Why does the pressure gauge have to have a 'bend'? Old engineer: Without it, the readings are all deceiving you
In industrial pipelines, fire protection systems, and other scenarios, pressure gauges are the "eyes" for monitoring pressure, and observant people will find that there is always a bend where the pressure gauge connects to equipment and pipelines.
This seemingly simple design actually hides a lot of knowledge.
The scientific name of this bent pipe is "pressure gauge buffer pipe", and construction personnel are more accustomed to calling it "pressure gauge pipe bend". There are mainly two forms: circular bend and U-shaped bend, among which the U-shaped bend is more memorable due to its intuitive shape.
Don't underestimate this bend, it is the "guardian angel" that ensures the normal operation of the pressure gauge
Its core role is reflected in two aspects.
On the one hand, it can cushion pressure shocks. The liquid or gas flowing in the pipeline often experiences pressure fluctuations, ranging from fluctuating readings on the pressure gauge to sudden impacts on the gauge head, resulting in damage to internal components.
With a buffer tube, the fluid pressure will first go through the "buffer treatment" of the bent pipe, greatly reducing the impact force and avoiding damage to the pressure gauge caused by "hard hitting".
On the other hand, it can ensure accurate measurement. When pressure fluctuations directly affect the pressure gauge, the reading will be distorted; The buffer tube can stabilize pressure transmission, allowing the pointer to swing smoothly and ensuring that the data reflects the true pressure state.
This design concept does not come out of thin air, and similar principles are also reflected in the design of pressure relief holes abroad. Essentially, it is achieved through a simple structure to protect precision instruments, which demonstrates the wisdom of "simplicity over complexity" in engineering design.
In addition to buffer tubes, there are many specifications for the installation of pressure gauges, and different systems have their own requirements:
In the fire pump system, both the suction pipe and the discharge pipe need to be equipped with pressure gauges.
The pressure gauge on the outlet pipe not only needs to be equipped with a buffer device, but also needs to be fitted with a plug between the two, with a range usually 2-2.5 times the system working pressure;
If a pressure gauge is installed on the suction pipe, the range should not be less than 0.70MPa, while a vacuum gauge is usually -0.10MPa. At least 2 pressure gauges with an accuracy of not less than 1.5 levels and a range of 1.5-2 times the test pressure are required for pressure testing.
In the fire pump system, both the suction pipe and the discharge pipe need to be equipped with pressure gauges. The pressure gauge on the outlet pipe not only needs to be equipped with a buffer device, but also needs to be fitted with a plug between the two, with a range usually 2-2.5 times the system working pressure;
If a pressure gauge is installed on the suction pipe, the range should not be less than 0.70MPa, while a vacuum gauge is usually -0.10MPa. At least 2 pressure gauges with an accuracy of not less than 1.5 levels and a range of 1.5-2 times the test pressure are required for pressure testing.
These seemingly cumbersome regulations are actually aimed at ensuring stable and accurate operation of pressure gauges under various working conditions.
From a small buffer tube to detailed installation specifications, every design embodies safety considerations.
After all, in industrial production and fire safety, accurate pressure data may be the key to avoiding significant losses
