 94 ¹ ₄", ¹ ₂", ³ ₄", 1" 1000 psi max. Screw End Emission 1¹ ₂", 2" Socket Weld 5 Three-Piece Butt Weld Anti-Fugitive CPT 94 ¹ ₂", ³ ₄", 1" ANSI Class 150 ANSI Class 150 or Emission 1¹ ₂", 2", 3", 4" ANSI Class 300 Class 300 Raised 6 Flanged Face Flanges *Characterized seat clean valves and cryogenic valves are available through Worcester s Custom Products Department. TP-10D-1 How to Sell Characterized Seat Control Valves 7

8 Competition The CPT valve with the characterized seat is unique and is concept that is offered only by Worcester Controls. The metal seat technology that Worcester has developed is the key to making the characterized seat. You can find characterized trim valves in the market which are expensive and complicated. They do not offer as good a shut-off as the characterized seat. The total characterized seat, actuator and positioner price is considerably less than the V-Ball or Camflex. This is a product that you can sell at list price. Flowserve Corporation has established industry leadership in the design and manufacture of its products. When properly selected, this Flowserve product is designed to perform its intended function safely during its useful life. However, the purchaser or user of Flowserve products should be aware that Flowserve products might be used in numerous applications under a wide variety of industrial service conditions. Although Flowserve can (and often does) provide general guidelines, it cannot provide specific data and warnings for all possible applications. The purchaser/user must therefore assume the ultimate responsibility for the proper sizing and selection, installation, operation, and maintenance of Flowserve products. The purchaser/user should read and understand the Installation Operation Maintenance (IOM) instructions included with the product, and train its employees and contractors in the safe use of Flowserve products in connection with the specific application. While the information and specifications contained in this literature are believed to be accurate, they are supplied for informative purposes only and should not be considered certified or as a guarantee of satisfactory results by reliance thereon. Nothing contained herein is to be construed as a warranty or guarantee, express or implied, regarding any matter with respect to this product. Because Flowserve is continually improving and upgrading its product design, the specifications, dimensions and information contained herein are subject to change without notice. Should any question arise concerning these provisions, the purchaser/user should contact Flowserve Corporation at any one of its worldwide operations or offices. For more information about Flowserve Corporation, contact or call USA FLOWSERVE CORPORATION FLOW CONTROL DIVISION 1978 Foreman Drive Cookeville, Tennessee USA Phone: Facsimile: Flowserve Corporation, Irving, Texas, USA. Flowserve and Worcester Controls are registered trademarks of Flowserve Corporation. TP-10D-1 05/03 Printed in USA