Maintenance method of elbow elbow

First, elbow bends talk

1. How to distinguish bend elbows

The difference between elbow and elbow is, in essence, the difference between "head" and "tube", but there are great differences in the production process. The most basic difference is that the elbow is relatively short compared to the elbow. R=1 times to 2 times is the elbow, and the larger multiple is called the elbow. In the production process, the cold bend tube can be bent with the ready-made straight tube bender, and the second-time completion does not require secondary anti-corrosion. The elbow should be made by the manufacturer, and the anti-corrosion should be made. The ordering period is long. The price of the elbow is higher than that of the elbow, but the cost performance is much higher than that of the elbow. The bend of the elbow without anti-corrosion treatment is well known, but it is because The price is very low in some projects that are not very demanding.

2. Elbow elbows are made of cast iron, stainless steel, alloy steel, calcined cast iron, carbon steel, non-ferrous metals and plastics. The way to connect with pipes is direct welding (the most common way) flange joints, threaded joints and Socket connection, etc.

3, elbow bend symbol: schxx is the wall thickness level, 90e (s) represents a short radius of 90 degrees elbow; 90e (l) represents a long radius of 90 degrees elbow; 45e (l) represents a long radius of 45 degrees elbow; 45e(s) denotes a short radius 45 degree elbow; 180e(s) denotes a short radius 180 degree elbow; 180e(l) denotes a long radius 180 degree elbow; r(c) denotes a concentric reducer; r(e) Indicates eccentric reducer joint; t(s) denotes equal-diameter tee; t(r) denotes reducer tee; cr(s) denotes equal-diameter tee; cr(r) denotes reducer tee; c denotes cap The classification method of the elbow is divided into its radius of curvature and can be divided into a long radius elbow and a short radius elbow.

The long radius elbow bend refers to the outer diameter of the tube whose radius of curvature is equal to 1.5 times, that is, R = 1.5D. A short radius elbow means that its radius of curvature is equal to the outer diameter of the tube, ie R = D. Where D is the diameter of the elbow and R is the radius of curvature. If there are about seventeen types according to the pressure level, they are the same as the American pipe standards: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, the most commonly used are STD and XS. According to the angle of the elbow, there are 45o elbows, 90o elbows and 180o elbows. In this way, there are many types of elbows. When ordering orders, the following methods are often used: "LR STD 90o 8", which means long radius, pressure level is STD, 90o 8"; elbow; and, for example, "SR XS 45o 4" means short radius, pressure rating is XS, 45o 4"; elbow.

Second, the elbow bend maintenance method

1. Long-term storage of elbow bends should be checked on schedule. The exposed surface should be kept clean, dirt removed, and stored neatly in a place where the air is dry and dry. It is strictly prohibited to be stacked or stored in the open air. The elbow is often kept dry and ventilated, the retainer is clean and tidy, and stored in an accurate storage method.

2. When installing, the elbow elbow can be directly installed on the pipeline according to the connection mode, and installed according to the position used. Under normal circumstances, it can be installed at any position of the pipeline, but it is necessary to facilitate the inspection of the operation. Note that the flow direction of the cut elbow medium should be upward from the longitudinal valve flap, and the elbow bend can only be installed horizontally. The elbow should pay attention to the sealing during installation to prevent leakage and affect the normal operation of the pipeline.

3. When the ball valve, globe valve and gate valve of the elbow elbow are used, they are only fully open or fully closed, and do not allow to adjust the flow rate, so as to avoid erosion of the sealing surface and accelerate wear. The gate valve and the upper thread stop valve have a reverse sealing device, and the hand wheel is screwed to the uppermost position to prevent the medium from leaking from the packing.