Pressure regulation / control

Pressure regulator - Controls the system pressure to the manifold. 

The pressure regulator controls the pressure and, indirectly, the quantity of spray material dehvered by the nozzles. It protects pump seals, hoses, and other sprayer parts from damage due to excessive pressure. 

Figure 3. Device for measuring tack-free time (1) probe (absorbent cotton) (2) timer controlling interval between exposure and activation of probe (3) oscillating stage (4) exposure timer (5) constant temperature bath and circulator (6) air pressure regulator controlling pressure on probe (7) General Electric UA-3 mercury arc, reflector, and shutter (inside enclosure)...

Exit gas leaves the top of the reactor and passes through a heated line (to avoid condensation of liquids) to a cooler-condenser. Liquid products are collected in a knockout pot and are drained through a solenoid valve actuated by a sonic liquid-level controller. A dome-loaded, back-pressure regulator controls the reactor pressure and reduces the pressure of the exit gas. The exit gas rate is measured by a wet-test meter. Carbon monoxide and carbon dioxide concentrations in the feed and exit gases are measured by two continuous infrared analyzers and are recorded. Aliquot samples of feed and exit gases are taken during each test period for analysis of all components by mass spectrometer (Consolidated Engineering Model 21-103). 

A9.2.7 Pneumatic Driving System. The.incoming air from compressor is cleaned, filtered, and dehumidified before il accumulator tank. A relief valve controls the maximum pressiirei in the tank. A pressure regulator controls. the pressiire of the air prior to its entry into the pneumatic shuttle system through the solenoid-operated valves that govern... 

LOX tests were conducted inside Cell 7 and not performed remotely like the LH2 tests. All critical hardware was controlled via a computer located within the cell. Modifications to the cell were made to flow GOX. A pressure regulator controlled incoming pressure of the gas and flow rate was controlled by a set of flow control valves located directly upstream of the CFM test tank. 

Fig. 8. Fluid-bed MTG demonstration plant schematic diagram. BPR = Back pressure regulator TC = temperature controller.

In most utibty boilers, steam pressure regulation is achieved by the throttling of turbine control values where steam generated by the boiler is admitted into the steam turbine. Some modem steam generators have been designed to operate at pressures above the critical point where the phase change between Hquid and vapor does not occur. 

When a pulsation frequency coincides with a mechanical or acoustic resonance, severe vibration can result. A common cause for pulsation is the presence of flow control valves or pressure regulators. These often operate with high pressure drops (i.e., high flow velocities), which can result in the generation of severe pulsation. Flashing and cavitation can also contribute. 

Install a pressure regulator to control source pressure... 

The synthesis gas cylinder should be installed with an instrument-quality forward pressure regulator, since this will control the experimental pressure of the whole unit. The nitrogen cylinder can have an ordinary regulator, because it is used only for flushing the unit. 

With all leaks stopped, and the reactor under test pressure with nitrogen, set the nitrogen pressure regulator to the lowest pressure on the controller, but above 0.3 atmosphere or 5 psig. Now open the flow controller and set the N2 flow to 66 mL/s, equivalent to 10.5 mols/hr rate, to start the flow. Also start heating the unit. 

The Back Pressure Regulator (BPR) shown at the end can be a gas dome-loaded Grove Inc. regulator or a spring-loaded Tescom model. The same holds for the forward pressure regulators. Instead of regulators, controllers can be used too, especially since small electronic control valves are now available. 

The unit shown on the next page in figure 4.4.1 is a somewhat simplified version of a tested, actual unit. The six gaseous feed components enter through check valves at a pressure regulated to about 4 atm higher pressure then experimental pressure, e.g., 22 atm. Six mass flow controllers set the flows and all but the nitrogen lines are secured with power to open solenoid valves (SV). 

Figure 14.10 Schematic diagram of the aromatics analyser system BP, back-pressure regulator CF, flow controller CP, pressure controller Inj, splitless injector with septum purge V, tliree-way valve column I, polar capillary column column 2, non-polar capillary column R, restrictor FID I, and FID2, flame-ionization detectors.

Most compressed air equipment operates at about 6 bar (gauge) and it is usual for the compressor to deliver air into the mains at 7 bar (gauge) in order to allow for transmission losses (see Tables 35.1-35.4). If some of the air is to be used at a lower pressure (for example, for instmment control) the pressure is reduced by means of a pressure regulator to the required line pressure. 

Back pressure regulation valves (Figure 9.5) can be used in the suction line, and their function is to prevent the evaporator pressure falling below a predetermined or controlled value, although the compressor suction pressure may be lower. 

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