Press the pressure gauge in front of the Qinghai electric ventilation butterfly valve or press it back? The third way to choose correctly: pay attention to the price. To buy any product, you need to check the price of the product first. This is also one of the important links. If we buy some brand products, the price of the products is generally high, but generally speaking, there will not be a high price. If you want to buy in batches, its price will have a certain discount.
、 2. Fixed ball. The ball is fixed. The ball is pressed against the seal ring through the movement of the bearing, thus forming a sealing function.
