I will explain the shape of the tank nozzle . It is also called a pipe stand.
It is the connection between the tank and the pipe .
As long as the tank and the pipe are connected without thinking about the nozzle, right? I tend to think.
Mechanical equipment design engineers of chemical plants show great commitment here .
I would like to introduce a summary of the obsessions that are completely unnoticed by anyone other than mechanical equipment design engineers.
As a designer, it is precisely the parts that go unnoticed that are “obsessed”
top plate nozzle
The idea changes depending on which part of the tank the nozzle is attached to.
Let’s start with the top plate nozzle .
gas nozzle
The substance passing through the nozzle is divided into gas and liquid .
Start with gas.
When passing gas through the nozzle, use a simple structure as shown below.
Attach a pipe called a nozzle to the top plate, attach a flange , and you’re done.
Nitrogen/gas lines are applicable for batch.
liquid nozzle
The nozzle through which the liquid passes is usually drop type .
You may also call it a dip tube .
welded connection
There are several reasons for choosing the drop type.
Advantages of drop type
- easy to clean
- cause fire explosion
- Puddles affect reaction performance
Non-drop type nozzles, which are usually considered simple, are just a nozzle attached to the top plate.
When liquid is passed through here, part of the liquid travels along the ceiling surface of the top plate.
Where on the ceiling the liquid is transmitted depends on the shape of the tank and the installation situation.
All I can say is that it is difficult to clean up later.
I use the drop type in the sense that I want to limit the part where the liquid is transmitted anyway.
Leaving the remaining liquid on the ceiling may lead to a fire explosion depending on the thermal stability of the liquid .
If the liquid left on the ceiling fluctuates from batch to batch, even a small amount may cause fluctuations in the reaction performance .
The manufacturing department wants to stabilize the results as much as possible and narrow down the fluctuation factors.
It’s a small thing, but you can dramatically improve reliability by making it a drop type.
The idea is the same not only for liquids but also for powders.
For metal tanks , the nozzle is attached directly to the top plate by welding.
insertion tube
Insertion tube type parts are attached to non-drop type nozzles if you want to realize drop type later .
It is sometimes called a drip tube .
In this case, the cross-sectional area is one size smaller than the nozzle body.
Care must be taken as the flow velocity increases and the pressure loss increases.
Glass lining equipment and Teflon lining equipment are often only compatible with drip pipes.
If a reducer is attached, the drip pipe should be attached to the tank side of the reducer.
The idea is that the drip pipe is part of the tank, not part of the piping.
If the insertion tube is too long
Extra care is required when the insertion tube is very long.
If the insertion tube is long, it will easily vibrate when the liquid flows .
It can’t be helped because it has a cantilever structure that supports only the top.
In order to suppress this as much as possible, there are cases where the side plate is used as a vibration stop.
A long insertion tube means that liquid with high pressure falls down, so the bottom plate may be reinforced.
If the plate thickness is small, such as an outdoor tank, it may be deformed.
If the insertion tube is long, the insertion tube may be completely submerged in the liquid inside the tank.
This situation can be quite disturbing.
This is because the inside of the tank may become pressurized negative pressure, or the liquid may flow backward depending on the pressure state of the connected tank.
If there is no particular preference, a hole is made in part of the insertion tube to prevent backflow.
It’s a small thing, but it has the effect of avoiding even a little bit of unpredictable trouble.
Care should be taken when a very small amount of dripping is required for reaction in a stirring vessel, etc., and a small diameter of the insertion tube is desired.
If the strength of the insertion tube cannot be secured, the insertion tube may break due to the stirring flow.
In such a case, countermeasures such as double insertion of a large diameter insertion tube and a small diameter insertion tube may be taken.
side plate nozzle
Bottom plate nozzles generally have a simple shape as shown below.
Reinforcement
The important thing about the side plate nozzle is the strength around the nozzle.
A tank nozzle has piping and valves attached to it, and a moment is generated around the nozzle.
This moment can cause problems such as cracking of nozzles and welds .
As a countermeasure, there is only reinforcement, so the following reinforcement is applied.
The choice is whether to add a backing plate to increase the thickness of the tank itself , or to reinforce it with ribs .
There are few elements to worry about ribs.
thermometer
A thermometer may be attached to the side plate.
In this case, it is better to attach the thermometer protection tube in the same way as the insertion tube.
Some thermometers themselves have such a protective tube function.
Accumulation prevention
When attaching a nozzle to an inspection port that is not normally used , it is recommended to attach a lid to prevent accumulation.
Rather than the nozzle, it corresponds to the blind flange side attached to the nozzle.
The idea is the same as the thermometer protection tube.
Especially in powder hoppers, this may be done.
If you want to reduce pooling, you may attach the flange directly to the tank by welding.
You may also call it a pad flange .
suction type
The suction type may be used for the side plates of flat-bottomed tanks .
I can’t put the nozzle on the bottom of the tank, but I try to get the nozzle as low as possible.
Even so, the position of the nozzle will be a certain height from the bottom plate, and the liquid will accumulate.
The idea is to add a suction nozzle in order to reduce liquid pooling as much as possible.
This will make cleaning the inside of the tank a little easier.
bottom plate nozzle
The bottom plate nozzle has a simple shape.
I just changed the direction of the gas system of the top plate and the side plate as it is.
Exceptionally, there may be cases where the pad flange taken up on the side plate is used.
This is because troubles such as clogging due to accumulation of powder in the nozzle are likely to occur.
The pattern of attaching a piston valve to the pad flange is quite common.
reference
Nozzle design is directly linked to piping design.
Nozzle design occupies a considerable weight in tank design, so I would like to consider it thoroughly when designing piping.
lastly
I explained the shape of the tank nozzle collectively.
It is classified into top plate, side plate, bottom plate, and elements such as liquid gas, insertion tube, and reservoir.
Nozzle shape is an important part of tank design. Let’s be able to use properly.
Please feel free to post your worries, questions, and questions about the design, maintenance, and operation of chemical plants in the comments section. (The comment section is at the bottom of this article.)
*I will read all the comments and answer them seriously.