Valve back pressure regulating

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. 

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.

Figure 9.5 Back pressure regulation valve assembly all functions -two temperature regulators (CVT) and solenoid (EVM) (Courtesy of Danfoss)...

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. 

A service gauge is usually fitted adjacent to the valve or as part of the valve assembly, to facilitate setting or readjustment. Above about 40 mm pipe size, the basic back pressure regulation valve is used as a pilot to operate a main servo valve. Other pilot signals can be used on the same servo. 

Figure 10.2 Use of back pressure regulating valve to maintain evaporator pressure (and temperature)...

Figure 5.28 Schematic of the experimental set-up. Water/ethylene glycol/SDS reservoir (a) high-pressure liquid pumps (b) catalyst/ substrate HPLC injection valve with 200 pi sample loop (c) hydrogen supply, equipped with mass flow controller (d) micro mixer (e) heating jacket (f) tubular glass or quartz reactor (g) back-pressure regulator (h) [64],...

EV = extraction vessel HE = water bath TV = two-way through valve TC = thermocouple BPR = back pressure regulator ... 

Figure 8. Schematic representation of our technique for recovering solid products from reactions in supercritical fluids (a) shows the supercritical reactor connected to a computer controlled syringe pump (Lee Scientific Model 501) filled with scC02. (b) shows how the scC02 is used to drive the supercritical reaction mixture (colored) through an expansion valve (Jasco 880/81 Back-pressure Regulator) where the products dissolved in the fluid are precipitated.

H Pressure Sensor I Bores for Heating Wire J Air Cylinder K Air Cylinder Piston L Back Pressure Regulator M Compressed Air Cylinder P Pressure Gauge R Regulator Unit VB Bleed Valve VN Needle Valve VP Purging Valve... 

Additional equipment includes the manifold pressure regulator (MPR), Matheson Model no. 3-580 the inlet pressure regulator (IPR), Matheson Model no. 3075-1/4 the back-pressure regulator (BPR), Grove Valve Co s model no. 155 per Figure no. 11410-F-P2-A and the Corblin A1C-250 metal-diaphragm compressor, serial no. 1430. 

Fisher, Puerto Rico) with a flow rate range of 0-40 mL/min, a pressure gage (Cole-Parmer, Vernon Hills, IL) with a pressure range of 0-1500 psi, and a back-pressure regulator (Maine Valve and Fitting, Bangor, ME) were used to control water pressure and flowthrough the system. 

Figure 1. Supercritical flow reactor. Key (I) Mettler balance (2) flask with 1 0 (filtered and deaerated) (3) HPLC pump (4) bypass (three-way) valve (5) feed cylinder (6) weather balloon with feed solution (7) probe thermocouple (type K) (8) ceramic annulus (9) Hastelloy C-276 tube (10) entrance cooling jacket (11) entrance heater (12) furnace coils (13) quartz gold-plated IR mirror (14) window (no coils) (15) guard heater (16) outlet cooling jacket (17) ten-port dualloop sampling value (18) product accumulator (19) air compressor (20) back-pressure regulator and (21) outflow measuring assembly.

The pressure was controlled by 3 back-pressure regulators. BPR.l was set at 19.4 MPa, and BPR.2 and 3 were set at 8.8 MPa. For the rinse step to remove solute in the void region, SA valve remained open, where the pressure of whole system kept at 8.8 MPa, and the effluent from both column was collected in SE1. For the blowdown step, the pressure of one column kept at 19.4 MPa for the desorption step was quickly reduced to 8.8 MPa for next adsorption step by opening SB valve. 

To determine the phase boundary pressure was lowered, until phase separation occurred, which could be observed visually by a camera system D. At first the pressure lowering was done by means of a hand-valve. To keep the pressure rates more constant the process was than automated using a computer controlled back pressure regulator E (Tescom ER2000). 

C14W) that has an internal loop volume of 60 nL. The mobile phase then enters the colunm at the end of which is a UV detector (Jasco UV-1S70). The pressure in the system is determined by a back pressure regulator (Jasco BP1S80-81) which is located downstream of the UV detector. The column and the injection valve are housed in a temperature controlled water bath. Upstream and downstream pressures are measured using pressure transducers (Trafag 8891). 

The experiments are performed by setting the back pressure regulator at the desired level and progranuning die syringe pump to operate at a given flow rate. The system is then allowed to reach a steady state. Once the pressure profile in the system is established, a mixture of phenanthrene in toluene (2% w/w) is injected into the column through the injection valve and the data acquisition is started simultaneously. For each setting, the experiment is repeated more than three times to ensure reproducibility. 

Figure 1 is a schematic of one of the two supercritical flow reactors used in this work. The system is first brought up to the operating pressure by an air compressor. An HPLC pump forces the reactant solution through the reactor, the ten-port valve and dual-loop sampling system, and into the product accumulator, where the flow of products displaces air through a back-pressure regulator. The reactant inflow is rapidly heated to reaction temperature by an electric entry heater/water jacket combination, and maintained at isothermal conditions by a Transtemp Infrared furnace and an exit electric heater/water jacket combination. 

The fluid mixture coming out of the extractor is depressurized to atmospheric pressure by passing it through a heated metering valve and a back pressure regulator. The instantaneous flow rate of the gas leaving the extractor is measured using a rotameter and the total amount of gas flow is measured with a calibrated wet-test meter. 

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