Control stations

Whenever it is necessary to control the process level, pressure, temperature, etc., a control station is installed. A control station may be as simple as a single control valve or it may contain several control vahes, block valves, bypass valves, check valves, and drain or vent valves. 

Bypass valves are sometimes installed to allow the control valve to be repaired without shutting in production. On large, important streams the bypass could be another control valve station. Manual bypass valves are 

The piping around any facility, other than the straight pipe connecting the equipment, is made up primarily of a series of control stations. Flow from one vessel goes through a control station and into a piece of pipe that goe.s to another vessel. In addition to considering the use of block valves, check valves, etc., all control stations should be designed so that the control valve can be removed and any bypass valve is located above or on a level with the main control valve. If the bypass is below the con tiol valve, it provides a dead space for water accumulation and corrosion. 

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With the electro-hydraulic system the signals, power and hydraulic supplies are sent from a Master Control Station (or MCS) on the host facility down Control Umbilicals (Fig 10.36) to individual Junction Boxes on the seabed or subsea structure. 

The master control station allows the operator to open and close all the systems remotely operated valves, including tree and manifold valves and downhole safety valve. 

The system PLC handles the sequential control of the system, while the actual manipulation of the fish block in the X-ray beam is done by joystick from the operators control station. 

In addition to energy conservation, the variable speed drives offer better control because of a faster response, ie, reduced dead band. They are also sometimes chosen for safety reasons because of elimination of the control station and accompanying valving. The capital saved by use of a smaller motor and elimination of the control valve partially compensates for the cost of the drive. 

Operator control stations. These typically consist of color graphics monitors with special keyboards, in addition to a conventional alphanumeric keyboard, containing keys to perform dedicated functions. Operators may supervise and control processes from these stations. A control station may contain a number of printers for alarm logging, report printing, or hard-copying process graphics. 

When local or central computers are used for controlling the operation of HVAC installations in buildings, they are described as building automation systems. In the control station, operators communicate with control installations, which are connected through the computer plant. Computers for individual use are called personal computers (PCs). The use of PCs for technical and economic tasks in the past few years has increased considerably. The business overflows with PCs, which get greater data power and memory at lower prices. 

Because of these solutions, important technical data can be transferred from local instrumentation (control system) through data-based controllers to a control station with computers. The operator may use the many variations that the software data system provides. Technical data operation may be digital off/on messages such as the status of operation and the performance of alarms or analog measurements such as temperature, humidity, pressure, velocity, energy usage, etc. 

From the operator s PC in the control station, the operator should be able to perform the following operations ... 

In larger facilities much of this monitoring work is carried out in real time, with the data transmitted to a remote control station. Increasingly, the corrective actions necessary may take place automatically through a computer modem. 

A control station employed to reduce high pressure steam to one or more lower pressures, thus rendering the steam suitable for a number of downstream processes. 

Post-treatment soil and earthworm samples were collected from all sites on Day 0 (application day), 1,2,3,4,6,8,12,16 and 24 on treated sites. Samples on Day 0 were collected within 3h of chemical application. Soil from control sites was sampled on Day 7 post-application only. One in-furrow soil sample from each control station was collected and the six samples were pooled. Within a given field, earthworms from each of the six stations were composited for analysis by combining all in-furrow samples into one composite and all between-furrow samples into another. Earthworms from control sites were sampled in-furrow on Day 8 and 16 post-planting only. 

STATE the purpose of the following components of a typical control station ... 

DESCRIBE the operation of a self-balancing control station. 

Control stations perform the function of a controller and provide additional controls and indicators to allow an operator to manually adjust the controller output to the final control element. 

The self-balancing M-A control station shown in Figure 34 has several controls and indicators that are basically the same as those shown on the M-A control station in Figure 32. However, there are some which differ. In addition, the controller does not require a balancing procedure prior to shifting from one mode (manual or automatic) to another. 

A self-balancing control station s non-operating mode output signal follows the operating mode output signal. 

A series of gravity cores was collected inside the inlet and at a control station located some 5 km north of the inlet in Port Orchard Passage, as shown in figure 2. The sedimentation rates as determined by 210Pb are shown in figure 4a where a least squares fit of the data gives an average sedimentation rate of... 

Figure 4a. Sedimentation rates at Stations SIN 1A (control station), SIN 2, SIN 3, and SIN 4...

Hellstrand But if you have an idea that this is an important control station, how can we take the standpoint that the experiments don t say anything They may be difficult to disentangle, though. 

As a result of the experimental studies, the simulations, and the calculations, the following safety precautions were taken. The only foreseeable process upset resulting in a temperature excursion in the nitrators is a deviation in the feed ratios. Control features and interlocks were installed to reduce this possibility. The sulfuric acid flow control station was designed in such a way that flow of this process heat sink is not halted upon complete failure of the flow controller. Low sulfuric acid flow results in automatic shutdown of the nitric acid and benzene feeds. 

SPMs such as AFM, FFM, and SSPM were performed with a SEIKO SPA-300 unit together with an SPI-3700 control station. Details for fluorescence microscopy by SNOAM based on a modified SEIKO SPA-300 unit with an SPI-3700 control station were reported previously [27-33]. Conventional fluorescence microscopy was carried out with a Nikon XF-EFD2 fluorescence microscope [40]. SIMS was performed with a Perkin Elmer PHI model 6600 SIMS system with a Ga liquid metal ion source (beam diameter ca. 80 nm). For mapping of F negative secondary ions, a width of ca. 50 pm was scanned with 256 lines. 

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