News and Information

　　 Quick-opening manhole What is the scope of application? Let’s take a brief look together. Quick‑opening manholes are auxiliary components commonly fitted to storage tanks, vessels, and water tanks, playing an indispensable role in ensuring safe operation and facilitating worker access for inspection and maintenance. When selecting a manhole, there are several key considerations to keep in mind, enabling you to procure a high‑value‑for‑money quick‑opening manhole at an affordable price while minimizing effort and hassle during subsequent use and upkeep. The applicable media for quick‑opening manholes include:

　　1. Ensure the rotary cover allows for quick opening of the manhole. Select the appropriate medium, working pressure, and temperature for the inspection port, along with the corresponding port style and material.

　　2. Once the nominal diameter, standards, and permissible tolerances for manholes have been specified and approved, manholes that meet these requirements may be selected.

　　3. Determine the structural configuration: circular manhole, elliptical manhole, rectangular manhole, etc.

　　4. The materials used for the main body of the inspection chamber include carbon steel, stainless steel, and others.

　　5. Precautions: When using the inspection port, users must wear shared protective goggles and verify compliance with requirements regarding the process medium, pressure ratings, explosion-proof standards, and corrosion resistance.

　　6. There are no special considerations for manual operations: room temperature, preservation, and the required height of the connecting section, among others.

　 　Quick-opening manhole Working principle:

　　1. When a quick-opening manhole is installed between two fixed supports on a pipe section, the thermal medium causes the pipeline to expand with temperature changes. This thermal expansion generates horizontal thrust on the two fixed supports. To maintain force equilibrium, the reaction force induces compressive deformation in the square compensator, thereby compensating for the stresses generated at the fixed supports due to thermal expansion.

　　2. To minimize deformation and stress during the operation of a rapidly opened manhole, the compensator must be pre‑adjusted to accommodate half of the thermal expansion.

　　3. Indicates the manufacturing position, installation position, and operating position of the inspection port. The diagram shows that when the compensator is compressed to half its compensation length (L), the stress in the compensator is zero (manufacturing position). If the compensator fully compensates for the thermal expansion, the fixed supports and the compensator itself will each experience only half of the total stress.

　　4. Therefore, when installing quick‑opening manholes, pre‑stretching is required. The pre‑stretch amount is L/2; accordingly, each side arm must be pulled out in advance.

　 　Quick-opening manhole What ensures the safety of storage tanks? Let’s take a brief look. Quick‑opening manholes are primarily used in industrial settings for large oil storage tanks and vessels, as well as for accessing items stored inside; they are typically employed in conjunction with fire‑protection equipment. If a quick‑opening manhole is activated during an accident involving a tank or vessel, it can lead to a dangerous buildup of internal pressure. Improper maintenance procedures may damage the tank and pose serious risks of injury or fatalities. In engineering applications, where tanks operate under high pressure, stringent quality standards are required throughout the manufacturing process of quick‑access manholes. For instance, the product must exhibit enhanced rigidity and superior sealing to prevent liquid leakage from the tank or vessel and withstand the applied pressure. Stainless steel materials should be selected with sufficient thickness to ensure they do not deform under pressure. Installation must strictly follow established procedures, and silicone rubber seals are commonly used on stainless‑steel manholes to prevent leaks of contained liquids.