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Your Distributor
Bronkhorst USA Inc57 So. Commerce Way Suite 120
PA 18017 Bethlehem
USA
T: +1 610 866 6750
F: +1 610 866 9212
sales@bronkhorstusa.com
Live help
Mass Flow ONLINE delivers high quality flow meters and flow control instruments of Bronkhorst High-Tech B.V. and partners, not requiring customer specific advice or a quotation.
All prices are available online.
Some products have a quantity discount. If there is, it's displayed on the product page in the shop.
After putting the right amount of meters (and accessories) in the shopping cart, the shipment price will be displayed under the shopping cart. Please select your country and press update to see the price for your country, based on the weight and volume of the shopping cart contents.
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As soon as the order is placed, an order acknowledgement is dent to you.
Please check this acknowledgment thouroughly to prevent failures or misunderstandings. The order will be despatched upon arrival of the payment.
If you need a proforma invoice for the payment, please login, select My Account and select the order.Here you can print the proforma invoice.
When the orders have been picked up but the carrier, the invoice can be printed using the same way.
We only have the electronic invoice, an invoice on paper will not be sent seperately.
The kinematic viscosity [m2/s] is the ratio between the dynamic viscosity [Pa.s = 1 kg/m·s] and the density of a fluid [kg/m3].
The SI unit of the kinematic viscosity is m2/s.
Other units are:
1 St (Stoke) = 1 cm2/s = 10−4 m2/s.
1 cSt (centiStoke) = 1 mm2/s = 10−6m2/s.
Water at 20 °C has a kinematic viscosity of about 1 cSt.
This video shows the order process at Mass Flow ONLINE. (video length 4 minutes)
Mass Flow ONLINE offers several payment methods.
For customers who are able to purchase and pay at the same time we offer the following real time payment methods:
- Verified by VISA
- Mastercard® SecureCode™
- American Express
- PayPal
- iDEAL (only in The Netherlands)
For customers who have seperate purchase and payment processes, we offer an alternative:
- Wire transfer
- Bank transfer
- T/T transfer
- Money transfer
First you start the purchase process, select wire payment (bank transfer), and finalize the purchase process. The status of your order is Waiting for payment. You will receive an order acknowledgement within a minute. In this order acknowledgement, all our bank details are specified (bank account number, bank name and address, Swift Code, BIC).
This order confirmation contains a link to a detailed invoice, enabling your finance payment department to arrange pre-payment. When payment is received, the status of your order is updated to Paid. You will be notified by e-mail.
It is common to identify pipes by inches using NPS or "Nominal Pipe Size". NPS is often incorrectly called National Pipe Size, due to confusion with national pipe thread (NPT). The metric equivalent is called DN or "diametre nominel". The metric designations conform to International Standards Organization (ISO) usage and apply to all plumbing, natural gas, heating oil, and miscellaneous piping used in buildings. The use of NPS does not conform to American Standard pipe designations where the term NPS means "National Pipe Thread Straight". Based on the NPS and schedule of a pipe, the pipe outside diameter (OD) and wall thickness can be obtained from reference tables such as those below, which are based on ASME standards B36.10M and B36.19M.
Diameter Nominal DN (mm) |
Nominal Pipe Size NPS (inches) |
Outside diameter (OD) inches (mm) |
| 6 | ⅛ | 0.405 in (10.29 mm) |
| 8 | ¼ | 0.540 in (13.72 mm) |
| 10 | ⅜ | 0.675 in (17.15 mm) |
| 15 | ½ | 0.840 in (21.34 mm) |
| 20 | ¾ | 1.050 in (26.67 mm) |
| 25 | 1 | 1.315 in (33.40 mm) |
| 32 | 1¼ | 1.660 in (42.16 mm) |
| 40 | 1½ | 1.900 in (48.26 mm) |
| 50 | 2 | 2.375 in (60.33 mm) |
| 65 | 2½ | 2.875 in (73.02 mm) |
| 80 | 3 | 3.500 in (88.90 mm) |
| 100 | 4 | 4.500 in (114.30 mm) |
| 150 | 6 | 6.625 in (168.27 mm) |
| 200 | 8 | 8.625 in (219.08 mm) |
| 250 | 10 | 10.75 in (273.05 mm) |
If you ordered the wrong article, please read the exchange procedure on our website and act as soon as possible.
Mass flow should actually be expressed in units of weight such as g/h, mg/s, etc. Most users, however, think and work in units of volume. No problem, provided conditions are agreed upon, under which the mass is converted to volume.
Our STP or standard temperature and pressure conditions used are stated here:
Normal conditions (ln/min): a temperature of 0 °C (or 32°F) and a pressure of 1.013 bar (or 14.69 psi) are selected, and these reference conditions are indicated by the underlying letter "n" in the unit of volume used. The direct thermal mass flow measurement method is always based on these reference conditions unless otherwise requested.
Standard conditions (ls/min): here the reference conditions are based on 20 °C (68°F) instead of 0 °C (32°F). Please be aware of this difference, because mixing up these reference conditions causes an error of 7%!
Typical flow unit |
Reference conditions for gas temperature |
Reference conditions for gas pressure |
|
mln/min |
0 °C / 32 °F |
1.013 bar / 1 atm / 14.69 psi |
|
ln/min |
0 °C / 32 °F |
1.013 bar / 1 atm / 14.69 psi |
|
sccm |
0 °C / 32 °F |
1.013 bar / 1 atm / 14.69 psi |
|
slm |
0 °C / 32 °F |
1.013 bar / 1 atm / 14.69 psi |
|
mls/min |
20 °C / 68 °F |
1.013 bar / 1 atm / 14.69 psi |
|
ls/min |
20 °C / 68 °F |
1.013 bar / 1 atm / 14.69 psi |
Our average delivery time is 48 working hours.
This means when the order is placed and paid, the order will be despatched within 48 working hours. The status of your order can be tracked in your account.
Please check the availability which is displayed at every product page. You will be warned when there is insufficient stock which can lead to a delay in the delivery.


