Ratermann Manufacturing, Inc. Customer Service 1-800-264-7793 y Email [email protected] y Order Online at Web Store www.rmiorder.com 20A-3 TUBE TRAILER HOSE SELECTION GUIDE Dynamic Stress and Velocity Pressure flow characteristics are important factors when using an all metal hose. Dynamic stress is an important consideration when select- ing an all metal hose. The hose must not be bent on more than one plane at a time or restricted (over-bent) in any way. All metal Corrugated hoses are not designed to handle high velocity flow rates. Confirm the velocity rate of each application, and make certain that the flow rate is below the recommended threshold for a given size hose. If the velocity exceeds this threshold, it will establish a resonant frequency that will prematurely crack the hose. Selecting the Best Hose In the specialty gases industry, there are several choices when considering a hose. Here are some of the basic factors that one should take into consideration. Pressure – Make certain that the average working pressure of the hose is well above the required maximum pressure of the application. Molecular Weight – Hydrogen and helium have the smallest molecular weight, and therefore present a higher risk of permeation loss. Permeation – If permeation is a concern, consider using an all metal hose. Make certain that the flow rate is below the suggested threshold level. Other options would be an ETFE or PTFE post sintered type hose. These hoses will reduce effusion by approximately 75 percent. Purity – Hoses that effuse gases can also diffuse gases. Diffusion can introduce contaminants that could effect the high purity gas stream. If this is a concern, consider using an all metal hose. Static State – If a gas is used in a static state, there will be times when the gas is not being used (off hours, weekend). In this case, gases trapped inside the hose could effuse out. The amount lost is minimal, but over time this loss can add up. Fill Manifolds – Hoses used on fill manifolds are typically cycled (attached and disconnected from the cylinder) several times a day. The hose is exposed to continual flexing, and then disconnected (hanging open to the air). As a result, permeation of a fill manifold is of minimal concern. PTFE hoses work well in this application. Laser Cutting Systems – Using the wrong hose to supply a laser can be detrimental to the operating efficiency of the laser, depending on permeability of the hose, a high permeation hose will contribute contamination, resulting in increased downtime. Ultimately this will effect the quality of cut. When the velocity flow rate exceeds the recommended threshold, consider using a PTFE lined hose. Tube trailer transfer is one applica- tion that often exceeds the recommended threshold rate. Braiding – The stainless steel braid encases the inner core and gives the hose its strength to hold pressure. A high pressure hose can have from one (3,000 psig) to four braids (5,000 psig) depend- ing on pressure requirements. Armor Casing – Armor casing can easily be installed over the braided hose. It will prevent hose kinking and whipping in the event of a hose burst, and also protects the exterior of the hose. Fittings – Swivel fittings, hand tights, 90 degree elbows and brass heat sinks for adiabatic compression are a few of the more popular fittings in use. Medical Gases – It is very important that you select the correct hose for medical applications. One should consult an expert prior to installing pigtails. Care should be taken with Oxygen pigtails to the heat associated with “adiabatic compression.” We highly recommend the use of an extended brass volume piece on oxygen manifold pigtails. Oxygen charging manifolds should include flexible hoses with“heat sinks” installed near CGA connection. The heat sinks will help to absorb the potential heat from adiabatic compression. We highly rec - ommend the use of heat sinks. TSC Hose Breakaway For Hose Maintenance information, see pages 20A 26-27 Tube Trailer Hose Selection Guide Ratermann Hose Style TT TTS TTM Working Pressure (MAWP) 4000 PSIG 3700 PSIG 2500 PSIG Core or Liner PTFE 316 SS Monel Gas Air 4 3 4 Argon 4 3 4 Carbon Dioxide 4 5 2 Helium 3 5 4 Hydrogen 3 5 4 Natural Gas 4 3 3 Nitrogen 4 3 4 Nitrous Oxide 3 3 3 Oxygen 3 3 5 Compatibility Excellent 5 Very Good 4 Good 3 Acceptable 2 Not Acceptable N Ratermann Manufacturing, Inc. carries a tremendous range of hoses suited for all your CRYOGENIC needs. Transfer Hose for Nitrogen, Argon and Oxygen
