top of page

常見問題

我們希望能夠幫忙解答閣下的問題

這裡你會找到一些我們經常收到的問題的答案。如果閣下有疑問,請看看下方的列表,你要的答案可能會在那裡。

但如果你找不到你想要的,歡迎隨時聯絡我們

我們希望能夠幫忙。

  • Ductile Iron Pipe
    DN (Diameter Nominal) mm and inch are used often as well Is it true that for DN XX pipe, pipe outer diameter (O.D.) is XXmm? D.I. pipe size is different from pipe O.D. in any size.
  • G.I. / Black Steel Pipe
    DN (Diameter Nominal) mm and inch are used often as well Is it true that for DN XX pipe, pipe outer diameter (O.D.) is XXmm? Not always. For instance, pipe O.D. of DN15 1/2" pipe is not 15mm; while for size DN350 14" and above, size equals to pipe O.D. AMSE standard is for seamless steel pipe and seamless pipe fitting
  • Does outer diameter affect installation?
    No. Outer diameter would not affect bolts going through two flanges, only PCD would. Difference in outer diameter will only affect how it looks.
  • How to choose the right flange?
    To choose the right flange, below information is needed: Pitch Circle Diameter (PCD) Number of Bolt Holes Pipe Size Pitch Circle Diameter (PCD) is the diameter of a circle that goes through all bolt holes. Number of Holes matters. Different flanges can have the same PCD with different number of bolt holes. 
  • Can flanges in different standards be used together?
    Flanges in different standards cannot be used together in most of the sizes. Yet, for some sizes, different standards share the same PCD and number of bolt holes. In this case, they can be used together. Sometimes, people use smaller bolt for flanges with PCD difference less than 5mm to avoid fixing the pipe.
  • Common Scale for Pressure Gauge
    Pressure Gauge 15 PSI = 100 KPA 1 BAR = 1 KG/CM^2 = 100 KPA = 0.1 MPA 50 PSI / 350 KPA / 3.5 KG/CM^2 / 3.5 BAR 100 PSI / 700 KPA / 7 KG/CM^2 / 7 BAR 150 PSI / 1000 KPA / 10 KG/CM^2 / 10 BAR 200 PSI / 1500 (1600) KPA / 15 KG/CM^2 / 15 BAR 300 PSI / 2000 KPA / 20 KG/CM^2 / 20 BAR
  • Delivery to Macau
    We can arrange delivery with: ​Hong Kong - Macao Shipping Company Courier
  • How much is the amount of purchase for free delivery?
    With total amount exceed HKD $12,000, we will arrange delivery to your designated address on ground floor for free. For remote area and places requires entrance or parking fee, please Contact Us.
  • Local Delivery
    We can arrange delivery with: Our own lorry crane Hiring a van (it will need driver's consent to buy the goods for you) Courier
WhatsApp 海聯五金
bottom of page