What are the applications of flanged sight glass series, valves, and pipe fittings?

Flanged connections are widely used at the joints between pipes and pipe fittings or flanged equipment, for connecting pipelines and valves, and at locations where pipelines require disassembly for maintenance; they are typically employed for nominal diameters of DN50 and larger.

Based on the pipe‑joining methods recommended by manufacturers of various plastic and composite pipes currently available on the market, the following summarizes the connection techniques suitable for indoor water‑supply piping and their respective application ranges. Plastic and composite water‑supply pipes may be joined using rubber‑ring joints, solvent‑cement joints, heat‑fusion connections, fittings designed specifically for these materials, or flanged connections. When connecting plastic or composite pipes to metal fittings, valves, or other components, only dedicated fittings shall be used; threading is prohibited on plastic pipes.

Rubber joints are connecting fittings used to link pumps, valves, pipelines, and other equipment to piping systems. They typically come in three connection types: flanged, threaded, and clamp‑type. Flanged connections are the most widely used; they are bolted and nutted together to form a single unit and can accommodate a certain amount of angular misalignment, allowing for adjustments during installation and maintenance to match on‑site dimensions. Axial thrust is transmitted throughout the piping system during operation, which not only enhances operational efficiency but also plays a critical role in protecting pumps, valves, and other pipeline components.

Before installation, place the two pipe fittings to be connected on a horizontal surface. Begin by leveling the securely fixed end, then rotate the flange of the rubber expansion joint so that the flange holes align. Insert the bolts and tighten the nuts. Next, align the flange of the other pipe fitting horizontally with the flange on the rubber expansion joint, and rotate the flange of the expansion joint until the flange openings are properly aligned.

Household fire hydrants are in continuous operation, yet the external piping lacks effective connections such as flanges and valves, failing to meet safety and hygiene standards. Many flanges and valves are missing, some flanges on certain pipelines are severely corroded, and valves and fittings on others pose significant safety risks. Inspect whether the hydrant outlet is blocked; verify that flanges and valves have tight seals; and check for defects such as water leakage. Also assess whether there are issues like disorganized accumulation or other irregularities. The inspection revealed problems with the installation of concrete pipelines.

The double-flange force‑transmitting joint consists of a short pipe and flanges. It is a specialized fitting designed for the installation and removal of valves. Dual adjustment is employed during the lifting of heavy‑duty valves, particularly ball valves. The extended length of the flange‑type force‑transmitting joint widens the gap between adjacent pipes in the pipeline. After the valve has been lifted, a limit‑stop bolt extension can be installed to facilitate more precise valve positioning. During pipeline operation, the force‑transmitting joint effectively absorbs pipe‑induced stresses.

The North Bronze lug-type butterfly check valve HF-1280-80-11 is highly reliable. Valves designed with a self‑tightening sealing principle are typically used in high‑pressure applications. There are many different connection types for valves: some small valves can be welded directly to the pipe without removal, while non‑metallic valves often employ socket‑type connections, and so on. Users should select the appropriate type based on specific operating conditions. Both valves and pipe fittings are used in pipeline connections or control systems; neither can function independently—they complement each other. Valve and pipe‑fitting materials include carbon steel and stainless steel. GB/T 2499‑93 national standard: marine flanged cast‑iron double‑seat globe valve box.

The force‑transmitting coupling is primarily composed of a short‑pipe flange connected to the original double‑flange force‑transmitting coupling. It is a pipe fitting specifically designed for the installation and removal of valves. Double‑adjustment is employed during the lifting of heavy‑duty valves, particularly ball valves. The extended length of the flanged force‑transmitting coupling widens the gap between adjacent pipes in the pipeline. After the valve has been lifted, a limit‑stop bolt extension joint can be installed to facilitate more precise valve positioning. During pipeline operation, the force‑transmitting coupling effectively accommodates radial pipe displacement, but it does not absorb axial pipe movement.

1.4 Water supply plastic pipes and composite pipes may be joined using rubber‑ring joints, solvent‑cement joints, heat‑fusion connections, specialized fittings, or flanged connections. Connections between plastic and composite pipes and metal fittings, valves, and other components shall be made with dedicated fittings; threading is prohibited on plastic pipes.

Flanged connections involve securing two pipes, fittings, or pieces of equipment, each mounted on a flange, then placing a gasket between the two flanges and tightening them with bolts to create a tight seal. Flanged connections are typically used at main‑line junctions for valves, check valves, water meters, pumps, and other components, as well as in pipe sections that require frequent disassembly and maintenance. Larger‑diameter pipelines generally employ flanged connections. It should be noted that galvanized pipes, when joined by welding or flanging, must have the weld area re‑galvanized or otherwise protected against corrosion.

The force‑transmitting coupling is primarily composed of a short‑pipe flange connected to the original double‑flange force‑transmitting coupling. It is a pipe fitting specially designed for the installation and removal of valves. Double‑adjustment is employed during the lifting of heavy‑duty valves, particularly ball valves. The extended length of the flanged force‑transmitting coupling widens the gap between pipes in the pipeline. After the valve has been lifted, a limit‑stop bolt extension can be installed to facilitate more precise valve positioning. During pipeline operation, the force‑transmitting coupling effectively accommodates radial pipe displacement, though it cannot absorb axial displacement. Made of metal, this coupling is widely used in industries such as power generation, metallurgy, water supply and drainage, and wastewater treatment.

Steel–plastic flanged connections: When connecting to steel pipes and valves, flanged joints are recommended. The connection between the steel pipe end and the metal flange shall comply with the relevant welding specifications for steel pipes. Steel–plastic flanged connections with electrofusion: In electrofusion joining, the electrofusion fitting is first slipped over the pipe, after which a dedicated fusion welder applies current according to prescribed parameters (time, voltage, etc.), causing the inner surface of the electrofusion fitting—equipped with embedded heating elements—and the outer surface of the pipe’s insertion end to melt. Once cooled, the pipe and fitting fuse together. This method is characterized by convenient, rapid installation, high‑quality joints, and minimal susceptibility to external influences; however, electrofusion fittings typically cost several times, or even dozens of times, more than standard fittings. Saddle‑type butt joint connection 3 (the smaller the nominal diameter, the greater the mismatch).

Threaded socket connections may be used in piping systems with the following outside diameters, but they shall not be employed in systems conveying toxic or flammable media, nor in systems where service conditions could induce fatigue or severe corrosion. In carbon dioxide systems, threaded connections are permitted only within protected spaces and in the carbon dioxide cylinder room. ① Tapered‑threaded connections are suitable for Class I piping systems with an outside diameter not exceeding [value], and for Class II piping systems with an outside diameter not exceeding [value]. ② Parallel‑threaded connections may be used in Class III piping systems with an outside diameter not exceeding [value]. ③ Under special circumstances, dimensions larger than those specified above may be accepted, provided they meet recognized or standard requirements. Flanged connections involve securing two pipes, fittings, or components, each first mounted on a flange, placing a gasket between the two flanges, and then fastening them together with bolts to complete the joint. Some fittings and components already come equipped with integral flanges, which also constitute flanged connections. This type of connection is primarily used for joining cast‑iron pipes, rubber‑lined pipes, non‑ferrous metal pipes, and flanged valves.

In Langfang, 25‑kg stainless steel flanged rubber flexible joints achieve seamless, tight contact. When installed at the pump discharge and in pipeline systems as flexible rubber joints or expansion joints, if they are not equipped with anti‑pull‑out and limit devices—such as bolts—then during operation, the fluid pressure acting on pipe fittings like blind ends, valves, reducers, and elbows generates a thrust force known as “blind‑plate force.” This can cause the flexible rubber joint to expand or the expansion joint to elongate, potentially leading to lateral slippage and misalignment of the pipeline. Moreover, when the water pressure at the pump outlet is high, it produces a substantial axial thrust along the pipeline axis.

1. The valve body shall be clearly marked with: the manufacturer’s trademark, certification marks, the valve’s nominal pressure (or pressure class), the valve’s nominal size (or reduced‑bore designation), the material designation and heat number of the valve body, and the flow direction arrow for valves requiring a specific flow orientation. In addition, the standard series number of the connecting flange shall be stamped on the connecting flange (or on the straight‑pipe section of the connection).

A necked flange, also known as a split flange, is a type of flange. A flange is a component used to connect pipes to one another, typically mounted at the pipe ends. Flanges are equipped with bolt holes, and bolts secure two flanges together. The necked flange, along with its gaskets and fasteners, is collectively referred to as a flanged joint. Flanged joints are essential components in equipment and its parts, and they are indispensable in piping design as well as in fittings and valves. 1. Differences in appearance

Design institutes all have their own standards and corresponding pipe fittings. The selection of flanges is primarily determined by the properties of the process fluid and the operating conditions of the equipment. The type of sealing surface on a flange is likewise dictated by the process parameters. In short, the process conditions dictate whether flange standards are interchangeable. For example, the HG 20615 series and the American standard are essentially equivalent. Generally, flanges conforming to the HG 20595 series (the national standard B series) are widely used in most chemical plants; however, this standard is seldom employed in applications involving high pressure ratings.

North Bronze wafer-type butterfly check valve HF-1280-80-11, as well as PVC and other material options, with the first two being the most commonly used. In recent years, as living standards have improved, demand for food products has increased significantly, driving rapid development in the food‑processing machinery sector. Consequently, the production of stainless steel sanitary‑grade valves and fittings has flourished; when people refer to valves and fittings, they typically mean stainless steel sanitary‑grade products. Valves should be stored indoors in a dry, well‑ventilated environment, with both ends of the flow path sealed. Valves stored for extended periods should be inspected regularly. GB/T 1854‑93 national standard flanged cast iron single‑seat globe valve.