Maintenance of tank roof vent valves

I’m also thinking about this: is it simple to repair the breathing valve, so that it can be installed quickly, or should another one be replaced right away?

Let’s clear up the doubts @GuanGongYu @ZhiZheMing @BingXueHouQiu @XiaoGongTanHuaGong @ValveMingMing @ylb913 @jacques0920 *@nht1 @XiaoJie

I’m sorry, I’ve never seen a breathing valve before; I understand it to be a one-way valve for inhalation, designed to prevent the container from becoming vacuumed. Could a shut-off valve be installed in front of it?

This post was last edited by ylb913 on 2016-3-10 21:04. I haven’t used a exhale valve either, but I can have some ideas of my own. A breathing valve allows for both exhalation and inhalation; what is inhaled is usually air (air is inhaled only under very special circumstances when the system is pressurized with nitrogen). As for what is exhaled, it can be oil-gas or nitrogen of high purity at times, or it can be explosive gases containing a large amount of air and low levels of oil-gas. Compared to venting the water seals in sulfur-containing wastewater tanks, I have more experience with handling that process. To avoid harm to people due to the sulfur content in the wastewater, we usually carry out these operations in the afternoon when there is negative pressure inside the tank (there is an indoor pressure display on the top of the tank, with the normal pressure range being -500 to 2000 Pa). Regarding other situations, my understanding is as follows: 1. In necessary cases, air respirators can be worn and explosion-proof tools can be used. 2. It is very necessary to carry out maintenance checks on the breathing valve, especially when there is no pressure indicator on the tank top. However, checking it once every half month is not practical; initially, these checks can be done more frequently, and as experience is gained, the interval between checks can be increased, with this being specified in the relevant regulations. 3. It is possible to find out which vent valves on those medium storage tanks are prone to getting clogged and which are not; this can be learned from relevant organizations, or by actively accumulating experience.

For the single-exhaust valve, a slight positive pressure is maintained inside the tank; this is related to the weight of the valve element. A nitrogen seal is usually installed. The single-intake valve is used primarily to prevent the pressure inside the tank from dropping; when the pressure falls below the set value of the single-intake valve, air is introduced into the tank to prevent it from deforming. Maintenance is also quite simple, as the pressure remains low, around 2 kPa, and generally only the weight of the valve element needs to be cleaned

The breather valve has been installed; I haven’t dealt with its maintenance yet, so I’m here to learn about it*

I hope fellow sailors can help clarify this. By the way, how do you all handle leaks in breathing valves that occur at work? And what are the causes of frequent leaks and the corresponding remedial measures? Thank you very much. . .

It isn’t necessary to conduct inspections that frequently; the main thing is to keep the liquid level in the storage tank within the specified range, and generally, deformation of the tank does not occur.

Breather valves can be divided into many categories (search on Baidu). I have used: All-weather flame arrestor breathing valves, breathing valves with an exhaust port. 1. All-weather type breathing valves: These are a type of breathing valve; as the name suggests, their mechanism is similar to that of flame arrestors installed on pipes – sparks are immediately extinguished to prevent accidents. Normal breathing is possible, and these valves are used to assess the properties of the material (gases that can be discharged directly). They are installed at the ventilation holes on top of storage tanks to release gases into the atmosphere ； 2. Breathing valve with an exhaust interface: It contains a spring mechanism similar to that of a safety valve, along with a set value; it is installed at the vent hole on top of the storage tank. The exhaust interface is connected to the exhaust gas recovery system. The storage tank is equipped with a nitrogen seal – for example, the set value might be +100/-30 mm of water column. When the pressure in the tank exceeds 10 kilograms, the breathing valve will automatically activate to release gas into the exhaust gas recovery system for further processing ； If there is a negative pressure vent valve in the tank, it will activate to draw in air and maintain the internal pressure of the tank ； Finally, the exhaust gas is treated and then recovered or released in accordance with regulations ； Regarding the maintenance issues you mentioned: would it be okay to install blind plates and remove them for maintenance? It generally doesn’t take very long. Besides, don’t storage tanks have control valves for the nitrogen sealing system? If the pressure inside the storage tank becomes too high, the pressure sensor located downstream of the control valve will automatically shut off, preventing nitrogen from flowing in unchecked and thus increasing the pressure inside the tank ；

This post was last edited by zhengxue on 2016-3-19 22:49. The maintenance of breathing valves requires the development of maintenance and repair plans based on the way they are used by users; there is no one-size-fits-all approach to maintenance. We do not recommend repairing or removing breathing valves while the system is in operation, as this requires shutting down the system to check for flammable and toxic gases. It is also not advisable to use blind plates as a substitute for breathing valves. The maintenance and cleaning of the breathing valve must be carried out in a clean room. To put it simply, for more detailed information please contact us by visiting the Finekay® official website or by calling us.