Which pipe seats of the steam boiler can be located within the range of the steam-water distribution plate?
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First, the main steam pipe must be above the steam-water separator. Here comes the question: which pipe seats can be located within the range of the steam-water hydraulic plate? Mainly the auxiliary air valve and the two safety valves – can they all be placed within the range of the steam-water separation plate, as long as there is enough space and the openings are properly reinforced? A steam separator plate is a long strip-shaped baffle with many small holes, located at the top inside the boiler.
Of course, the secondary valve is included. If there is really no other option, a safety valve can also be installed in that area; however, it is advisable to lengthen the valve pipe so that it extends beyond the separation plate.
Hey expert, extending the safety valve pipe means creating a hole in the separation plate – isn’t it better to use the separation plate to cover that hole?
By the way, what standards need to be met regarding the layout of these pipe sockets and pressure gauge socket, or are there any requirements specified in certain books?
The soda separation device (also known as a steam equalization device) has specific requirements regarding its openings: they cannot be too small, as this may lead to clogging, nor can they be too large, as this will result in poor quality steam. A simple analysis shows that this separation plate is a type of vapor-release-retarding plate with barrier properties. At the critical point of a boiler explosion, steam needs to be released instantaneously through the safety valve; it is therefore inappropriate to block the pipe of the safety valve inside the cover. Putting it another way, considering installation, if one wants to place the safety valve pipe inside without having to lengthen the pipe, it is necessary to make a slightly larger hole in the partition plate right where the safety valve is located. Note: Do not make any holes in the area where the main steam valve faces the separation plate.
Taking a horizontal fuel-gas boiler shell as an example (the layout of steam boilers is similar; it will not be discussed here to avoid comparison): ① The pressure gauge is usually located at the front, as it is more convenient to read the gauge from there； ②The main steam valve is generally located at the rear, as the quality of the steam in the steam space at the back is usually better. This was mentioned by an expert during a lecture; it seems to be based on empirical analysis and may also be related to hydrodynamic calculations of the boiler, though I can’t remember the details exactly ； ③Other pipe seats are arranged based on strength calculations: it is best if the spacing between them is larger, with a weld spacing of over 100 mm being ideal, and it is best if there is a distance of more than 150 mm between the welds and the access holes, and so on.
That’s wonderful! I’m in awe. Where can I find books with such content?
The standard steam separation plate is enclosed on all sides, and holes can also be made in this enclosure. There is another type of separation plate whose edges are connected to the top of the cylinder via reinforcing plates; these reinforcing plates do not pose any obstruction to the steam, so the surrounding area is completely open with no obstacles – only the orifice plate below functions. Is this reasonable? In my opinion, the effect of this plate isn’t too bad; it prevents water droplets from splashing upward, and there are already few water droplets that come in from the side. The separation plate of this structure allows any tube socket to be positioned within the range of the separation plate. Please, experts, clarify whether this kind of analysis is reasonable.
I’m here to reply to this post; such questions are very professional and technical, and I like them.
Soda separation is the process of removing water mist, and there are various methods (such as JBT9618, uniform vapor orifice plates, etc.). This water isn’t just the water that splashes out after it’s boiled; inside the boiler, the water droplets are flying around in all directions – it must be quite chaotic there. Saturated steam has the concepts of humidity and dryness. The goal is to install a simple device to ensure that the steam humidity meets the requirements (NBT47034).
I checked 9618, and it states that the length of the soda separation plate should not be less than two-thirds of the length of the boiler drum. That seems nonsense; there are no boilers like that. In boilers with a capacity of six tons, separation tubes are used, and in smaller boilers equipped with separation plates, the length is insufficient after taking into account the safety valve and access holes. It’s completely contradictory.