Bypass system

Another pressure control method is a hot gas bypass. The author has seen a retrofitted hot gas bypass system solve an unsatisfactory pressure control scheme. In the faulty system, a pressure control valve was placed between the overhead condenser and the lower reflux drum. This produced en atic reflux drum pressures. A pressure safety valve (psv) vented the reflux drum to the flare to protect against over-pressure. A psv saver control valve, set slightly below the psv relieving... 

Van Blarcom, Peter P., Yarway Corp., Bypass Systems for Centrifugal Pumps, Chemical Engineering, Feb. 4,1974. 

Vent the Ni to atmosphere for a few seconds, if using a bypass system, to remove pressure build-up in the line prior to each run. 

Fill bypass systems, which are capable of diverting the entire hot water flow directly into the tower basin, comprise the first. 

Never inject biocides into a flow assembly (this is unfortunately very common), as plugging of the flow assembly can easily result. Also, never draw bleed (blowdown) water from the flow assembly or from small-diameter pipework forming part of the bypass system. 

Photorespiration could be overcome if Rubisco could receive CO2 more efficiently than by diffusion through the leaves. Various C4 plants, including grasses such as maize (com) and bamboo, have evolved a bypass system for the delivery of CO2 to Rubisco. 

There are several general heuristic guidelines for heat exchanger bypass systems. However, this very much remains an open research area since these guidelines are not always adequate to deal with all of... 

E-(eductor) is a slipstream or bypass system which uses a gas driven aspirator to withdraw a portion of the flow stream isokinetically, pass it through the optical system and re-inject it back into the flow stream. The system is intended for high temperature/concentration applications and multiple flow streams. 

Figure 9 Schematic of diesel-fueled burner regeneration system, (a) In-line burner, (b) burner with bypass system. (Courtesy of the Society of Automotive Engineers.)...

Since the bypass system has demonstrated good feasibility, the complex burner with its electronic controls may be replaced by a simple resistance heater powered by the alternator on the vehicle see Fig. 12. A small air pump (3-5 CFM) is used to transfer heat from the heater to the filter and provide sufficient oxygen for soot oxidation. Typical heaters arc fabricated from two nichrome resistance elements contained in MgO powder insulation with a 0.260-in.-diameter stainless steel sheath. The energy requirement for regeneration is typically 3 kW and is readily achieved from a 90-amp alternator at a speed of 6400 rpm. 

The connection of the pumping system to the manifold should be by way of a large-size trap (Fig. 3-10), which is cooled with liquid nitrogen in order to remove contaminants. In operation, the mechanical pump is started first, the pressure in the system is reduced below 100 /X, and the diffusion pump is turned on. Once a low pressure has been attained, the pumps are not ordinarily shut off unless this becomes necessary for maintenance or repair. If the system to which the pumps are connected is to be raised to atmospheric pressure regularly, a bypass system should be supplied so that the system may be evacuated... 

SOS repair includes a bypass system that allows DNA chain growth across damaged segments at the cost of fidelity of replication. It is an error-prone process even though intact DNA strands are formed, the strands are often altered. 

Figure 2. Cut-away view of the Diffstak pump and bypass system.

Distillation.—At this stage of the process there are several interesting variations from Scotch and Irish methods of distillation. Note, on the diagrams, that by means of a bypass system the beer well may be connected to either the whiskey or spirit stills these are both termed beer columns, although they are really distinct kinds of stills. 

The parts of the packaging line between stations (open conveyer) should be covered so that the goods once passed through the automatic checks cannot, as far as is practical, be handled by operators again. This is because it has been reported that up to 70% of product mix-ups and adulteration in the whole British industry are caused with the supply company deliberately bypassing systems. 

It is valuable to provide connections on the cooling water system, that may be used for flushing to dislodge any accumulations of deposits that might occur. The opportunity to isolate heat exchangers by the inclusion of bypass systems, must be included so that off-line cleaning can be carried out without the need to shut down whole sections of the total cooling water circuit. 

The use of coupled onhne spectroscopies (ATR-FTIR/Raman) for the development and the monitoring of industrial chemical processes was demonstrated by Wiss and ZiUan [14], For the investigation of two types of reaction, respective fiber optical spectroscopic probes were installed in a commercial reaction calorimeter. The authors pointed out that such a setup is more appropriate for industrial applications than bypass systems for sampling, and can be used in a pilot plant or production plant without major modification of the available equipment. 

For safety and normal plant shutdown, waste heat boilers are equipped with systems to divert flue gases away fiom the boiler and directly to a stack. One such system comprises an abort, or dump, stack upstream of the incinerator and stack. Another system includes a bypass breeching coimection between the incinerator and stack. Modem, well-designed bypass systems are equipped with isolation dampers either in the dump stack or in the bypass breeching section. In systems without isolation dampers, either hot flue gases can bypass the boiler or ambient air can dilute gases to the boiler. Because of these factors, boiler isolation dampers may improve overall heat recovery efficiencies by at least 5%. 

Circuit driers are used in the magnox reactors (52) to keep the moisture level at about 2 ppm. After startup, the level of residual gases in the CO2 increases to an asymptotic level of about 1.5 vol-% in about 100 days, 85 to 95 % of the residual gas being carbon monoxide. Particulate matter is removed in a bypass system having cyclone filters. 

Most modern HPLC injectors use the loading coil and coil bypass system. The sample is loaded at low pressure into the coil which is temporarily isolated from the solvent flow to the column on injection, the flow is diverted through the coil washing the sample onto the top of the column. With this method solvent is continuously pumped through the column at constant flow, thus minimizing injector stop-flow problems. 

A "full-capacity" steam bypass system is also provided to enable dumping the full nominal steam flow directly to the main turbine condenser in the event of certain disturbances, in order to avoid pressure surges, and corresponding power peaks, in the reactor. 

The exhaust from the low pressure turbine cylinders flows to the main turbine condenser which has three shells, located under the exhaust hoods of the low pressure turbine cylinders. The condenser is designed to accept also the steam flow from the main steam bypass system on startup, hot standby and turbine trip. During normal power operation, the steam flow to the condenser amounts to about 60% of the total steam flow, but the condenser system is designed to accommodate the full steam flow for a limited time period the steam flow shall be reduced to 60% within 20 seconds to avoid a reactor trip due to too high condenser pressure. 

A Turbine Bypass System (TBS) is provided which passes steam directly to the main condenser under the control of the pressure regulator. The TBS has the capability to shed 40% of the turbine generator rated load without reactor trip or operation of a SRV. The TBS does not serve or support any safety-related function and has no safety design. 

The main condense is designed to cond ise and deaerate the exhaust steam from the main turbine and provide a heat sink for the Turbine Bypass System (TBS). 

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