PD flow meter-spiral double rotor is the latest generation of positive displacement flow meter, a precision instrument used for the measurement and control of liquid flow in pipelines. It adopts a pair of special toothed spiral rotors. No pulsation, extremely low noise, high precision, high reliability, large flow rate, and strong environmental adaptability.
The flow meter is equipped with a pointer and a wheel counter, which can indicate the accumulated amount of flow. The counter with a zero device can also indicate a single accumulation. It can also output electrical pulse signals and 4-20mA analog output.
Repeatability error: The repeatability error of the flow meter does not exceed 1/3 of the absolute value of the basic error limit of the flow meter.
Operating medium temperature: ambient temperature (-41℃~+50℃); Level 0.5 (-20℃~+80℃) ;Level 0.2(-20℃~+60℃); with high temperature radiator up to 250℃
2. Flow Range
Table 1, accuracy level 0.5
Model
Diameter
Viscosity mPa.s
0.3~0.8
0.8~2
2~15
15~400
400~1000
1000~2000
2000~3500
Gasoline
Kerosene
Diesel, engine oil
Heavy oil
High viscosity liquid
LLT-0252
25
3~9
1.5~10
1~10
1~10
1~8
1~8
1~6
LLT-0401
40
3~9
1.5~10
1~10
1~10
1~8
1~8
1~6
LLT-0402
7~20
3~22
2.5~25
2.5~25
2~18
2~18
3~12
LLT-0501
50
7~20
3~22
2.5~25
2.5~25
2~18
2~18
3~12
LLT-0502
9~36
4.5~36
3.6~36
3.6~36
2.8~25
2.8~25
4.5~18
LLT-0801
80
9~36
4.5~36
3.6~36
3.6~36
2.8~25
2.8~25
4.5~18
LLT-0802
20~80
10~80
10~100
10~100
6.5~56
6.5~56
5~40
LLT-1001
100
20~80
10~80
10~100
10~100
6.5~56
6.5~56
5~40
LLT-1002
25~100
18~100
15~150
15~150
8.5~80
8.5~80
6.5~55
LLT-1501
150
25~100
18~100
15~150
15~150
8.5~80
8.5~80
6.5~55
LLT-1502
55~225
30~250
25~250
25~250
18~150
18~150
10~100
LLT-2001
200
55~225
30~250
25~250
25~250
18~150
18~150
10~100
LLT-2002
90~360
50~400
40~400
40~400
28~240
28~240
20~160
LLT-2501
250
90~360
50~400
40~400
40~400
28~240
28~240
20~160
LLT-2502
130~540
65~540
60~600
60~600
42~360
42~360
30~240
LLT-3001
300
130~540
65~540
60~600
60~600
42~360
42~360
30~240
LLT-3002
220~800
110~900
95~950
95~950
70~600
70~600
54~450
LLT-3501
350
220~800
110~900
95~950
95~950
70~600
70~600
54~450
Table 2, accuracy level 0.2
Model
Diameter
Viscosity mPa.s
0.3~0.8
0.8~2
2~15
15~400
400~1000
1000~2000
2000~3500
Gasoline
Kerosene
Diesel, engine oil
Heavy oil
High viscosity liquid
LLT-0252
25
3.5~8
3~10
2~10
2~10
2~8
2~8
2~6
LLT-0401
40
3.5~8
3~10
2~10
2~10
2~8
2~8
2~6
LLT-0402
8~20
5.5~22
4.5~22
4.5~22
4~18
4~18
3~12
LLT-0501
50
8~20
5.5~22
4.5~22
4.5~22
4~18
4~18
3~12
LLT-0502
15~36
9~36
7~36
7~36
6~25
6~25
4.5~18
LLT-0801
80
15~36
9~36
7~36
7~36
6~25
6~25
4.5~18
LLT-0802
30~80
20~80
15~80
15~80
14~56
14~56
10~40
LLT-1001
100
30~80
20~80
15~80
15~80
14~56
14~56
10~40
LLT-1002
40~100
25~100
20~120
20~120
18~72
18~72
14~55
LLT-1501
150
40~100
25~100
20~120
20~120
18~72
18~72
14~55
LLT-1502
88~220
57~225
44~220
44~220
38~150
38~150
25~100
LLT-2001
200
88~220
57~225
44~220
44~220
38~150
38~150
25~100
LLT-2002
150~360
90~360
72~360
72~360
50~210
50~210
40~160
LLT-2501
250
150~360
90~360
72~360
72~360
50~210
50~210
40~160
LLT-2502
180~540
135~540
100~540
100~540
90~360
90~360
60~240
LLT-3001
300
180~540
135~540
100~540
100~540
90~360
90~360
60~240
LLT-3002
250~800
220~900
180~900
180~900
150~600
150~600
110~450
LLT-3501
350
250~800
220~900
180~900
180~900
150~600
150~600
110~450
Remarks: Class 0.3 and Class 0.1 flowmeters can be provided upon special request.
How does a PD flow meter work?
The PD flow meter is mainly composed of a main body, a pair of spiral rotors, a magnetic coupling, a reduction mechanism, an adjustment gear, a counter and a signaling device.
It is a volumetric flowmeter. It uses the hollow part of the spiral rotor (measuring element) and the inner wall of the metering box to form a closed cavity (see the shaded part in the figure) as the measurement chamber.
The small pressure difference between the inlet and outlet drives the rotor to rotate. At the same time, although each rotor receives different rotational moments from the fluid on the same cross-section, the resultant torque of the two rotors receiving rotational moments on all cross-sections is equal.
Therefore, the two rotors each rotate at the same speed and torque, and the displacement is balanced and pulsation-free. The spiral rotor can output 8 times the volume of the cavity per revolution.
Therefore, the rotation speed of the rotor is proportional to the cumulative flow rate of the fluid, and the rotation speed of the rotor is proportional to the instantaneous flow rate of the fluid. The number of revolutions of the rotor is transmitted to the meter counter through the magnetic coupling, which displays the flow rate flowing through the flow meter (flowing through the pipe).
Featured Applications
PD flow meter is a precision instrument used for measurement and control of liquid flow in pipelines.
PD Flow meters can be made of different materials and are widely used in petroleum, chemical industry, light industry, commerce, scientific research and other departments. It is especially suitable for measuring industrial liquids such as crude oil, refined oil, and light hydrocarbons.
Ship application:
The maximum displacement of the spiral double rotor flowmeter can reach 980 cubic meters/hour (customized), and it is equipped with the same filter to meet the needs of ships.
PD meter is a positive displacement flow meter. orifice meter is a differential pressure flow meter.
First, they work differently.
When the fluid passes through the PD meter, a certain pressure difference will be generated between the inlet and outlet of the flow meter. The rotating part of the flow meter (referred to as the rotor) rotates under the action of this pressure difference and discharges the fluid from the inlet to the outlet. In this process, the fluid fills the “metering space” of the flow meter again and again. Then they are sent to the exit continuously. Under given flow meter conditions, the volume of this metering space is determined. Just measure the number of rotations of the rotor. The cumulative value of the fluid volume passing through the flow meter can be obtained.
The working principle of the orifice plate meter: When the fluid fills the pipe and flows through the throttling device in the pipe, the flow stream will shrink locally, thereby increasing the flow rate and reducing the static pressure. As a result, a pressure drop occurs before and after the throttling device, that is, the pressure Difference. The greater the flow rate of the medium flowing, the greater the pressure difference generated before and after the throttling member. Therefore, the orifice flowmeter can measure the fluid flow rate by measuring the pressure difference. This measurement method is based on the law of energy conservation and the law of flow continuity.
Secondly, the main reason is that their measurable media are different. The orifice flowmeter has a wide range of applications. It can measure all single-phase flows (gas, liquid, steam) and some mixed-phase flows. PD meter is mainly used to measure liquids. Oil measurement applications are mostly used. Can be used for measuring high viscosity liquids.
First of all, each pair of wheels of the oval gear is a driving wheel and a driven wheel. One wheel drives the other wheel. Collision and friction will inevitably occur, which will affect the service life. And as the use time increases, the accuracy will be affected. Impact. The two rotors of the double rotor are both driving wheels, which overcomes this shortcoming of the oval gear flowmeter.
Secondly, the two rotors of the double rotor are meshed point by point. There is no noise, no friction during use, and no wear and tear with extended use time. This ensures its service life and measurement accuracy, and reduces amount of maintenance.
The double-rotor flowmeter has only two clearance surfaces, while the oval gear flowmeter has 8 clearance surfaces (taking two wheels as an example). When measuring low-viscosity media, the accuracy of the two is different when measuring the same viscosity media. It is different, the double rotor is taller than the oval gear.
The pulsation of the oval gear flowmeter is relatively large, while the dual-rotor one is smooth. This is determined by the measurement principle mentioned in Article 1.
From a technical point of view, double rotor flowmeters, as an alternative to elliptical gears (including elliptical gears), are being used in more and more process devices that require high reliability, and have received favorable reviews.
In terms of price, there is little difference between the two, especially when the diameter is larger and the material is stainless steel. Even the oval gear is more expensive than the double rotor.
Compared with elliptical gears, the twin rotors are much smaller and easier to install and maintain.
Compared with elliptical gears, the double rotor has good viscosity adaptability (especially suitable for chemical media).
More Featured liquid flow meters
SI-3601 Positive Displacement Oval Gear Fuel Flow Meter
PD Flow Meter-Spiral Double Rotor is a precision instrument used for the measurement and control of liquid flow in pipelines. It is a new generation of volumetric flowmeter manufactured by our company. Because it uses a pair of special toothed spiral rotors, it is also called “spiral double rotor flowmeter”.
PD Flow Meter-Spiral Double Rotor has the remarkable characteristics of no pulsation, extremely low noise, high precision, high reliability, large flow rate, and strong environmental adaptability. The double-rotor flowmeter launched by Sino-Inst supports the output of electrical pulse signals and flow analog 4~20mA signals for remote instantaneous flow indication or flow adjustment and control. It is widely used in commercial trade measurement and engineering management control in petrochemical, metallurgy, electronics, terminals and other departments.
If you need to purchase PD Flow Meter-Spiral Double Rotor, or have related technical questions, please feel free to contact us.
Zhang Wei, possesses 20 years of experience as an automation instrumentation engineer, specializing in the research, design, installation, commissioning, and maintenance of automation instruments.
Face to various instrument communication protocols (such as Modbus, Profibus, etc.), with solid hardware circuit design and software programming skills (proficient in C language and PLC programming). Has extensive project experience; projects he has led and participated in have all achieved outstanding results, improving product accuracy, reducing costs, and increasing production efficiency.
Possesses excellent communication and coordination skills and a strong team spirit, enabling him to quickly respond to customer needs and provide high-quality automation instrumentation solutions.
PD Flow Meter-Spiral Double Rotor for Crude Oil, Heavy Oil, Ship Trade Measurement
PD flow meter-spiral double rotor is the latest generation of positive displacement flow meter, a precision instrument used for the measurement and control of liquid flow in pipelines. It adopts a pair of special toothed spiral rotors. No pulsation, extremely low noise, high precision, high reliability, large flow rate, and strong environmental adaptability.
