Positive Displacement Flow Meter is also called PD Meter. A positive Displacement Flow Meter can directly measure the volume of liquid passing through. The PD Meter achieves this by trapping fluid between rotating parts in a high-precision chamber. This can be compared with repeatedly filling the beaker with liquid and pouring the contents downstream while counting the number of times the beaker has been filled.
The Sanitary Positive Displacement Flow Meter is made of stainless steel and is quickly connected by Tri-clamp. Can be used to measure viscous liquids in the food industry. Such as sweeteners, edible oil, palm oil, honey, fat, tallow, fat, syrup, molasses, etc.
Features of Sanitary Positive Displacement Flow Meter
Specifications of Positive Displacement Flow Meter
|Body Material||Cast iron||Cast Steel||Stainless Steel|
|Signal Output||Optional: Pulse or 4-20mA|
|Power supply||None or None or 24V DC|
|Accuracy||Standard: 0.5%; Optional: 0.2%|
|Installation Method||Flange,Tri clamp-stainless steel|
|Model||Size(mm)||Medium Viscosity (mPa. s)|
Note: when the viscosity is over 200 mPa. S, it belongs to high viscosity medium.
Positive displacement flow meter working principle
In principle, a positive displacement flow meter is a hydraulic engine that absorbs a small amount of energy from a fluid.
This energy is used to overcome the frictional force of the rotation of the flow detection element and the accessories, and at the same time form a pressure drop at the inflow and outflow ends of the meter.
The working principle of a typical Positive displacement flow meter (elliptical gear type) is shown in the figure.
The two OVAL gears have a special shape that rolls over each other for contact rotation.
P1 and p2 represent the inlet pressure and outlet pressure respectively, obviously p1>p2.
Figure 1(a) The lower gear rotates counterclockwise under the pressure difference between both sides, which is the driving wheel;
Because the pressure on both sides of the upper gear is equal, no rotating torque is generated. It is a driven wheel, driven by the lower gear, and rotates in a clockwise direction.
In the position in Figure 1(b), both gears generate a rotational torque under the action of differential pressure and continue to rotate.
When it is selected to the position of Fig. 1(c), the upper gear becomes the driving wheel, and the lower gear becomes the driven wheel, and it continues to rotate to the same position as Fig. 1(a) to complete a cycle.
One cycle action discharges the fluid volume of the four crescent-shaped cavities enclosed by the gear and the shell wall. This volume is called the “circulation volume” of the flowmeter.
Suppose the flow meter’circulation volume’ is υ, and the number of gear rotations in a certain period of time is N. Then the volume of fluid flowing through the flow meter in that time is V,
Then V=Nυ (1)
The rotation of the elliptical gear is transmitted to the counter through the magnetic seal coupling and the transmission reduction mechanism to directly indicate the total amount flowing through the flowmeter. If the sending device is attached, and then equipped with an electric display instrument, the remote transmission can only be instantaneous flow or cumulative flow.
Although there are many segmentation methods to form various forms of PDF, most of them have similar basic characteristics.
The main reason for the PDF error is the leakage of the gap between the movable measuring piece and the static measuring chamber that divides a single fluid volume.
One of the reasons for the leakage is to overcome the frictional resistance of the moving parts; the second is the pressure drop formed by the hydraulic resistance of the instrument.
Read more about: Positive Displacement Flow meter Technology
Positive displacement flow meter advantages and disadvantages
Read more about Mass Flow Rate vs Volumetric Flow Rate
Types of positive displacement flow meter
Positive displacement (PD) flow meters are volumetric flow measurement instruments. They are ideal for low flow rates, high viscosity fluids, and flow measurement involving start and stop or pulses.
Positive displacement flow meters are similar in design to gear pumps. However, the principle of operation is the opposite. It is not the gear that drives the fluid, but the fluid that drives the gear.
The non-intrusive Hall effect sensor detects the movement of the gear. When each gear tooth passes the sensor, a square wave pulse is generated and a discrete volume of liquid is measured. The pulse sequence generated is proportional to the actual flow rate and provides a highly accurate representation of the fluid flow.
There are many styles of positive displacement flow meters, and we provide three of them:
Extended reading: Stainless steel flow meters|304-316 optional
You may like:
Sino-Inst, Manufacturer for Positive Displacement Flow Meters. For example crude oil flow meter, diesel flow meter, gasoline flowmeter.
Sino-Inst’s Positive Displacement Flow Meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, the US, and other countries.
Request a Quote
SS-Tri clamp Sanitary Positive Displacement Flow Meter
Positive Displacement Flow Meter is also called PD Meter. A positive Displacement Flow Meter can directly measure the volume of liquid passing through. The PD Meter achieves this by trapping fluid between rotating parts in a high-precision chamber. This can be compared with repeatedly filling the beaker with liquid and pouring the contents downstream while counting the number of times the beaker has been filled.The Sanitary Positive Displacement Flow Meter is made of stainless steel and is quickly connected by Tri-clamp. Can be used to measure viscous liquids in the food industry. Such as sweeteners, edible oil, palm oil, honey, fat, tallow, fat, syrup, molasses, etc.
Product SKU: Tri clamp-Stainless steel Sanitary Positive Displacement Flow Meter
Product Brand: Sino-Inst
Product Currency: USD
Product Price: 500
Price Valid Until: 2029-09-30
Product In-Stock: PreOrder