Liquid chromatography accessories and leakage treatment methods
Accessories
Typical fittings consist of screws and ferrules – designed to connect and seal the tubes. Although simple in function, describing and using them is somewhat complicated. To accurately describe an accessory, consider the following things: the shape of the receiving hole (cone or flat hole); the size of the pipe; the thread of the screw, such as 10·32, 1/4·28, etc. Accessories can also be categorized by measurement unit or by material type.
Stainless steel fittings
Stainless steel fittings, while limited in use and in equipment, are still the most versatile of many analytical equipment because they are able to withstand high pressures and are compatible with most solvents.
Stainless steel fittings are very versatile in size and shape and often vary from manufacturer to manufacturer (see Figures 1 and 2). Therefore, in order to ensure the correct use and longevity of the accessories, it is best to use accessories designed for the specific manufacturer's aperture.
Stainless steel fittings must be held together (or permanently attached) to the pipe. We recommend the following steps to you:
First install the screws and ferrules on the pipe in sequence, then connect them to the matching holes and tighten the screws by hand while ensuring that the pipe has reached the bottom of the hole. Finally, use a wrench to rotate the 3/4 buckle. Please note: the ferrule is now permanently attached to the tube and can only be used in the aperture it is held in. Incorrect use can result in dead volume and leakage.
To properly tighten the pre-tightening stainless steel fittings, we recommend that you tighten the 1/4 or 3/4 buckle with a wrench after tightening the hand. If a leak occurs, tighten the fitting a little more until the leak stops. If the accessory still needs to be rotated more than one week after the hand is tightened, we recommend replacing it. If it is tightened too much, it will cause damage to the product.
Polymer material accessories
Unlike stainless steel fittings, polymeric material fittings are almost universal in equipment and relatively simple to use, so they are becoming more popular. The polymeric material fittings are not permanently attached to the tube and usually do not require any tools (except your fingers) to tighten. In addition, these accessories are manufactured from a variety of polymeric materials, offering a variety of price and solvent compatible options.
If your accessory leaks
1. Check the tubes to make sure they are connected. When connecting with a conventional hand-rotating fitting, the tube must pass completely through the fitting before being fastened with screws and ferrules. If the fitting is tightened after the fitting is tightened, the screw and the ferrule need to be reinstalled.
2. The accessories may not be tightened enough. Stainless steel screws and ferrules need to be fastened with a wrench even if they are used again. The hand-rotating fittings also need to be fastened, but wrenches cannot be used and the fittings will be damaged unless required by the instructions.
3. You may have used an incompatible accessory. Make sure the screws and ferrules you use are compatible with each other and with the accessories in the system. One way to avoid this problem is to use our universal hand-rotating accessories. Because the ferrule does not squeeze the tube forever, a hand-rotating fitting can be reused in most systems.
4. Check the condition of the screws and the ferrule. After repeated use, the screws (especially the ferrules) will gradually deform and eventually fail to achieve the designed sealing function. It's a good idea to have extra screws and ferrules so you can quickly change to avoid unnecessary work.
5. Sometimes the leakage is not caused by screws and ferrules, but because the receiving holes, especially those that are connected to stainless steel fittings, are more prone to leakage. Please check the accessories and threads for scratches that can be seen in time, and replace them if necessary.
6. If the material of the accessory you are using is not compatible with the mobile phase, it will definitely cause leakage and may cause permanent damage to the accessory.
TELL-TALE SIGNS system leak warning signal
Before you see the first drop of liquid leaking from the accessory, some signals will appear on the system telling you that something is wrong:
1) No flow, no pressure.
2) The pump pressure is increased, but no liquid flows.
3) Baseline noise.
4) Baseline drift.
Of course, these signals can also indicate problems that are completely unrelated to the leakage of the accessory, but it is easiest to start with the accessory first. The accessories are not only easy to repair but also the cheapest part of the system that can cause trouble.
Shanghai Qite Analytical Instrument Co., Ltd.: http://
telephone / fax
Http://news.chinawj.com.cn Submission:
Zhejiang Nanhua Electronic Technology Co., Ltd , https://www.nhloadcell.com