Regarding the location of the manhole device
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The manway device at the upper part of the boiler drum in ordinary boilers is usually located at the front of the boiler. There is currently a hot water boiler equipped with a flat tube sheet. Since the flue gas temperature is high at the front tube sheet, in order to prevent cracks in it, it is intended to locate the outlet pipe seat at the front part of the boiler, so that the boiler water flows toward the front tube sheet and thus improves the flow conditions there. Well, if the manway is still placed at the front, it will interfere with the water outlet device. My question is: why are manways generally located at the front of the boiler? Can they be placed near the rear tube sheet? I would appreciate your advice.
Most shell boilers are equipped with a manhole all over the shell; if the structure permits, another manhole or access hole can also be provided on the rear tube sheet； The manholes for water-tube boilers are all located on the drum head. So not all boiler manholes are located at the front of the boiler; only those of vertical water-tube boilers are placed at the front. Larger boilers have one manhole at each of the front and rear sides.
It’s not necessarily located at the front of the drum, but it’s also not necessarily at the back; generally, there is an access hole on the rear tube sheet. In shell-and-tube boilers, access to the lower part of the smoke tubes is provided through the access hole on the rear tube sheet, and the access hole in the drum doesn’t allow inspection of the lower part of the drum
For WNS-type fuel-gas boilers, the manholes must be located on the boiler shell; there are no specific requirements regarding their exact position, but they cannot be placed too close to the front or rear tube sheets. Due to the constraints imposed by the diagonal support rods, they are generally installed in the middle section of the boiler shell! In the case of steam boilers, the main steam valve is generally installed above the reburning chamber located near the furnace shell; it can also be placed near the front tube sheet. There isn’t much space available for installing manholes in this area, so the manholes have to be placed in the middle of the boiler, as there is no space at the back. The same applies to hot water boilers – the water inlet is also located near the reburning chamber, and again, there isn’t enough space for manholes
Our company’s boilers have upper and lower water drums, with manholes provided on the front and back of both drums. If you want to open the manhole by yourself, it will be a huge project that requires the involvement of a professional boiler manufacturer; moreover, the related procedures will be extremely troublesome, and the costs will be astonishing.