Valves steam pressure regulator

PRV—pressure regulating valve Steam pressure regulation Overheating of evaporator Provide safety valve on main steam line also... 

Connect the safety valve ( C) and the safety trap (D) to the steam generator. In order for the system to function properly, the bottom of the glass tube that acts as the safety valve and pressure regulator must be below the water level in the steam generator. Usually a position 1 to 2 cm from the bottom of the flask is satisfactory. 

Check the performance of steam pressure regulating valve... 

Isolation Valve (BWR) and Steam Pressure Regulator Failure (Closed)... 

Turbine trip, loss of condenser vacuum, closure of the main steam isolation valves (in BWRs) and failure of the steam pressure regulator ... 

Water-steam checks include monitoring boiler NOWL and operating steam pressure, and the periodic testing of low-water cutoff controls, pressure gauges, and the FW regulator valve. 

If very close control is desired, then any disturbance due to steam pressure changes should be minimized. Figure 7-9 shows how this can be done using a cascade control system. In this case, the temperature of the process stream is measured and compared to its desired value, as before. The output of the controller, however, instead of affecting the control valve, regulates the set point of a second controller, the steam-pressure controller. This controller compares the set point determined by the first controller with the pressure downstream of the steam valve. 

The process control scheme suggested for the steam superheater is shown in Figure 10.2. This flowscheme features a control valve on the saturated-steam inlet line. A temperature controller taking its signal from the steam outlet line ensures the flow is regulated to maintain the superheater temperature of 380°C. Steam pressure is... 

The Safety Valve was kept closed by means of a lever and a movable weight sliding the weight along the lever enabled Papin to keep the valve in place and regulate the steam pressure. 

SELECTION OF A PRESSURE-REGULATING VALVE FOR STEAM SERVICE 6.27... 

Select the size of the pilot-controlled pressure-regulating valve. Enter the capacity table in the engineering data of an acceptable pilot-controlled pressure-regulating valve, similar to Table 6.17, at the required capacity, 30,000 lb/h, and project across until the correct inlet steam pressure column, 225 psig, is intercepted, and read the required valve size as 4 in. 

Related Calculations. To simplify pressure-reducing and pressure-regulating valve selection, become familiar with two or three acceptable valve manufacturers engineering data. Use the procedures given in the engineering data or those given here to select valves for industrial, marine, utility, heating, process, laundry, kitchen, or hospital service with a saturated or superheated steam supply. 

Steam turbines with electrical generators are used to recover the power from high pressure steam when the plant steam balance requires additional low pressure steam. As such, they provide more energy-efficient pressure regulation than a simple pressure control valve. Admission or extraction of steam to a header between stages, and/or condensation of exhaust steam fulfill additional steam balance and energy recovery needs. 

The advantages of steam are the excellent heat transfer coefficient (>6000 W/(m K)), the constant temperature over the whole exchange area and the fast and convenient regulation of heating by means of a throttle valve. Lowering the steam pressure leads to lower condensation temperatures [13]. 

Steam-Heated Degreasers A steam pressure reducer or regulator, or both, is required and should be designed for the degreasing solvent used. A pressure gage and relief valve should be installed on the low-pressure side. An automatic shutoff valve should be provided in the steam line to shut off the steam in case of insuffi-... 

Step 5. Control product quality and meet safety, environmental, and operational constraints. The pressure in V-100 is controlled by adjusting the flow rate of the vapor stream using valve V-3. Pressure regulation in T-101 is carried out by adjusting V-5, the coolant valve to the condenser E-101. Since both of the products from T-101 are required to meet specifications, the LV configuration is implemented, noting that the reflux ratio in the column is less than five. Thus, the reflux valve, V-7, is adjusted to control the distillate composition, and the reboiler steam valve, V-9, is used to regulate the bottoms composition. 

The viscosity of liquid sulfur increases rapidly with temperature. It is better to maintain the temperature of liquid sulfur between 125 and 130 °C for ease in pumping. The liquid can be easily sprayed through the nozzles of the spray guns installed in the burners for proper burning. At temperatures above 145-150 °C it becomes difficult to pump and spray. Hence, the steam pressure in the jackets of liquid sulfur lines, valves, pumps, etc., should be controlled at 3.5-4.0 kg/cm by means of a pressure regulator. A safety valve should be provided on the steam supply line and set to blow off (release steam) at 4.8-5.0 kg/cm. ... 

Pressure in the steam line should not exceed 2.5-3.0 kg/cm. Pressure regulating and safety valves should be set accordingly. 

A steam-jet thermocompressor is employed when low-pressure steam is used for the evaporation and the available steam pressure is high. The Jet compressor essentially replaces the existing pressure regulator or reducing valve that controls the steam pressure (and temperature) for evaporation and can be applied easily to single-effect and multi-effect units under the right conditions. 

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