Compression fittings

Standard commercial iastmmentation and control devices are used ia fluorine systems. Pressure is measured usiag Bourdon-type gauges or pressure transducers. Stainless steel or Monel constmction is recommended for parts ia contact with fluoriae. Standard thermocouples are used for all fluorine temperature-measuriag equipment, such as the stainless-steel shielded type, iaserted through a threaded compression fitting welded iato the line. For high temperature service, nickel-shielded thermocouples should be used. 

Failure of a 3/8-in compression fitting on a 1000-2500-psi ethylene line in a pipe trench resulted in a spill of 200-500 lb of ethylene. A cloud was formed and ignited, giving an explosion equivalent to 0.12-0.30 ton of TNT. This accident took place in a courtyard, giving a partially confined vapor cloud explosion. Two people were killed and 17 were injured property loss was 6.5 million. 

ISO 14236 2000 Plastics pipes and fittings - Mechanical-joint compression fittings for use with polyethylene pressure pipes in water supply systems ISO 14616 1997 Plastics - Heatshrinkable films of polyethylene, ethylene copolymers and their mixtures - Determination of shrinkage stress and contraction stress ISO 14632 1998 Extruded sheets of polyethylene (PE-HD) - Requirements and test methods... 

Similarly, from the case i = 2 of (11.106a), we obtain analogous stability constraints on the isothermal compressibility fiT ... 

Few elastomers are relied on in LNG fuel systems because of the cryogenic temperatures. Welded fittings, compression fittings, and flanged joints are commonly used with little need for elastomers for sealing purposes. For the places where elastomers must be used, teflon is the preferred choice since it retains... 

Since the real work in an HPLC system occurs in the column, it has been called the heart of the system. The typical column is a heavy-walled stainless steel tube (25-cm long with a 3-5 mm i.d.) equipped with large column compression fittings at either end (Fig. 1.1). 

Figure 3.1 Compression fittings, (a) Male fitting (b) female fitting (c) zero dead volume union.

The tubing is connected to the pump s outlet check valve by a compression fitting. The fitting is made up of two parts a screw with a hex head and a conical shaped ferrule (Fig. 3.1a). The top of the outlet valve housing has been drilled and threaded to accept the fitting. 

There is a second basic type of compression fitting (Fig. 3.1b), the female fitting, which you will see on occasion. Some column ends have a protruding, threaded connector and will require this type of fitting. This fitting is made... 

First we will need to hook up the pump inlet line. This usually consists of a length of large-diameter Teflon tubing with a combination sinker/filter pushed into one end and a compression fitting that will screw into the inlet fitting at the bottom of the pump head on the other end. Drop the sinker into the solvent reservoir and screw the other end into the inlet check valve housing. 

The next step is to use compression fittings to hook the pump outlet to the flush valve with a length of 0.02-in i.d. tubing. The flush valve is a small needle valve used to prime the pump that allows us to divert solvent away from the column when rapidly flushing the pump to atmospheric pressure. Open the valve and the line is vented to the atmosphere. This removes the back-pressure from the column, a major obstacle when trying to push solvent into a plumbed system. 

As soon as the pump begins to pump solvent by itself tighten down the outlet compression fitting and drop the flow rate to about 1 mL/min.The pump is ready to run and should be allowed to pump into a beaker for a few minutes to wash out any machining oils, if new, or soluble residues or dissolved buffer if old. 

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