First, the gate valve Gate valves, also called gate valves and gate valves, are widely used valves. Working principle: The sealing surface of the ram and the sealing surface of the valve seat are smooth, flat and consistent, and processed into a very close and tight sealing pair. The gate is turned on and off by the lifting and lowering of the valve stem to form a turn-on and turn-off of the medium. It acts as a shut-off in the pipeline. Advantages: the fluid resistance is small; the sealing surface is not eroded when fully open; it can be used in the case of two-way flow of the medium, no directionality; strong and durable; not only suitable for small valves, but also for large valves. Disadvantages: high height; long opening and closing time; cumbersome; difficult to repair; if it is a large diameter gate valve, manual operation is more laborious. The gate valve is divided into the rod type and the dark rod type according to the different stems; the parallel structure and the wedge type according to the structure of the gate; and the division of the single gate and the double gate. Second, the stop valve Globe valves are also widely used valves. Generally, the caliber is below 100mm. It works like a gate valve, except that the closing member (valve) moves along the centerline of the seat. It acts as a shut-off in the pipeline and also allows a rough adjustment of the flow. Advantages: easy to manufacture, easy to maintain, durable. Disadvantages: Only allow the medium to flow in one direction, and have directionality during installation. Large flow resistance and poor sealing. According to the structure, it is divided into straight-through type, right-angle type, direct current type and balanced type. Flange straight-through (J41H) and internally threaded straight-through (J11H) are generally used in engineering. The shut-off valve is directional and cannot be reversed. It is not advisable to fall down. Third, the ball valve Compared with gate valves and globe valves, ball valves are a new type of valve that is gradually being widely used. Its working principle is: the valve core is a sphere with a through cavity, and the valve core is controlled by the valve stem to rotate 90° to make the valve unblocked or blocked. It acts as a shut-off in the pipeline. Advantages: In addition to the advantages of gate valve and globe valve, it has the advantages of small volume, good sealing (zero leakage) and easy operation. Currently widely used in petrochemical, electric power, nuclear energy, aviation, aerospace and other departments. Disadvantages: Maintenance is difficult. Ball valves come in two forms: floating ball and fixed ball. Fourth, butterfly valve Butterfly valves are currently the most widely used and most widely used type of valve in heating systems. Working principle: The valve disc is a disc that rotates through the valve stem, and the valve flap rotates at 90 °C within the valve seat to realize the switch of the valve. It acts as a shut-off in the pipeline. The flow can also be adjusted. Advantages: simple structure, light weight, convenient operation and good sealing. Disadvantages: When fully open, the valve plate (seal) is subject to media erosion. In the heating project, the butterfly valve used has three eccentric metal sealing butterfly valves and rubber soft sealing butterfly valves. Five, check valve The check valve is also called a check valve and a single flow door. A commonly used auxiliary valve. Working principle: relying on the force of the fluid itself and the weight of the valve flap, the valve is automatically opened and closed. As its name suggests, its role is to prevent media from flowing backwards. Generally installed at the pump outlet to prevent water hammer from damaging the pump. Commonly used in heating projects are horizontal lifting (H41H), single-lobed swing (H44H), double-lobed butterfly (H77H). Sixth, the regulating valve Also called the throttle valve. It is a common valve for the secondary network of the heating system. Working principle: The shape and structure are similar to the stop valve. Only the sealing pair is different. The valve flap and the valve seat of the regulating valve are similar to the stopper and the bottle mouth of the thermos bottle, and the flow area is adjusted by changing the flow area by the movement of the valve flap. A scale on the valve shaft indicates the corresponding flow. Function: Adjust the medium flow distribution between pipelines to achieve thermal balance. Straight-through (T41H) has been used in heating engineering, but it has some disadvantages: it has a large flow resistance and should not be installed vertically. Thus, as technology advances, the balancing valve (PH45F) replaces the regulating valve. Seven, balance valve Improved regulator valve. The flow channel adopts a direct current type, and the valve seat is changed to polytetrafluoroethylene; Overcome the shortcomings of large flow resistance, and at the same time add two advantages: the seal is more reasonable, and has a cut-off function. It is used on the secondary network of the heat station in the heating project and has excellent flow regulation characteristics, especially suitable for variable flow systems. Directional, can be installed horizontally or vertically. Self-operated balancing valve Self-operated balancing valves are also called flow control valves. It works by having a mechanism consisting of a spring and a rubber membrane inside the valve that is connected to the valve stem. If the flow rate increases, an imbalance force is generated on it, causing the flap to move in the closing direction to reduce the flow area, reduce the flow rate, and return the flow to the set value. vice versa. Therefore, the flow rate after the valve is always kept constant, and the flow rate is controlled. The hot population installed at the heating system, the branch point. Automatically eliminate hydraulic imbalance, improve system efficiency and achieve economic operation. Self-operated balancing valves are directional and must not be reversed. Nine, safety valve When the medium pressure exceeds the specified value, the valve can automatically open and release pressure. When the pressure is normal, it can automatically close to ensure the normal operation of the system. The valve functioning as this function is called a safety valve. According to the structure: spring type, lever type, pulse type. According to the amount of action: 10% of the ratio of the valve opening height to the valve seat diameter is called micro-open type, 20% to 30% is called full-open type. According to the way of excretion: the medium is discharged through the pipeline and is called closed type, and is directly discharged into the air and called open type. JINAN LODOR CNC EQUIPMENT CO.,LTD , https://www.zgfireplace.com