Fire pressure stabilizer pump equipped with metal expansion joint, wrong choice is really fatal
What is the metal expansion joint doing in the fire pressure stabilizer pump system? Don't just look at the name, it has to deal with three things at the same time: the vibration when the water pump is running, the length change caused by thermal expansion and contraction of the pipe, and the impact of the water hammer when the pressure stabilizer pump starts and stops. Ordinary rubber compensators can't withstand pressure fluctuations, age quickly, and many people leak in half a year. The metal corrugated expansion joint is the right solution, but the goods on the market are uneven-two days ago, I met a customer who installed a household metal hose cheaply. As a result, it cracked in less than half a year, and the fire acceptance almost failed. You say it was wrong or not?
Look at the working conditions first when selecting the model, don't joke about the parameters
The working pressure of the fire pressure stabilizer pump is usually between 0.6-1.6MPa, the temperature range is-20℃ to 80℃, and the medium is either clean water or foam mixture. Corresponding to our product line,Universal corrugated expansion jointAndMetal hoseBoth work, but the structure must come with a deflector-which is a hard indicator. The function of the guide tube is to prevent high-speed water from directly washing the root of the bellows. Many accidents lie in this detail. To put it bluntly, it is to add an armor to the bellows. I have written a detailed description of the specific function of the expansion joint guide tube before, so you can flip through the FAQ. In addition, the flange standard must match the pump group. Don't take the PN16 pump with PN25. It is easy to collapse when tightened. This is really not a scare.
Three pits, one is enough to step on
The first pit: use the expansion joint as an expansion joint, and pull it hard.The fire pipeline goes to the basement, and the space is limited. If the hole is not aligned during installation, someone will break it hard with a crowbar, and the bellows will be directly deformed, and the life will be cut in half. The correct way is to choose an expansion joint with a tie rod, such as oursUniversal corrugated expansion joint with limit tie rodLoosen the nut after installation. The function of the expansion joint tie rod is to limit the displacement and prevent overload during installation. This principle is similar to how to adjust the expansion joint tie rod nut in FAQ.
Second pit: Lateral displacement compensation is ignored.There are many turns in the outlet pipeline of the pressure stabilizer pump, and the metal expansion joint is best to absorb the lateral displacement.Compound hinge transverse expansion jointOrCompound straight pipe bypass pressure balanced expansion jointMore suitable for this kind of scenario. Think about it. When the pipe expands thermally, the horizontal direction will also move. How can the axial displacement of light absorption be enough?
The third pit: not counting fatigue life.The pressure stabilizer pump starts and stops dozens of times a day, and the bellows should be able to withstand at least 10,000 cycles. Don't choose the thin-walled one, save that little money and double the maintenance cost later. There are national standards for fatigue life: the metal bellows body implements GB/T 12777. All our products have been pre-stretched before leaving the factory, and the data can be checked. Before buying, be sure to ask the supplier for a fatigue test report. If you don't give it, you will know.
Pay attention to the installation position, and remember the formula
The expansion joint should be as close to the outlet of the water pump as possible, but it cannot be directly used as the load-bearing support of the pump. Add a fixed bracket at the front and a guide bracket at the back, with the spacing controlled at 4-6 meters. There's a formula:One end is fixed and the other is guided, and the middle expands freely。 Don't forget that the bolts on both sides of the expansion joint should be pre-tightened during the pressure test, and then loosen after the pressure test-it is the same as "Does the screw of the expansion joint need to be disassembled" written in our FAQ. If it is not disassembled, the pipe will be broken by thermal expansion. This point has also been emphasized in the correct installation method of large tie rod expansion joint, and the new construction team is most likely to make this mistake.
Maintenance is more worry-free than installation? Not present
The fire fighting system presses once a year, and by the way, check the appearance of the expansion joint: whether there are cracks in the weld, whether there are corrosion spots at the bottom of the corrugated valley, and whether the guide tube is loose. If you find signs of aging in the rubber compensator, don't hesitate to change it directly. The standard of metal expansion joint refers to JB/T 12235-2015 (non-metallic), but the metal bellows body has the national standard GB/T 12777. Our products are all based on this, and they have been pre-stretched before leaving the factory. Before you buy, you should ask the supplier for a fatigue test report. If you don't have one, you should know it in mind. In addition, the pressure standard of metal hose should also be checked. Don't use low-pressure pipe with high-pressure pump.
At the end of the day, this is a safety piece, not a consumable
The metal expansion joint of the fire pressure stabilizer pump, if you choose the right one for ten years, you don't have to worry about it, but if you choose the wrong one, you will drop the chain at the critical moment. What about that? Remember three things:Select type according to working condition, with guide tube and tie rod, and install according to standard。 The rest should be handed over to reliable suppliers-for example, we disclose the model, size and stiffness calculation formula of each expansion joint, at least we are not afraid of you checking it. The model and size of the expansion joint, the stiffness of the bellows and the calculation formula are available on the website. Welcome to compare. Alas, in the final analysis, fire fighting is no small matter, and don't fool a bolt or a bellows.