Welcome to the world of inches, millimeters, and DN dimensions
On our website, you will encounter various measurements, which can be confusing if you do not work daily with pumps, hoses, and accessories. With the explanations below, we try to guide you so that you can easily find the right materials on our site. If you still have questions: call us!!
Threaded connections
Threaded connections are indicated in BSP measurements and expressed in inches. Professionals often use the term "inches." It would have been very easy if the mentioned inches could be measured directly with your tape measure, but unfortunately, that is not the case. The overview below is based on the outer diameter of the thread.
| 1/4" | = | 13.72mm |
| 3/8" | = | 17.15mm |
| 1/2" | = | 21.34mm |
| 3/4" | = | 26.67mm |
| 1" | = | 33.40mm |
| 1 1/4" | = | 42.16mm |
| 1 1/2" | = | 48.26mm |
| 2" | = | 60.30mm |
| 2 1/2" | = | 73.02mm |
| 3" | = | 88.90mm |
| 4" | = | 112.97mm |
(The above is a good approximation)
If you measure an internal threaded connection, it will be smaller. Keep this in mind!
Hoses
To determine the correct hose size, we measure the inner diameter. This inner diameter is often given in inches, and fortunately, you can refer to your tape measure in inches for this.
| 12.5mm | = | 1/2" |
| 15mm | = | 5/8" |
| 19mm | = | 3/4" |
| 25mm | = | 1" |
| 32mm | = | 1 1/4" |
| 38mm | = | 1 1/2" |
| 50mm | = | 2" |
| 63mm | = | 2 1/2" |
| 75mm | = | 3" |
| 100mm | = | 4" |
(Different sizes may apply!)
For hose tails, we usually indicate the size in inches, except if the tail has threads. For threaded hose tails, the tail is given in millimeters and the thread in inches. So, if you need a hose tail for a pump with a 1" female thread and a hose with 25mm inner diameter, you will need a male threaded hose tail with dimensions: 1" x 25mm.
Pressure pipes
Unlike hoses, for pressure pipes we measure the outer diameter, which is almost always given in millimeters. However, pressure pipes are sometimes also referred to in inches, looking at the inner diameter. A PVC pipe with a 32mm outer diameter is thus called “1 inch” because after subtracting the wall thickness, the inner diameter is around 25mm.
Flange connections
Some pumps in our range come with flange connections. These are indicated in DN, have a number of bolt holes, and are equipped with female threads. We always supply pumps with flange connection with counter-flange, sealing gasket, and bolts so you can focus on the internal thread connection.
| DN32 | = | 1 1/4" |
| DN40 | = | 1 1/2" |
| DN50 | = | 2" |
| DN65 | = | 2 1/2" |
| DN80 | = | 3" |
| DN100 | = | 4" |
| DN125 | = | 5" |
| DN150 | = | 6" |
We understand that the above information cannot cover all your questions, so if you have any further queries, please contact us!