Some advantages of chemical-grade manholes

Storage tanks are commonly used in industries such as chemical processing, where they handle a variety of materials. During loading and unloading, the lids of atmospheric‑pressure manholes are frequently opened, allowing acidic substances to spill out and corrode the flanges. Even after repair, these flanges remain susceptible to re‑corrosion. Consequently, when repairing damaged flanges, it is necessary to install a plastic under‑flange; it is important to ensure that the plastic under‑flange matches the dimensions of the original flange.

In industries such as petrochemicals, various types of vessels equipped with manholes are commonly used, including pipelines, boilers, and downcomers. Operators enter these vessels through the manhole to perform maintenance and other tasks. While working inside, they typically secure the manhole to isolate the confined space from the external environment, thereby preventing unauthorized personnel from entering and mitigating potential safety risks. In existing practices, manholes on on-site vessels are usually sealed by having operators thread ordinary chains or wire through the bolt holes on the manhole face, wrap them in a figure‑eight pattern, then lock both ends of the chain or wire with padlocks. A warning tag bearing appropriate cautionary messages is subsequently hung on the lock to indicate that the manhole is secured and to serve as an alert.

Manhole structures and dimensions are generally standardized, allowing for selection or design based on relevant handbooks. Manhole doors open and close smoothly and conveniently, offering thermal insulation, easy and flexible operation, and resistance to deformation, making them well suited for applications in boilers, hot-air ducts, and similar systems. With the continuous advancement of modern production systems and the development of China’s machinery industry, power plants, chemical plants, and construction sites alike are increasingly seeking high‑quality, premium‑grade products such as atmospheric‑pressure quick‑opening handholes, atmospheric‑pressure manholes, and support‑and‑hanger components.

We boast state-of-the-art manufacturing processes, advanced production equipment, and comprehensive testing and inspection systems, offering a wide range of standard‑type manholes, drain ports, quick‑opening manholes, tank manholes, light‑transmitting openings, vent holes, air‑ventilation ports, elliptical manholes, boiler manholes, atmospheric‑pressure manholes, manhole doors, and more. In addition, we provide cutting‑edge ancillary facilities and technologically advanced products that are distributed nationwide. We also undertake custom fabrication to meet specific customer requirements. Hebei Chenrun Pipeline is a specialized manufacturer dedicated to supplying high‑end products and services to the petroleum, refining, chemical, metallurgical, power, shipbuilding, gas‑transport, and pipeline‑conveyance industries both domestically and internationally.

Pressure-relief manholes are safety‑emergency venting devices installed on petrochemical equipment and storage tanks. They are typically used in conjunction with breather valves mounted on the tank roof to maintain normal internal pressure, thereby preventing damage to the tank caused by sudden overpressure or vacuum conditions. These devices offer advantages such as pressure‑regulated discharge, reliable pressure control, flexible operation, a compact structure, excellent sealing performance, and high safety and reliability.

Most high‑tech equipment is derived from foreign designs; accordingly, such devices typically adhere to the American standard series, namely the HG20615 series. Our company primarily manufactures internal‑opening manholes, circular manholes, pressure‑rated manholes, valves, fittings, flanges, and heads. In response to market demand and industry trends, we continuously refine our business philosophy and place great emphasis on brand building, having now established ourselves as a reputable domestic manufacturer of light‑industrial machinery. Our products are widely employed across sectors including dairy, brewing, food processing, pharmaceuticals, beverages, and chemicals.

Male, 36 years old, a member of the general public, resident of Duli Town, Yindu District, and an employee at the oil depot of the Anthracene Oil Hydrogenation Plant; he served as the work team leader for this tank-cleaning operation. During hot‑work operations conducted by construction personnel at the leak point on the manhole cover of T4207 anthracene oil storage tank, he failed to inform the workers of the physicochemical properties of the tank’s contents and the associated risks, nor did he promptly halt the hot‑work activities. He bears direct responsibility for this accident. Given that he has already died in the course of this incident, it is recommended that no further accountability be pursued.

The main products of our flexible insulation garments include: valve insulation sleeves, exhaust pipe heat‑insulating sleeves, reactor jacketing, detachable insulation garments, plate heat exchanger insulation sleeves, manhole insulation sleeves, —‑machine insulation sleeves, injection molding machine insulation sleeves, detachable insulation sleeves, industrial insulation jackets, industrial insulation garments, detachable insulation garments, LNG cryogenic insulation systems, flexible detachable thermal‑insulation garments, detachable FRP insulation shells, premium nano‑thermal insulation products, thermal‑insulation panels, and protective suits for industrial robots. Our products are widely used in industries such as food processing, pharmaceuticals, petrochemicals, rubber and plastics, chemical engineering, thermal and nuclear power, shipbuilding, construction machinery, textiles, papermaking, metallurgy, and more, helping customers reduce costs and achieve significant economic benefits. We are a trusted partner for enterprises seeking to conserve energy, cut consumption, and implement effective industrial insulation solutions. Through ongoing research and field investigations, we have found…

The main products of our flexible insulation garments include: valve insulation sleeves, exhaust pipe heat‑insulating sleeves, reactor jackets, detachable insulation garments, plate heat exchanger insulation sleeves, manhole insulation sleeves, — machine insulation sleeves, injection molding machine insulation sleeves, detachable insulation sleeves, industrial insulation sleeves, industrial insulation garments, detachable insulation garments, LNG cryogenic insulation systems, flexible detachable thermal insulation garments, detachable FRP insulation shells, — nano‑thermal insulation products, thermal insulation panels, and protective clothing for industrial robots. Our products are widely used in industries such as food processing, pharmaceuticals, petrochemicals, rubber and plastics, chemical engineering, thermal and nuclear power, shipbuilding, construction machinery, textiles, papermaking, and metallurgy, helping customers reduce costs and achieve significant economic benefits. We are a trusted partner for enterprises seeking to conserve energy, cut consumption, and implement effective industrial insulation solutions. Organize soil condition assessments.

Male, 33 years old, a member of the general public, native of Huanghua City, Cangzhou, Hebei Province; shift leader at the oil storage facility of the Anthracene Oil Hydrogenation Plant of Henan Co., Ltd.; and the on-site supervisor for this operation. Due to inadequate safety management of hot‑work operations and insufficient on‑site safety oversight, coupled with lax management of outsourced workers, he left the hot‑work site without authorization when reporting to his superiors about the welding of the manhole cover on T4207 anthracene oil storage tank, failing to ensure that all personnel and equipment had been removed from the area and thus neglecting his duties as the hot‑work supervisor. On January 21, 2022, he was placed under residential surveillance on suspicion of the crime of causing a major accident due to negligence.

Six key features of market‑oriented polyethylene storage tanks: Rotational molding offers significant advantages, including excellent monolithic integrity with no welds—since the tank body, inlet, outlet, manhole, level gauge port, flanges, and other components are all integrally molded without seams, minimizing leakage of chemical liquids; leak‑proof performance; superior impact resistance; high tensile strength; good toughness; strong aging resistance; tolerance to extreme low temperatures; and resistance to most acids, alkalis, and both inorganic and organic solvents. Additionally, these tanks are hygienic and clean, with a long service life. This milestone marks the complete domestication of China’s technology for large‑scale full‑containment LNG storage tanks. The two 160,000‑cubic‑meter LNG storage tanks currently under construction are located at the Fujian LNG receiving terminal in Xiuyu Port, Putian. To ensure the successful delivery of 9Ni steel plates for this project, the company (stock code 000898) is coordinating relevant parties to advance work according to schedule. Once again, you can capture short‑term gains of 15%—simply scan the QR code to follow the YunCaijing WeChat subscription account.

On April 26, a poisoning and asphyxiation accident occurred during maintenance work in the ammonia synthesis shift‑change section, resulting in three fatalities and two injuries. The direct cause of the accident was as follows: During a major equipment overhaul, a nitrogen‑based system leak test revealed a leak at the manway of Shift‑Change Furnace No. 3. Without obtaining the required maintenance permit, the contractor’s maintenance personnel removed the manway cover to replace the gasket. The subsequent leakage of nitrogen into Furnace No. 3 led to the poisoning and asphyxiation incident.

On April 26, a poisoning and asphyxiation accident occurred during maintenance work in the ammonia synthesis shift‑change section, resulting in three fatalities and two injuries. The direct cause of the accident was that, during a major equipment overhaul when nitrogen was being used for a system leak‑tightness test, a leak was detected at the manway of Shift‑Change Furnace No. 3. Without obtaining the required maintenance permit, the contractor’s maintenance personnel removed the manway cover to replace the gasket, leading to a nitrogen leak inside Furnace No. 3 and subsequently causing the poisoning and asphyxiation incident.

Small-scale dairy fermentation equipment: food-grade milk fermenters and pasteurization fermenters are widely used in the dairy, beverage, bioengineering, pharmaceutical, and fine chemical industries. The vessel features a jacketed design with insulation layers, enabling heating, cooling, and temperature maintenance. Both the vessel body and the top/bottom heads (or conical sections) are formed using spin‑forming with rounded R‑corners, while the inner wall is mirror‑polished to eliminate sanitary dead zones. The fully enclosed design ensures that materials remain free from contamination throughout mixing and fermentation. The equipment is equipped with air breather ports, CIP cleaning nozzles, manholes, and other auxiliary components.

Six key features of market‑oriented polyethylene storage tanks: Rotational molding offers significant advantages, including excellent monolithic integrity with no welds—since the tank body, inlet, outlet, manhole, level gauge port, flanges, and other components are all integrally molded without seams, minimizing leakage of chemical liquids; leak‑proof performance; superior impact resistance; high tensile strength; good toughness; strong aging resistance; tolerance to extreme low temperatures; and resistance to most acids, alkalis, inorganic and organic solvents. Additionally, these tanks are hygienic and have a long service life. The port area’s annual crude oil handling capacity has reached 25 million tons. Shandong Province is home to more than 40 independent refineries and petrochemical enterprises, whose combined production capacity accounts for over 70% of the nation’s total independent refinery capacity. Since 2015, as China liberalized its import policies and international oil prices remained low, demand for imported crude oil among Shandong’s independent refineries has surged. In 2016, imports by Shandong refineries increased by 32% year on year, accounting for 65% of Qingdao Port’s total crude oil imports.