STZH Intelligent Integrated Orifice Flow Meter

STZH type intelligent integrated orifice flowmeter

1、 Overview:

The STZH intelligent integrated orifice flow meter is the latest fully functional next-generation integrated orifice flow metering system developed by our company. It comprehensively solves the problems of antifreeze, blockage, heat resistance, pressure balance, and medium isolation that exist in orifice flow meters, and can perform composite measurements of differential pressure, pressure, and temperature according to user needs. It can also achieve online iterative calculation of flow rate according to user requirements, on-site display (can display cumulative and instantaneous flow rate; 17 parameters such as temperature, pressure, differential pressure, medium density, etc.), and output 4-20mA standard signals at the same time. Its integrated, user-friendly, and practical design provides users with a new high-performance flowmeter with high accuracy, convenience, practicality, simple maintenance, and low cost.

2、 Design points and structural description:

1. Structural composition:

The STZH intelligent integrated orifice flowmeter consists of an integral orifice plate (or nozzle, 1/4 round nozzle, etc.), root valve, pressure pipe, heat dissipation device, three valve group, differential pressure transmitter, LCD display, etc.

2. Connection method:

The orifice plate and pressure tapping hole are processed as a whole, and the drilling hole and orifice plate form an integral orifice plate at a horizontal angle of 30 ° to 45 °. Two valves are aligned with the axis of the pressure tapping hole and welded to the positive and negative pressure tapping ports of the orifice plate through stainless steel short pipes. The root valve is connected to the heat dissipation device through a pressure guiding pipe (which has a drainage hole and a liquid injection hole), and then connected to the three valve group through a pressure guiding short pipe and a joint. The three valve group is connected to the orifice plate through a pillar, and the other side of the three valve group is connected to the differential pressure transmitter and the pressure transmitter chamber (can be independently equipped with pressure and temperature transmitters), achieving the measurement of differential pressure, pressure, and temperature. When working under special conditions, it can be processed into welded or flanged orifice plates as needed

3. Design points:

3.1 Detachability and Inspection Capability: The root valve can solve the problems of transmitter disassembly and pressure pipe blockage. Closing the root valve can cut off the passage between the measurement system and the pipeline, making it easy to disassemble and assemble components such as the three valve group and differential pressure transmitter. Closing the three valve group can cut off the connection between the pipeline and the differential pressure transmitter. If the pressure tapping hole of the orifice plate or the root valve is blocked, it can be pressurized and blown through the water injection hole of the heat dissipation device. You can also open the drainage outlet of the heat dissipation device for drainage (after drainage, the liquid should be refilled), the liquid injection hole of the heat dissipation device, and if necessary, check the blockage of the root valve

3.2. Anti unidirectional pressure impact: The three valve group can be opened by the middle valve to avoid single item impact on the differential pressure transmitter when opening and closing pipeline valves during operation.

3.3 Liquid sealing: Close the root valve and fill the pressure system with liquid to achieve liquid sealing. The filling liquid can be kept in the pressure pipe, preventing any pipeline medium from entering the differential pressure transmitter, playing a role in preventing thermal shock and bubbles. Adding appropriate antifreeze can achieve reliable antifreeze.

3.4. Isolation of liquids or gases can be achieved: When measuring liquids or gases, isolation liquid or water can be filled in the heat dissipation device to effectively protect the differential pressure transmitter from corrosive liquids and dirty gases through liquid-liquid or gas-liquid isolation.

3.5 Heat resistance and balance: The liquid overflow during the injection of liquid into the heat dissipation device can maintain the same liquid level height between the two heat dissipation devices, thereby ensuring accurate measurement of the differential pressure transmitter; At the same time, the liquid inside the container can also ensure that the differential pressure transmitter is not damaged by overheating

3.6 Composite measurement of differential pressure, pressure, and temperature: The comprehensive design of pressure transmitters and composite amplifiers can provide pressure and temperature measurement signals for accurate flow calculation at low cost. Reduced the cost of some transmitters and connecting wires that require temperature and pressure compensation.

Note: 1. All flanges have a 4mm convex surface, and PN4.0MPa is a butt welded convex flange

2. The flange standard for pipes with an inner diameter of 450mm to 2000mm is GB/T81-59; Drilling pressure ranging from PN0.6MPa to PN1.6MPa.

3.7 Anti clogging: For steam and liquid measurement, the pressure drilling hole and orifice plate are generally at an angle of 30 ° to 45 ° to overcome the entry of pipeline sediment into the pressure pipe and reduce blockage.

3.8 Structural type and type of throttling element: Structural type: ① Flange clamping type as shown in Figure 2; ② The flange connection type of the pipe section (flange standard: pressure rating of 2.5MPa, JB82-59 for 4.0MPa or according to user requirements) is shown in (Figure 3); ③ The welding method is shown in Figure 4. The external dimensions are shown in Table 1, Table 2, and Table 3 respectively. Types of throttling components: integrated orifice plate, integrated nozzle, integrated 1/4 circular nozzle, integrated wear-resistant orifice plate, integrated circular orifice plate, integrated conical inlet orifice plate, etc

3.9. Easy installation: The orifice plate adopts clamping, welding, and pipe flange connection with the pipeline, with various types and simple installation.

3、 Related calculations and technical performance

1. Basic design basis:

1.1 Calculation formula: The calculation method for intelligent integrated orifice flowmeter and throttling device is the same, according to the national standard for flow measurementGB/T2624-93 and international standard ISO5167-2003 specify the relevant standards for the design of orifice plates and other throttling components and accessoriesProduction and processing, using a separate drilling corner joint pressure method, with a pressure hole diameter of Φ 6mm, as a standard orifice plate; According to national standards and regulationsStandard orifice plates do not require real flow calibration, as long as they are used under the correct conditions, the flow uncertainty of orifice plate measurement can be guaranteed.

Other standard or non-standard throttling components can also be processed for special needs. The formula is as follows:

qm=C×ε÷（1-β4）0.5×π÷4×d2×（2×ρ1×Δp）0.5

In the formula: qm - mass flow rate (Kg/s, kg/s), C - outflow coefficient (dimensionless), ε - beam expansion coefficient (dimensionless), β=d/D ratio of throttle opening to pipeline inner diameter under working conditions (dimensionless) {d=d20 × (1+λ d × (t-20)), D=D20 × (1+λ D × (t-20)), d20 and D20 are the values of orifice opening and pipeline inner diameter at 20 ℃ in mm, respectively,λ d and λ D are the coefficients of linear expansion of the orifice plate and pipeline material in mm/℃ under working conditions, respectively. d represents the opening of the orifice plate under working conditionsDiameter (unit: m), Δ p - differential pressure (unit: Pa), ρ - medium density under working conditions (unit: Kg/m3).

2. Technical performance:

Table 4

Note: The minimum flow rate values of the measured media in the above table should meet the minimum Reynolds number requirements of the throttling element used

2.1 For automated control systems that measure media such as water or liquid, as well as steam and gas with relatively stable flow rates, in order to reduce costsNormally, a range of 5:1 to 9:1 is sufficient. Configure as a throttling device (throttling element can be an orifice plate or nozzle, generallySpeaking of which, the energy-saving effect of using nozzles is significant, and the maintenance cycle can be 2-3 times that of orifice plates, but the processing capacity is difficult and the cost is slightly higher than that of orifice platesDifferential pressure transmitter (with on-site display) and 4-20mA output, capable of heating and pressure compensation for steam. At this time, there are no on-site requirements eitherVery strict.

2.2 For situations with significant flow fluctuations and strict flow control, a range of 14:1 to 30:1 is generally selected,Equipped with throttling device, flow iteration calculator, differential pressure transmitter (with on-site display) and 4-20mA output, it can be used for steamHeating and pressure compensation.

2.3. All flanges have a 4mm convex surface, and PN4.0MPa is a butt welded convex flange

The flange standard for pipes with inner diameters ranging from 450mm to 2000mm is GB/T81-59; Drilling pressure ranging from PN0.6MPa to PN1.6MPa.

6、 STZH intelligent integrated orifice flowmeter selection code

Selection example 1: STZH-200-KIP1W2F11 represents a diameter of DN200, with an orifice plate made of 304 stainless steel, pressure rating ≤ 2.5MPa, medium temperature ≤ 350 ℃, flange clamping type, 4-20mA output without on-site display or temperature and pressure compensation.

Selection example 2: STZH-150-PIP3W3D44 represents a diameter of DN150, with a throttle element of a nozzle made of 304 stainless steel material, pressure rating>4.0MPa, medium temperature ≤ 530 ℃, welded type, equipped with STR-100A, digital display on site, and temperature and pressure compensation.