Liquid sampling valve

An effective catalyst recycling with no loss of catalytic activity was accomplished by removing the liquid phase via the liquid sampling valve and re-charging the autoclave with a solution containing the substrate. In all cases, no rhodium leaching occurred. Remarkably, the hydrogenation activity of the 1,3-bis-... 

Sample volume (internal in the case of liquid sample valve)... 

F, = Valve for liquid samples, = Valve for vapour samples, = Drain valve, Vf — F., = Valves for admitting air, B — Evaporator, D = Perforated copper tube, T — Thermo-wells, C = Condenser, P = Manometer, N = Safety valve... 

Figure 2 Repressure System and Liquid Sampling Valve...

Hydroformylation reactions were performed in a 90-mL Fischer-Porter bottle equipped with a gas inlet valve, liquid sampling valve, and star-head magnetic stir bar. The pressure apparatus was immersed in a constant-temperature bath maintained at 33.6 0.5 °C in a well-ventilated fume hood. A magnetic stirrer placed below the bath provided efficient stirring. 

The cell and. the liquid-sampling valve were immersed in a bath of 2-methyl pentane which was cooled by a liquid nitrogen cold finger. The bath was contained in a transparent Pyrex dewar cylinder and agitated with an electric stirrer. The temperatures of the bath and die equilibrium liquid were continuously recorded on a multipoint recorder by use of copper-constantan thermocouples. The cell temperature was maintained at a constant value by manually controlling the flow rate of liquid nitrogen. The lowest temperature attainable in the 2-methyl pentane bath was about -250 F where the viscosity of the liquid increased to such a point that stirring became difficult. 

Perkin- F.lmer 8410 Yes Yes Single detector instrument (detector chosen on purchase) FID BCD FTD FPD TCD 1. Plash vaporisation 2. Split-splitless injector 3. Manual or automatic as sampling valves 4. Manual or automatic liquid sampling valves No No No No No Yes/Yes Yes, down to -80 C... 

Perkin- Flmer 8700 Yes Yes BID BCD BPD TCD Hall B.C. photoionisation dual detector instrument (Detectors chosen from above list) 1. Plash vaporisation 2. Split-splitless 3. Programmable temperature vaporiser 4. Gas sampling valve 5. Liquid sampling valve Yes Yes Yes Yes - Yes/Yes Yes... 

A4 Shut-ofTValvt vs Vapoi Snntjklijig LS Liquid Sampling Valve PG Pressure Generator GC Gas Chromatograph — Liquid Loop Loop... 

On propene concentrates, the sample may be introduced as a liquid by means of a liquid sample valve or by vaporization of the liquid as above. On propene concentrates having a propene content of less than 80 %, only the alternative technique of trapping a sample of liquid and vaporizing the entire sample into an evacuated container shall be used. 

Liquid Sampling Vahe— Any liquid sampling valve may be vised that will permit the rqnodudble introduction of the butadiene concentrate as a liquid vmder its vapor pressure or higher and in a quantity sufficient to meet the sensitivity and resolution requirements in 5.1 and 5.3, respectively. ... 

Sample Inlet System, Liquid—A. liquid sampling valve shall be provided, capable of entrapping a fixed volume of sample at a pressure at least 200 psi (1379 kPa) above the vapor pressure of the sample at valve temperature, and introducing this fixed volume into the carrier gas stream ahead of the analyzing column. The fixed sample volume should not exceed 1.0 pL and should be reproducible such that successive runs agree within 2 % on each component peak area. The liquid sampling valve is mounted exterior of any type heated compartment and thus can operate at latoratory ambient conditions. 

Sample Inlet System, Gas (Instrument Linearity)— Provision is to be made to introduce a gas phase sample into the carrier gas stream ahead of the chromatographic column so that linearity of the instrument can be estimated from response curves. The fixed volume loop in the gas sample valve shall be sized to deliver a total molar volume approximately equal to that delivered by the liquid sample valve in accor nce with 5.1.2. (See Section 6 for further explanation of instrument linearity check procedures.)... 

Sample Filter—An optional device to protect the liquid sampling valve from scoring due to the presence of foreign contaminates such as metal shavings, dirt, etc., in a natural gas liquid (NGL) sample. The filter can be of a small total volume, or an in-line type design and contain a replaceable/disposable element. 

Floating Piston Cylinder—A strongly preferred and recommended device suitable for securing, containing, and transferring samples into a liquid sample valve and which preserves the integrity of the sample. (See Fig. 3.)... 

Apparatus Preparation—With the proper column(s) and liquid sample valve in place, adjust operating conditions to optimize the resultant chromatogram. Using the reference standard, introduce the sample in the following manner. 

Operate the liquid sample valve either manually or automatically to iqject the liquid sample into the carrier gas flow immediately ahead of the chromatographic column. Actuate the sample valve quickly and smoothly to place the sample on the column all at once and to ensure continuous carrier gas flow through the column. 

Connect the sample outlet Valve B on Cylinder B to the inlet of the chromatograph liquid sample valve. All connections and tubing are to be made of material impervious to the sample composition and of as small diameter and shortest length of plumbing as is practical, thereby minimizing dead space. All tubing between sample cylinder and liquid valve should be the same diameter. 

Sample Introduction—Sample introduction may be either by means of a constant-volume liquid sample valve or by injection with a microsyringe through a septum. If the sample is injected manually, cool the syringe to 0 to 4 C (32 to 40 F) before taking the sample from the sample vial. 

Sample Fo/ve—Either a constant-volume gas sampling valve or a liquid sampling valve may be used. If a gas sampling valve is used, greater care must be taken to ensure that the vaporized butylenes that are injected into the chromatograph are a true representation of the sample. 

If the liquid sample valve is used, the sample cylinder must be pressured up to at least 1100 kPa (160 pag) with an inert gas, sudi as nitrogen or helium (Warning—See Note 1) Also a valve must be installed in the purge line downstream of the liquid sample valve to ensure the butylenes sample in the sampling valve is entirely in the liquid phase prior to injection into the column (Warning— see Note 2). 

If a liquid sampling valve is used, pressure the sample cylinder to at least 1100 kPa (160 psig) with either helium or nitrogen. 

Microlitre syringes, automatic syringe injectors, and liquid sampling valves have been used successfully for introducing representative samples into the gas chromatographic inlet. 

Sample Introduction System—Any system capable of introducing a representative 0.1 to 1.0-pL liquid sample into the split inlet device of the gas chromatograph. Microlitre syringes, autosamplers, and liquid sampling valves have been used successfully. The split injector should be capable of accurate split control in the range from 10 1 to 500 1. 

Sample Inlet System—The sample inlet sy em must have variable temperature control capable of operating continuously at a temperature up to the maximum column temperature employed. The sample inlet system must allow a constant volume of liquid sample to be injected by means of a syringe or liquid sampling valve. 

---