Pressure discharge control unit

Mercury vapor discharge from vents of reactors or storage tanks at normal atmospheric pressure is controlled readily by means of activated carbon. Standard units (208-L (55-gal) dmms) of activated carbon equipped with proper inlet and outlet nozzles can be attached to each vent. To minimize the load on the carbon-absorbing device, a small water-cooled condenser is placed between the vent and the absorber. 

The effects of temperature, pressure, and type of feed on NHDS were studied at adiabatic conditions in two fixed-bed units (Figure 6.2). Hydrogen was fed to the reactors by means of a high-pressure compressor and quantified by mass flow meters. High-pressure discharge pump is used to introduce the feed to the reactors. The feed flow is measured and controlled by weight on an electronic scale. The reaction... 

Fans are classified according to the discharge pressure. Reprinted per written permission from the Air Movement and Control Association International, Inc., the AMCA Standard 99-1401-66 from Standards Handbook 99-56 1986, the total static pressure classification for operating limits for central station units is as follows ... 

This type of compressor will continue to compress the air volume in the down-stream system until (1) some component in the system fails, (2) the brake horsepower exceeds the driver s capacity, or (3) a safety valve opens. Therefore, the operator s primary control input should be the compressor s discharge pressure. If the discharge pressure is below the design point, it is a clear indicator that the total down-stream demand is greater than the unit s capacity. If the discharge pressure is too high, the demand is too low and excessive unloading will be required to prevent failure. 

Here is a problem that came up on a sulfur recovery facility in Punto Fijo, Venezuela. The combustion air blower, shown in Fig. 28.8, was a fixed-speed, motor-driven centrifugal machine. The air intake filters were severely fouled. They had a pressure drop of about 8 in H/). The atmospheric vent valve, used to control the discharge pressure at a constant 12 psig, was 50 percent open. The unit engineer had been asked to calculate the incentive in electrical power savings that would result from cleaning the filters. 

Fig. 12. Schematic diagram of the experimental set-up for plastisol moulding into thin flat moulds 1 — loading of raw materials 2 — damper 3 — pump unit 4 — plunger 5 — discharge tube 6 — inlet channel (round runner) 7 — metallic bottom half mould 8 — top half mould (of lucite for low-temperature moulding and of steel for moulding into hot mould) 9 — pressure gauge 10 — stub tube for control 11 — drain cock 12 — conical flat tube instead of round point runner bolts for controlling the width of forming cavity within the limits of 0.15-1.5 mm...

Fig. 13. Automatic pipet. This automatic pipet (Analmatic Baird and Tatlock) is another application of the syringe pipet. This pipet acts by means of electrical controls as compared to the mechanical or motor-driven ones. The filling is accomplished by hydrostatic pressure and the discharge by means of the weighted pipet piston. The inlet and outlet valves are electromagnetically activated. The pipet has been employed in the dispensing unit shown in Fig. 14.

Presently the electronics controlling the pumps and valves predominantly protect the turbo pump and the PIMMS from damage. Since the high voltages driving the system could initiate detrimental arc discharges between electrodes and metal structures, they are only to be applied at low pressure. Therefore, this control of high priority is supplied by an independent unit. 

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