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Under what circumstances is it necessary to make an opening in cast iron pipes while they are under pressure? Pressurized pipe opening refers to the maintenance and emergency repair technique carried out while the pipeline is still transporting fluid; it is a safe, environmentally friendly, economical, and efficient method. As mentioned above, opening a pipe while it is under pressure is used only in situations such as pipe maintenance, emergency repairs, or route changes. In pipeline opening operations while the pipeline is under pressure, many types of pipelines are commonly encountered; classified by material, these include cast iron, ductile iron, ordinary steel, stainless steel, alloy steel, glass and fibers, PE (containing various reinforcing elements such as steel wires), PVC, cement, and other materials used in pipeline construction. Classified by the temperature of the transmission system: low-temperature pipelines, normal-temperature pipelines, and medium- to high-temperature pipelines. Protective management measures for pipelines generally involve adding a protective layer on the outside to prevent soil erosion and contamination. For underground metals, anti-rust treatments can be applied by using anti-corrosion coatings such as rust-proof paint, tar, or asphalt, or by wrapping them with materials like glass cloth and burlap impregnated with asphalt. Pipelines buried in highly corrosive, low-resistance soil should be equipped with cathodic protection to prevent corrosion ； Ground steel pipes are coated with various anti-rust paints to prevent corrosion caused by the atmosphere, rainwater, etc. During drilling operations on the pressing belt, these protective layers must be removed so that the exposed metal can show its luster. Next, let’s discuss the basic steps for making an opening under pressure: the operating procedure for making such an opening involves opening the gate valve to its maximum possible diameter. When the handwheel is rotated clockwise for feeding, the center drill (bit) moves to the top of the main pipeline; the reverse half of the handwheel serves to prevent the cutter from moving. Start the system’s hydraulic control pump station or motor, slowly turn the handwheel in a clockwise direction to advance the drill bit; once it feels as though the drill has penetrated the pipe wall, cut off the hydraulic supply or power supply. After cutting, one can manually reach the blade edge, indicating that penetration has been achieved. The operator turns the air supply wheel clockwise; the blade then moves slightly in a counter-clockwise direction at the top of the back wall of the barrel (to prevent the combat knife from moving). Restart the system’s hydraulic control pump station or motor, and slowly turn the handwheel clockwise to feed the tool in. The wall of the die-cutting tool handle, after the hydraulic supply is cut off or the power is turned off. After cutting, if the handwheel cannot be turned for manual feed, it indicates that the actual cutting has not been completed. The handwheel must be turned half a turn in the opposite direction, the system’s hydraulic supply must be reactivated or a power source must be started, before continuing with slow feed. When the motor’s power is cut off, the handwheel can still be turned to advance the feed, indicating that the hole-cutting process is complete. Equipment required for drilling under pressure includes a drilling machine: this machine consists of components such as drill rods, tool holes, a differential feeding mechanism, a housing, and a control handle; it also includes a tapping machine. This machine allows for manual hole opening, with the hole diameter being adjusted via a support frame. In the case of an automatic differential feeding drill, a central drill is used to create the central hole, and the cutting debris is removed accordingly. The entire machine features a compact design, small size, light weight, and is simple to operate. Plug: The plug consists of a main shaft, an eccentric connecting disc, a foldable rubber cup plug head, and a control mechanism; the components are made of specific materials. The implementation of the blocking device is a critical aspect; by cutting off the pipeline and preventing medium flow, it achieves the desired effect. Opening capability and reliability are key technical features of this device. It utilizes the eccentricity and spherical structure of the network-connected disc to swing a device that inserts the folding rubber seal into one side of the pre-made hole; the seal can be opened using a control lever, and the pressure in the pipeline continuously pushes against the conical rubber seal on the seal head, causing it to tighten further as it is sealed. Bottom plugger: The lower plugging device is composed of components such as the left and right clamping pieces attached to the main shaft coupling disc, as well as a control lever; its function is to seal the opening after inserting the special electrically fused PE pipe plug. Claws are mounted on the left and right main shafts at the bottom, and during the clamping operation of the seal plug for the fused PE pipe, there is a movable insertion pin, a gear for positioning, and an actuation mechanism on the main shaft. The above covers the situations in which it is necessary to make openings in cast iron pipes under pressure, the steps for making such openings, as well as an explanation of the equipment used for this purpose.