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Jiangsu Ruiling Automation Instrument Co., Ltd

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Jinhu Economic Development Zone, Huai'an City, Jiangsu Province, China

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Welded orifice flowmeter

NegotiableUpdate on 07/01

Model

Nature of the Manufacturer: Producers

Product Category

Place of Origin

Online Consult

Overview

Welded orifice plate flowmeter, corner pressure tapping orifice plate flowmeter, ring chamber pressure tapping orifice plate flowmeter, flange pressure tapping orifice plate flowmeter, throttling orifice plate flowmeter, flow limiting orifice plate flowmeter, high accuracy, easy installation, suitable for large and small diameters, made of C carbon steel and P stainless steel materials

Product Details

1、 Product Overview

RLHW seriesWelded orifice flowmeterIt is a high range ratio differential pressure flow device composed of a standard orifice plate and a multi parameter differential pressure transmitter (or differential pressure transmitter, temperature transmitter, and pressure transmitter), which can measure gas, steam, liquid, and induced flow rates. It is widely used in process control and measurement in the fields of petroleum, chemical, metallurgy, power, heating, water supply, etc. The throttling device, also known as the differential pressure flowmeter, consists of a primary detection element (throttling element) and a secondary device (differential pressure transmitter and flow display instrument), which are widely used in gas applications. Flow measurement of steam and liquid. Featuring a simple structure, easy maintenance, and stable performance

2、 Working principle

The principle of measuring flow rate with a throttling device is based on the famous Bernoulli fluid dynamics principle. Placing a throttling element in the pipeline, when fluid flows through the throttling element, a pressure difference (differential pressure P) will be generated on both sides of the throttling element, and the flow rate at this time is proportional to the square root of the differential pressure.

3、 Purpose, characteristics, and scope of application

1. Purpose: The throttling differential pressure flowmeter consists of three parts: throttling device, differential pressure transmitter, and flow accumulator. The throttling device is a primary element directly installed on the pipeline, and the differential pressure transmitter and integrator are secondary elements. It is mainly used for the flow of various gases (pure or dusty), steam (saturated or superheated), and liquids (conductive or non-conductive; highly corrosive; viscous or containing tiny particles of dirt) through pipelines. It can directly measure volumetric flow rate or mass flow rate.

2. The usage conditions, characteristics, and scope of application of differential pressure flowmeter (standard orifice plate)

a、 Usage conditions:

1. In the measurement section, the fluid must fill the circular tube and continuously flow through the throttling device;

2. The fluid must be a homogeneous single-phase fluid both physically and thermodynamically;

3. The fluid measured by the throttling device must be a stable flow, or can be regarded as a stable slowly changing fluid, and is not suitable for pulsating flow and critical flow measurement;

b、 Characteristics and scope of application:

1. The standard throttling device does not require real flow calibration to ensure its measurement accuracy. (Unique among all flow meters);

2. It is widely applicable to the measured medium and can be used for flow measurement of almost all gases, vapors, and liquids;

3. Applicable diameter ratio β is 0.22-0.75, Reynolds number ReD ≥ 5000, pipeline diameter DN50~1000mm, allowing extrapolation to 5000mm. β=d/D, d - orifice plate opening diameter; D - Actual inner diameter of pipeline

4. The pressure can reach up to 32MPa and can also be used for negative pressure;

5. Medium temperature range: -30 ℃ to+650 ℃;

6. The intelligent differential pressure flowmeter adopts an intelligent differential pressure transmitter, which can set the differential pressure value (within the specified range) on site through buttons or communication methods according to the changes in the flow rate of the measured object, thereby changing the flow range and greatly expanding the system flow range;

7. No movable parts, the mechanism is safe and reliable, easy to use and operate, easy to master, and maintenance free;

According to the national standard GB/T2624-93 of the People's Republic of China and the international standard ISO5167-1, the flow range ratio applicable to throttling devices is 3 (i.e. the ratio of maximum and minimum applicable flow rates). In some cases, a range ratio of 4 is allowed. If the range ratio is greater than the above value, the measurement error at low flow rates using the same differential pressure meter will be significant.

4、 Classification and structural diagram

1. Classification

① Classified by flange clamping method
1. Welding type 2, flange clamping type

② Classified by pressure collection method

1. Corner drilling for pressure measurement; 2. Pressure measurement for corner joint chamber 3 and flange pressure measurement; 4. Radial pressure measurement;

2. Structure and schematic diagram

① Figure 1 Structure diagram of standard annular orifice plate throttling device

1. Flange 2, pressure pipe 3, front ring chamber 4, throttling element 5, rear ring chamber 6, sealing gasket 7, bolt 8, nut

Figure 1 Structural diagram of standard annular chamber orifice plate

5、 Structure and schematic diagram

1、 Various standard orifice plate structures, as shown in Figure 2

Figure 2

6、 Product selection

model	Type spectrum description
RL	enterprise standard
	LG	Flow throttling device
		code	Pressure collection method
		H	Pressure measurement of corner joint chamber
		Z	Corner drilling for pressure measurement
		F	flange taps
		J	Radial pressure measurement
			code	Description of throttling device
			K	standard orifice plate
				code	nominal pressure
				-0.6	0.6
				-1	1
				-1.6	1.6
				-2.5	2.5
					code	Nominal diameter
					DN10	DN10~DN50 (threaded, flange)
					DN50	DN50~DN800 (flange)
						code	flange material
						C	carbon steel
						P	stainless steel
						H	alloy steel
							code	medium
							1	liquid
							2	gas
							3	steam
								code	attachment
								N	Excluding attachments
								F	Equipped with three valve groups, etc
								I	Equipped with F and transmitter (accessories can be selected according to the medium and requirements)
								DC	Equipped with F and multi parameter transmitter
								O	User specified configuration attachments

7、 Installation and usage precautions

1. Approved parameters: Before installation, it is necessary to verify the on-site operating conditions and confirm that all parameters in the throttling device calculation sheet are exactly the same as the operating conditions at the installation point. Otherwise, necessary corrections or compensations must be made.

2. Direction: There are "+" and "-" marks on the handle of the orifice plate or the outer surface of the flange of the throttling device, respectively. "+" represents the upstream side (facing the direction of the fluid) and must not be installed in reverse.

3. Insertion depth: The pressure tapping hole plate in the ring chamber is inserted at a depth of 2-5mm between the pipeline and the ring chamber, but the pipeline cannot be pushed into the ring chamber, otherwise the pipeline will expand due to heat and damage the ring chamber. Drill a pressure tapping hole plate, and the pipeline protruding into the hole plate must not block the pressure tapping hole at any point.

4. System blowing: After the installation of the throttling device is completed, it should be blown. At this time, the throttling element (orifice plate) should be removed first to prevent debris in the pipeline from scratching the orifice plate or blocking the pressure pipe. After the blowing is completed, it should be installed in the same direction as the arrow on the orifice plate and the direction of fluid flow. Pay attention to tightening to ensure sealing.

5. Zero adjustment: After the purging and installation are completed, open the middle valve of the three valve group. At this time, the differential pressure value should be zero. If it is not, it must be reset to zero. The method is to hold down the button in the lower left corner for 20 seconds and release it.

6. Finally, slowly close the middle valve of the three valve group (it must be tightly closed), open all the shut-off valves on the upper part of the positive and negative pressure pipes, and the orifice plate can work normally.

7. Installation coaxiality requirements: The throttling element and the pipeline must be concentric, with an eccentricity distance of no more than 0.0025D. Users should pay attention to or take necessary measures during welding operations.

8. Orifice plates are generally used in conjunction with differential pressure transmitters. When connecting the pressure conduit to the differential pressure transmitter, attention should be paid to not installing the positive and negative pressures in reverse, with "H" indicating positive and "L" indicating negative;

9. The pressure pipes led out from the positive and negative pressure ports must be kept parallel in any situation;

10. If a regulating valve must be installed, it is recommended to install the regulating valve after the required length of the straight pipe section on the downstream calculation sheet.

11. When the measured medium is gas or steam and there are significant fluctuations in temperature and/or pressure, temperature and/or pressure compensation should be performed. The pressure transmitter is installed at 1D upstream, and the thermocouple is installed at 1D downstream.

12. There should be no bag shaped space on the differential pressure signal pipeline where liquid or gas may accumulate. If unavoidable, a gas collector (or exhaust valve) and a settling device (or drain) should be installed.

13. Zero drift of the transmitter can also cause measurement errors, and the differential pressure transmitter should be calibrated regularly during use.

14. In addition to regularly inspecting the pressure pipes to prevent blockage, outdoor pressure pipes should be properly insulated to prevent solidification or freezing. If the pipeline (vertical section) is quite long, false pressure difference caused by temperature difference should be avoided. At this time, it is recommended to lay two differential pressure pipelines close to each other and wrap them together in the insulation layer.

15. Differential pressure pipelines should have brackets to prevent vibration and strong forces from acting on the differential pressure gauge.

16. When hoisting the throttling device on site, it is strictly prohibited to use iron wire, steel wire, or hook to penetrate the throat hole of the throttling element to prevent sharp mouth damage and affect accuracy;

17. After using the throttling device for a period of time, due to the presence of solid particles in the liquid and liquid droplets or other impurities in the gas, the sharp inlet will be blunted, resulting in an increase in the outflow coefficient and additional errors. At this time, it is necessary to consider replacing the throttling element; In addition, after long-term use, the throttling device is prone to accumulate dirt at the lower corner of the upstream side of the orifice plate, which can cause changes in the outflow coefficient. Therefore, regular inspections should be carried out to eliminate dirt.

18. Pressure tube: The material of the pressure tube should be determined according to the properties and parameters of the measured medium. If the inner diameter is too small or the length is too long, it will cause serious signal lag or distortion. It is recommended to refer to Table (1) for determination.

Table 1: Inner Diameter and Length of Pressure Pipe

19. Selection of installation locations for different media:

The gas pressure tapping port is preferably located at the upper part of the pipeline; The liquid pressure tapping port should be located below the side, but not directly below, as sediment particles may block the pressure tapping port; The pressure tap for steam is located on the side of the pipeline; As shown in the following figure:

1、 Installation requirements on horizontal pipelines

1. As shown in Figures 4 and 5: When measuring the flow rate of liquid and water vapor media, the optimal installation angles for the pressure tapping tube are 0 ° and 180 °; If installation is not possible at 0 ° and 180 °, it can be selected within the range of 0 ° to 60 ° and 120 ° to 180 °. But the differential pressure transmitter must be installed vertically on the vertical end face of the three valve group.

2. As shown in Figure 6: When measuring the flow rate of gas medium, the optimal installation angle for the pressure tapping tube is 270 °. If it is impossible to install at 270 °, it can be installed within the range of 210 ° -270 ° and 270 ° -330 °. But the differential pressure transmitter must be installed horizontally on the top horizontal plane of the three valve group.

2、 Installation requirements on vertical pipelines

1. As shown in Figure 7, when measuring the flow rate of water vapor and liquid media, the differential pressure transmitter is installed on one side of the pressure tap at the lower end of the vertical pipeline, and vertically installed on the vertical end face of the three valve group plate below the pressure tap.

2. As shown in Figure 8, when measuring the flow rate of gas medium, the differential pressure transmitter is installed on one side of the high-end pressure tap of the vertical pipeline, and horizontally installed on the horizontal end face of the three valve group plate higher than the pressure tap.

8、 Integrated throttling device

The integrated throttling device is assembled by the flowmeter manufacturer according to the user's requirements, including the throttling device, globe valve, condenser (or condensing ring), impulse pipe, three valve group, and differential pressure transmitter. Simply weld the flange to the pipeline and connect it to the differential pressure transmitter cable upon arrival to put it into use. The schematic diagram of its structure and composition is shown in Figure 9.

Figure 9

9、 Ordering Notice:

1. After installing the orifice plate flowmeter with throttling components, it is necessary to confirm that there are flammable and explosive materials in the surrounding environment. If there are, please choose an explosion-proof flowmeter.

2. The pressure measurement methods for orifice flow meters with throttling components are indicated as follows: flange pressure measurement, corner pressure measurement, radial pressure measurement

3. When the purchase quantity is large, a company technician should be sent to our company to have a face-to-face meeting with our technical personnel, so that the selection of instrument parameters will not be wrong.

4. Please specify the model, nominal diameter, nominal pressure, working medium, working pressure, medium temperature, medium density, flow range, and pipeline material when placing an order.

Related products:

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Orifice flowmeter with throttling element