The slipknot is convenient, and the survival length is short, and there is one less thread opening than the thread. Use the right yarn to wrap the raw material tape around both ends, and only use one piece of yarn for the slipknot.
Further question: It seems that the left side of the picture requires the use of two tools, an adjustable 6-angle wrench and a large pipe wrench, to tighten it. The union is too big. On the right side of the picture, you can just use an adjustable 6-point wrench. It feels like there is a rubber washer inside the outer wire union on the left side of the picture, but a raw material tape is needed when it is tight.
Follow-up answer: The one with the pair of threads is called the inner thread slip knot, which is used to connect the immovable outer thread. Generally, if there is an outer thread, use the inner thread slip knot, and if there is an inner thread, use the outer thread slip knot. No need for the right thread. Silk
Direct is a simple straight tube. The cost is low. Both ends of the union are threaded, but the cost is high. But in some cases it cannot be used directly. For example, a water meter or valve needs to be connected in the middle of a pipeline. Without a union, it would be difficult to weld the water meter or valve on.
The difference between the PPR ball valve and the PPR union ball valve is that there is a (hot melt) union and (link) nut between the two sides of the PPR union ball valve and the pipe (hot melt). , it is convenient to disassemble and replace the valve during maintenance. The PPR ball valve does not have this union and can only be sawed off during maintenance.
360 Q&A
What is a PPR pipe union and when should it be used?
namewenjie LV10
2017-12-15
Satisfactory answer
mhujp3a1vro7
LV8
Recommended on 2017-12-16
The union is easy to replace, but The price is more expensive than ordinary ones.
In fact, loose joints are indeed used less, especially in the south, and more in the north. In addition, loose joints are flexible in installation and disassembly, which can facilitate future maintenance, etc., but loose joints The cost is relatively high, so most people will still use the direct method. After all, direct method can save a lot of costs.
Finally, unions are generally used in kitchens and bathrooms because they need to be connected to kitchen and bathroom equipment, which are all threaded.
Extended information
It is understood that most of the heating pipe materials on the market are PPR and PB. PPR, also known as random polypropylene, has good toughness and high strength. PB tube is a high molecular inert polymer with good temperature resistance, durability, chemical stability and plasticity, and long service life.
These two materials have good low-temperature and high-temperature resistance, and can also be hot-melt welded. But in terms of price, PPR pipes and fittings are much cheaper than PB pipe fittings, so PPR pipes are the first choice for heating pipes.
Industry insiders suggest that if your home is going to lay floor heating, metal pipes should be used for exposed pipes exposed on the ground, which will not expand and deform when exposed to heat; if they are concealed pipes, it is recommended to use PPR hot water pipes. This kind of pipe has strong impact resistance, slightly lower melting temperature and good stability.