TIDM-ULTRASONIC-WATER-FLOW-MEASUREMENT: molding material and reflector material for flow meter transducers

Hello Rashmi,
this is a difficult question, as our own reference design is based on the intrusive placement of the transducers in the pipe. I will check, whether the experts on our side can make some recommendations. We'll come back to you as soon as possible.

Best regards
Peter

Hello Peter Spevak,

                                i have read that we can do flow meter non intrusively so i am trying non intrusive type am i doing wrong ....? can't i get done it non intrusively..?

and i do need help in calculation part please do suggest me mounting type material used to make molding and how do i calculate the flow rate for 45degree angle placement of transducer....?

Regards,

Rashmi H M

Hi Rashmi,

The material used between the transducers and the pipe should be similar in mechanical properties to the pipe itself if possible. For example, if you are sensing through a PVC pipe, something which is similar to PVC in material properties is desirable.Tranducer manufacturers can make a recommendation on the material(or may even be able to provide their transducers with common interface materials). Can you tell me what the pipe is made out of and what the thickness and diameter of the pipe is?

BR,
Leo

Hello Leo,

                i am using UPVC pipe for my flow meter application, I contacted the Transducer manufacture in Audio-well but it was not much Help because i need to make mold ready locally so If you suggest materials i can try it locally so please do help me Leo.

Pipe material = UPVC

Diameter 1.8 cm

Thickness 0.2mm to 0.3mm

I am trying to mount the transducer in 45 degree angle non intrusively

Regards,

Rashmi H M

Hi Rahmi,

I've spoken with another transducer manufuacturer in China(JIaKang). They are using PEEK and acrylic for injection molding of their transducer mount to PVC pipe. You will also need to have some coupling compound between the pipe/mount and mount/transducer interface.  They recommended a 1MHz transducer for this and have verified that it can work with 3V excitation.  The material and sensitivity of the transducer are also important since there are three interfaces you need to consider for signal loss(the transducer mount interface, the mount pipe interface, and the pipe water interface).

Since you are mounting at 45 degrees, you'll get half the change in time of flight that you would for a U-pipe design over the same propagation distance. (The u-pipe design uses reflectors to propagate the ultrasonic wave in parallel to the flow.)  The best approach is usually to calibrate flow through a pipe with your ultrasonic system using a known reference(another water meter). Let me know if this answers your questions.

BR,
Leo

Hello Leo,
Thanks for the reply,and what would be the coupling compound that i can use ....?
I din't get what is U-pipe design can you please tell me or add a pic How U-pipe design or mount looks like...?
I tried 45degree mounting type but am not able to receive proper echo so,i want to try 45degree mounting with proper molding of transducer,sp please suggest me what is U-pipe design and the coupling compound material type..?

Regards,
Rashmi H M

Hi Rashmi,

There are a number of different ultrasonic couplants available depending on the requirements of your application. You might contact Olympus(that sells ultrasonic couplants). A u-pipe design is intrusive and is commonly used in intrusive flow meters.

BR,

Leo

Hello Leo,
Thanks for the information and to use u type pipe we don't want to do intrusive type we are trying non intrusive type.

What type materials can be used to reflector because i have used aluminium plate as reflector but its not working so please guide me to choose reflector material..?

Regards,
Rashmi H M

Hi Rashmi,

The reflective material in a non-intrusive clamp on water meter is the material of the pipe itself. If you're pipe is PVC, it's PVC.  I don't know what the best material would be in an intrusive u-pipe design. From the DN-20 pipe I have here, it looks like the reflector is made of aluminum, but the face of the reflector has a different metal coating on it. If I had to guess, I would guess this is some polished/electro-plated steel alloy which is resistant to lime build up.  You can get a DN-20 brass pipe from various water transducer manufacturers and use it with our solution.  I assume from your previous posts that you are pursuing a non-intrusive solution - if so there isn't a dedicated reflector.

BR,
Leo

Hello Leo,

                 Thanks for the information Leo,I tried pipe material as reflector but it is not working for non intrusive,i will try aluminium with coating material....

Regards,

Rashmi H M