diagnose valve DIAGNOSE VALVE PROBLEMS

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2 diagnose valve problems DIAGNOSE VALVE PROBLEMS remotely REMOTELY ValveWatch is a condition monitoring system for critical valves that delivers proven results. ValveWatch utilizes advanced technology to remotely monitor valves and actuators, detecting problems before they impact production. HOW IT WORKS The ValveWatch system incorporates sensors attached on or near the valve and actuator assembly to routinely monitor and record their performance. Strain sensors and actuator pressure sensors monitor valve & actuator performance during operation, while dynamic pressure sensors and acoustic sensors monitor the valve for internal seat leaks. Together, these sensors provide operators an automated checkup on the condition of the valve and actuator package. The strain sensor and actuator pressure sensor provide valuable diagnostic data each time the valve strokes. The strain sensor is permanently bonded to the valve yoke adapter and records the force applied to the valve by the actuator during a valve stroke. Problems with valve operation, including damage to certain components, are readily detected using data taken from this sensor. An actuator pressure sensor mounted to the actuator supply line records the change in actuator pressure throughout the valve stroke. Damage to the actuator or a problem with the actuator air or hydraulic supply can be detected using this sensor. The actuator pressure sensor is also used to determine when the valve changes position, causing ValveWatch to initiate a valve stroke test. For valves without a sealed cavity an ultrasonic sensor is installed downstream of the valve. The valve must be stroked closed, and a slight differential pressure is applied across the valve seat to detect a leak. If the valve seats are leaking, highfrequency noise generated by the gas or liquid media passing through the seat will be detected by this sensor. Data is collected from the sensors by the Local Data Acquisition Unit (LDAU) Assembly which consists of an IP66 weather proof box containing several modules installed as close as possible to the valve. The standard system includes two Strain/AC modules and a Communications Module. The strain channel monitors signals from the strain and static pressure sensors, and the AC channels handle the dynamic pressure sensors. The signals are conditioned and converted to digital in the sensor modules and passed to the Communications Module for wireless or data-over-power transmission to a HUB Assembly. The LDAU Assembly and the sensors are intrinsically safe and are certified according to North American and European standards for installation in Zone 0 areas. An additional communications and Ethernet module are housed in the HUB Assembly along with all the power supply, terminal strips, and intrinsically safe barriers. The HUB assembly is rack mounted in a safe area (Zone 2) or equipment room. Each Hub assembly can be configured to monitor up to eight valves. An Ethernet cable connects the HUB to a server where the data is stored, transmitted, and then analyzed for leakage. All the test results and data are stored in a secure Oracle database application. For ball valve and slab gate valve designs with sealed cavities, dynamic pressure sensors are used to test the valves for leaking valve seats. Unlike other methods of leak detection that require valves to be closed for testing, ValveWatch allows operators to monitor and identify leakage while valves are open and production is flowing. This innovative technology gives operators the ability to trend valve seal performance and proactively plan for maintenance or repair. Two dynamic pressure sensors are used: one installed in the valve cavity and one installed upstream or downstream of the valve. During a typical leak test 60,000 readings are taken from each of these sensors. They record the fluid oscillation in the sealed valve cavity, and compare the frequency and amplitude to the oscillations to those measured in the upstream or downstream flow. As the signals become similar in shape and amplitude operators are immediately warned of a potential seat leak. ValveWatch collects data from the dynamic pressure sensors on a scheduled interval or when the valve strokes, while data from the other sensors is recorded only when the valve strokes. For leak tests using dynamic pressure sensors, the system software performs the leakage calculations using patented algorithms that run automatically. The test results are compared to pre-established limits, and alarms warn operators of degrading seal conditions. For valve stroke tests, data taken from each sensor is compiled into a signature and compared against a baseline signature taken under normal conditions. Irregularities in valve signatures are identified and analyzed to determine the source of the valve or actuator problem. A simple web interface allows easy access to the system status from any location. Security is provided so that only authorized persons can access the system map, alarm window and system tree to view platform, valve and sensor status. The software provides reports and trending plots so that operators can evaluate ongoing performance. 1

3 monitor valve performance from MONITOR VALVE anywhere PERFORMANCE FROM ANYWHERE in the IN THE WORLD world ValveWatch offers clients the flexibility to monitor valves from anywhere in the world. Engineers and Technicians in remote locations can retrieve monitoring data, analyze test results, and recommend corrective action without visiting the facility. Because each client has different requirements, ValveWatch will design and implement a monitoring plan customized to fit each client s requirements. MONITORING CENTER ValveWatch staffs Monitoring Centers in Bergen, Norway, that are capable of remotely monitoring ValveWatch installations around the world. Engineers are on-line at our Monitoring Centers to analyze your data and provide up-tothe-minute graphic interpretation that is easy to understand and apply. Engineers are on-call 24/7. WEB PORTAL From a secure web portal, a single map depicts each facility with a ValveWatch custom field. Clients can select a location and a custom facility graphic shows the location and status of each valve monitored by the system. Individual test results and trends can be reviewed using an intuitive graphic user interface. ONLINE MONTHLY REPORTING A monthly report is sent to each facility summarizing the performance of the monitored valves and actuators. Valvewatch Engineers review client data, provide commentary on the performance of client equipment over the past month, and outline any corrective action that was taken. PROBLEMS IT FINDS ValveWatch makes valve and actuator problems easy to detect and simple to diagnose. Valve Problems Detected 1. Leaking Seals 2. Bent Stem 3. Valve Seizure 4. Over-tightened Packing 5. Excessive Breakout Torque 6. Valve Galling 7. Ejected Cavity Sealant Actuator Problems Detected 1. Internal Corrosion 2. Broken Return Spring 3. Cylinder Damage 4. Undersized Actuator 5. Restricted Solenoid Exhaust 6. Fluctuating Supply Pressure 7. Insufficient Air Supply APPLICATIONS 3

4 ValveWatch Monitors Performance 24/7 Blocked Solenoid Exhaust Partially blocked exhaust ports can significantly increase valve closing time. With ValveWatch, measurements taken from the actuator pressure sensor during a valve stroke can identify this problem. This example shows a signature from a valve with a blocked exhaust port compared to several signatures from a normal valve. The blocked exhaust caused an increase in stroke time of 500% for this valve. Left undetected, this problem can compromise the performance of critical systems such as ESD systems. Bent Valve Stem Bent valve stems can significantly accelerate packing wear. With ValveWatch, data taken from the strain gauge during a valve stroke can identify when this problem is occurring. This example shows a signature taken from a gate valve with a bent stem. As the valve strokes open, the bend in the stem causes a rapid increase in the thrust required to partially open the valve, followed by a rapid decrease to normal thrust required to complete the stroke. This hump in the thrust signature is an indication of a bent valve stem, and left undetected may result in external valve leaks. Excessive Breakout Torque Excessive breakout torque can eventually result in valves seizing. This example shows strain gauge signatures taken over four strokes of an offshore shutdown valve. The first three signatures display the significant increase in torque required to open the valve. The excessive torque is also apparent in the running load throughout the full stroke. The final signature was taken after the operator serviced the valve to bring it within normal specification. Left undetected, this valve could have seized without warning and compromised the safety of the facility and its workers. 4

5 Actuator Pressure Leak Air leaking from the actuator may prevent the actuator from overcoming its spring pressure. The result is a valve that does not open completely. This example shows signatures taken from two valves using the actuator pressure sensor. The top signature depicts a normally opening valve, while the lower signature depicts a valve that fails to stroke fully open when the actuator is charged. Without monitoring, actuators may leak air for extended periods before this problem is identified. Excessive Friction Excessive friction can be the result of several damaging issues inside the valve, including internal corrosion, deposit formation, or over-tightened packing. This example shows strain gauge signatures taken from two valves during a full open stroke. The bottom signature shows a normally operating valve with a smooth strain signal throughout the valve stroke. The top signature shows a jerking motion as the valve moves fully open. Often invisible from outside the valve, the rapid peaks and valleys in the strain signal are the first signs of excessive friction and a potentially damaging valve problem. 30-Day Leak Trend Without ValveWatch, leaking valve seats cannot be detected without closing the valve and conducting a manual leak test. In this example, a seat leak was identified in an offshore shutdown valve by ValveWatch while the valve was fully open and production was occurring. Readings from the dynamic pressure sensors exceeded limits and alerted personnel to the problem. Operators confirmed a small leak of 100ml within 30 minutes and repaired the valve before the leak developed further. Without ValveWatch, this seat leak would have gone undected and may have developed further until identified during the next manual test period. 5

6 engineered to eliminate complex ENGINEERED TO ELIMINATE system COMPLEX SYSTEM integration INTEGRATION ValveWatch is designed as a fully independent remote monitoring system, proven in the harshest environments. Operators prefer its stand-alone design which eliminates complex integration into existing platform systems. As an option, an OPC 1 interface to a client s DCS 2 can be provided. Once installed, the system can be expanded to include additional valves. MAJOR COMPONENTS A typical ValveWatch system for up to eight valves consists of: Strain Gauge Surface mounted to the yoke adapter between valve and actuator. Monitors thrust or torque applied during valve movement. Useful for detecting valve & actuator mechanical problems. Full bridge; 5000 ohm; full scale output 1 mv/v nominal; epoxy bonded attachment. 2 - Actuator Pressure Sensor Installed on actuator supply line after solenoid. Monitors pressure inside the actuator. Useful for detecting valve & actuator problems and supply pressure problems. Full bridge 2000 ohm; 10mV/V FS sensitivity; pressure rating 30 10,000 psi for air or hydraulic actuators. NPT female threaded connection. 3 - Dynamic Pressure Sensor Installed into a port downstream of the valve. Monitors valve for seal leaks. For some valves, an additional sensor installed into a port for the valve cavity, monitors for seal leaks with the valve open. Dynamic measurement range +/- 20 psi. at 48 mv/psi.; sampling frequency Hz.; NP T male threaded connec- tion; 8,000 psi rated stainless steel construction. intrinsically safe. ATEX rated 4 - Local Data Acquisition Unit (LDAU) Located near each valve. Converts sensor data from analog to digital for transmission to HUB Assembly. May house three strain/ac modules to monitor up to six sensors. Power requirements: VDC; Nominal data rate kbps wired, 40 kbps RF; IP66 stainless steel enclosure. 5 - HUB Assembly and Server Located in a safe area for system control and safe power supply. Receives digital data from each LDAU and sensor package located at the valve. Transmits digital data to server. Contains intrinsic safe barriers, and power supply to safely power each LDAU & sensor package. Power requirements: Amps; RJ45 10BaseT Ethernet output; 19 rack mountable. 1 The OPC Foundation, a non-profit corporation, maintains a set of standard OLE/COM interface protocols intended to foster greater interoperability between automation/control applications. 2 Distributed Control System 6

7 SYSTEM ARCHITECTURE Strain and actuator pressure sensors are installed at each valve. If leakage is being monitored, two dynamic sensors or an ultrasonic sensor are/is installed for each valve. These sensors transmit valve data to the LDAU mounted near the valve over a shielded cable. Modules within the LDAU record the data and digitize it for transfer to the HUB Assembly and Server located securely in a facility s equipment room. Data is transferred via the client s network or a ValveWatch specific network from the server at the facility to the server in the Monitoring Center. Once the data is stored on the Oracle web server, autho rized users can access the data from anywhere on the client s network. WIRED OR WIRELESS ValveWatch can transmit data between each LDAU and HUB assembly over a traditional cable connection or by using wireless data transmission. The wireless option is ideal when cable installation problems are a factor. MODULAR DESIGN ValveWatch offers the flexibility of a modular design. Valves can be instrumented with one or more sensors depending on their design and monitoring requirements. Once installed, a ValveWatch system can be expanded with minimal hardware additions. INTRINSICALLY SAFE AND APPROVED FOR HARSH ENVIRONMENTS Information regarding certifications and certificates to be found at:

8 For more information, visit us at Main office, Norway MRC Solberg & Andersen Langarinden 16, 5132 Nyborg Tlf: