What are the various methods for opening holes under pressure in pipelines?c. When in-service pipelines need to add branch pipes, replace valves or undergo renovations, traditional stop-flow operations imply huge economic losses and environmental risks. The pressure-bearing hole-making technology achieves the goals of safe, efficient and environmentally friendly operations by completing the hole-making while the pipeline is in normal operation. So, how many methods are there for pipeline pressure-bearing hole-making? And which scenarios are suitable for different hole-making methods? This article will comprehensively explain the classification system of this technology for you. I. Overview of Pressure-Resistant Hole Opening Technology 1.1 What is Pressure-Resistant Opening? Pipeline pressure-bearing opening refers to a pipeline operation technique that involves machining a circular hole on an operating pipeline through mechanical cutting under a sealed condition or without interrupting production and without affecting the flow of the medium inside the pipeline. Through this technology, new pipe couplings, instrument installations, or equipment replacements can be completed during normal pipeline transportation, avoiding production losses and medium emissions caused by pipeline shutdowns. 1.2 Technical Features The pressure-bearing hole opening technology has the following remarkable features: · Advanced technology: Utilizes mechanical cutting method, eliminating the need for pipeline shutdown. · Pressure-resistant operation: Complete the hole-making process while the pipeline is in normal operation. · Flameless enclosed cutting: Eliminates the safety risks associated with hot work operations · Safe and reliable: Multiple layers of sealing protection ensure zero leakage · No pollution: The medium is completely sealed, achieving zero emissions. 1.3 Scope of Application The pressure-bearing hole opening technology is applicable to a wide range of working conditions: · Applicable pipe diameters: Steel pipelines, cast pipes, ductile iron pipes, PE/PVC pipes, etc., with diameters ranging from Ф22 to Ф1600. · Hole diameter: DN20 to DN160 · Applicable media: Oil, natural gas, water, ethylene, gas, medium-quality oil, aviation fuel, etc. (media without strong corrosive properties) · Medium temperature: -30℃ ～ +350 ℃ · Pipeline operating pressure: 0 - 10 MPa II. Classification by Driving Method The pressure-bearing hole-making technology can be classified into three main types based on the source of power. 2.1 Pressure-Resistant Manual Piercing Manual hole drilling is the most traditional and basic method of pressure-bearing hole opening. The hole opening machine is composed of drill rods, hole opening tools, differential feed mechanism, connecting disc, casing, protective sleeve and control handle, and it operates manually by human operators. Technical features: Cutting with the opening tool sleeve, with the drill pipe performing automatic differential feed The center drill on the hole-making tool centers the material and removes the cut-out piece. · Compact in structure, lightweight and portable, with simple and effortless operation Applicable scenarios: Manual hole drilling is mainly applicable to small-diameter pipelines (with diameters less than DN50), low-pressure conditions, and emergency repair operations where on-site power supply is inconvenient. Due to its flexible operation and lightweight equipment, it is particularly suitable for work environments with limited space. 2.2 Pressure-activated Pneumatic Opening The hydraulic perforation process uses a hydraulic system as the power source, and the hydraulic station provides stable driving force. In the high-pressure and high-sulfur perforation operation of the Shunbei Oilfield in the Northwest Oilfield, the technical team adopted the hydraulic drive method, cutting into the pipe wall at a slow speed of 10 revolutions per minute. Technical features: · High output torque and stable power performance · Capable of working continuously for a long time · Easy to implement overload protection · Wide speed adjustment range, large low-speed torque Applicable scenarios: Hydraulic hole opening is suitable for large-diameter and high-pressure pipeline hole opening operations, especially in scenarios where high power is required, such as long-distance oil and gas pipelines. Modern high-pressure hole opening machines have also added two sets of high-pressure balancing devices, enhancing the redundancy of the hole opening machine's balancing system. Even if one balancing system fails,