Questions regarding the use of vent valves and flame arrestors

　I. Introduction Oil storage tanks are important equipment in the petrochemical industry, and breather valves, as safety accessories on these tanks, are given considerable attention. Changes in ambient temperature inevitably lead to changes in the pressure within the gas space of oil tanks; therefore, a breather valve is needed to maintain a certain pressure level in order to reduce minor breathing losses in the oil tanks. During oil transfer operations, breather valves can also reduce the significant evaporation losses in oil tanks. Therefore, within a certain pressure range, breather valves not only help to minimize the evaporation of oil but also play a role in ensuring the safety of the oil tanks. Breather valves are essential safety accessories for storage tanks, as their function is to reduce the evaporation of volatile liquids in tanks operating at normal or low pressures. Installing a vent valve not only helps to reduce gas emissions from the tank, thereby minimizing pollution of the atmosphere, but it also prevents the storage tank from being damaged due to overpressure or from becoming unstable as a result of excessive vacuum. This contributes to both safety and environmental protection. II. Principle of operation of the breather valve: The breather valve is an important accessory for ensuring the safety of oil tanks. Installed on the top of the tank, it is used to automatically control the opening and closing of the gas passage between the inside and outside of the tank, thereby maintaining pressure balance within the tank. It protects the tank against overpressure or undervacuum conditions, and it can also reduce the evaporation losses of the oil to a certain extent. A breather valve uses the weight of a valve disc (sometimes with a weight attached to it) to control the exhaust pressure inside the tank and the vacuum level during inhalation. When the pressure of the gas inside the tank exceeds...? (This article has 3 pages in total) Read the full text >> The breathing valve is one of the main accessories widely used on fixed-roof light oil tanks; it is used to control the exhaust pressure and the suction vacuum level of the storage tank. To prevent the pressure or vacuum level from rising above allowable values, which could cause damage to the tank. Due to pressure control, oil evaporation loss is also reduced to a certain extent. Currently, the commonly used types of fire-resistant breathing valves are the Soviet-style mechanical type, the 68-1 type, and the 68-IA type. In cold regions, breathing valves are used in combination with hydraulic safety valves. Their common drawback is that there is a hard contact between the valve disc and the valve seat, resulting in high leakage rates; this problem is particularly severe when the valve disc becomes corroded and deformed due to lack of maintenance over time. Additionally, since the hydraulic safety valve often sprays oil, water accumulated at the bottom tends to freeze in cold regions during winter. To prevent destructive accidents caused by the freezing of the valve disc leading to tank damage, the valve disc is usually removed, allowing the light oil in the tank to be stored at atmospheric pressure; this results in significant losses of oil. Therefore, research and improvement should be carried out on breather valves, with new types of breather valves designed to suit various environmental conditions and media, in order to meet the different needs of users. I. Structure and Characteristics of All-Weather Breather Valves. The original name of the all-weather breather valve was Type 82-N breather valve. The decisions regarding its structure and material selection were made in response to the problems associated with the Type 68-IA breather valve at that time: the valve disc tended to deform when heated, leading to gas leakage from the tank; springs would rust or frost over, and so on...? (This article has 9 pages in total.) Read the full text >> The fire-blocking performance of pipeline flame arresters must meet the requirements specified in GB13347 “Fire-Blocking Performance and Testing Methods for Petroleum Gas Pipelines”. Article 4.1.12 of the “Design Code for Petroleum Storage Tanks” stipulates clearly that “fixed oil tanks used for storing Class A and B oils as well as light diesel must be equipped with flame arresters and breather valves”. I would like to share my personal views on how to choose vent valves and flame arrestors for reference. In the early years of the founding of the country, vapor, coal, and diesel storage tanks in military fuel depots were equipped with breather valves and flame arresters. Due to historical constraints, it was necessary at that time to install both a mechanical vent valve and a hydraulic safety valve on a storage tank simultaneously. A mechanical breathing valve is used for the breathing of oil tanks, while a hydraulic safety valve comes into action when the mechanical breathing valve fails, serving as a backup mechanism. Flame arrestors used metal mesh flame arrestors or gravel flame arrestors, which was the correct approach at that time. Later, it was found during the operation of the oil depot that the sealing fluid of the hydraulic safety valve tended to spill out very easily, requiring timely replenishment; moreover, the sealing fluid had to be replaced after some time, which made management inconvenient. Although manufacturers later made improvements to the product design, enhancing the quality and basically resolving the oil spraying issue, problems such as oil filling and oil replacement still existed; as a result, hydraulic safety valves were generally not popular. In the mid-1960s, many facilities removed the hydraulic safety valves and kept only the mechanical vent valves; this was acceptable in the south, but it was very dangerous in the north. The former standard of the Ministry of Petroleum Industry (SY7518–87) specified that the operating temperature for GFP-type (standard) vent valves was 0…? (This article has 2 pages in total.) Read the full text >> Pipe flame arrestor models: GZW-1. The GZW-1 type of flame and explosion arrestor is a new type of flame arrestor for combustible gas pipelines, representing an upgraded version of this product. This flame arrester has been tested jointly by the University of Science and Technology of China and the Tianjin Fire Science Research Institute of the Ministry of Public Security, and its performance fully meets the requirements specified in GB13347-92 \"Flame Arresting Performance and Test Methods for Petroleum Gas Pipelines\". The flame arrester has a reasonable structure, with an effective flame-arresting layer. 　　A breather valve is an important accessory for ensuring the safety of oil tanks; it is installed on the top of the tank and consists of a pressure valve and a vacuum valve. Its function is, under normal circumstances, to maintain the integrity of the oil tank and to reduce oil evaporation losses to a certain extent. And when necessary, it can automatically regulate ventilation to balance the pressure inside and outside the oil tank, thereby ensuring its safety. When the pressure of the oil and gas inside the tank exceeds the allowable pressure for that tank, the oil vapor escapes through the pressure valve; at this time, the vacuum valve is in a closed state ； When the pressure of the oil and gas inside the tank is lower than the allowable vacuum level for the tank, fresh air enters the tank through the vacuum valve; at this time the pressure valve is closed, and the allowable pressure (or vacuum pressure) is controlled by the weight of the adjustment disc. ? A flame arrester vent valve refers to both a vent valve and a flame arrester; these two components are used together, but they can also be used separately.