Delta Flow Sensor

NegotiableUpdate on 12/15

Model

Nature of the Manufacturer: Producers

Product Category

Place of Origin

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Overview

The HC-HLV series Deltaba flow sensor is a type of flow sensor designed using differential pressure working principle and plug-in installation method. In terms of working principle, this is a special throttling device that generates a high-pressure distribution area in the upstream direction and a low-pressure distribution area in the downstream direction when fluid flows through the sensor. Its output is differential pressure.

Product Details

1、 Application method

HC-HLV seriesDelta Flow SensorIt is a flow sensor designed and generated using the principle of differential pressure and plug-in installation method.

2、 Pressure collection method

HC-HLV seriesDelta Flow SensorThe pressure measurement method is achieved through a probe (or probe) with a diameter of approximately 20 millimeters, which has two rows of unevenly distributed 8 millimeter pressure holes in front and behind the probe. By averaging the different pressures (/flow rates) of the pipeline from top to bottom (/from left to right) through these two rows of holes, a differential pressure is formed (due to slow flow rates on both sides of the pipeline and fast flow rates in the middle), which can be used to calculate the mass flow rate or volume flow rate.

3、 Measurement method

The flow calculation of HC-HLV series Deltaba is basically based on the requirements of the EU standard fluid softwareThe method of calculation. Specifically, the following calculation formulas are used:

among which

Qm :

Mass flow rate, measured in kg/s;

ζ:

The resistance parameter (blocking coefficient) of the probe is dimensionless; (Each probe has a value, which is included in the calculation report)

ε:

Coefficient of expansion; When it is an incompressible medium, it is 1. When measuring gases, it is necessary to add and check the table. Dimensionless;

d：

The inner diameter of the pipeline, measured in meters

dp：

Differential pressure, measured parameter, unit: pa=n/? =kg/s2m

ρB ：

Medium density under operating conditions, in kg/m3

So, based on the differential pressure, inner diameter, the blocking coefficient provided by the probe itself, and the working density of the medium, the mass flow rate can be calculated. The problem is the working density, which may require temperature and pressure compensation. This can be done by looking up a table (ρ B=f (t, P)) or by calling (using) the standard density calculation subroutine built into most PLCs or DCS. For gases, it is necessary to determine the specific coefficient of expansion.

4、 Installation method

Installation requirements:

1. The measuring section for installing the detection rod should be straight, and the length of the upstream and downstream straight pipe sections should refer to the length specified in the table below.

serial number	Form of local resistance component on the upstream side	upstream side			downtourside
		No rectifier		There is a rectifier
		On the same plane as the detection rod	Not in the same plane as the detection rod	There is a rectifier
1	There is a 90 ° elbow or tee	7D	9D	6D	3D
2	There are two 90 ° elbows in the same plane	9D	14D	8D	3D
3	There are two 90 ° elbows in different planes	19D	24D	9D	4D
4	Change in pipeline diameter (expansion or contraction)	8D	8D	8D	3D
5	Partially opened gate valves, ball valves, or other throttling valves	24D	24D	9D	4D

Note: 1 * D is the nominal diameter of the pipeline, and the given data is the length from the second bend.2. The allowable deviation range for the angle of the detection rod insertion position is shown in the figure.3. For vertical pipelines, the detection rod can be installed at any position along the circumference of the pipeline at 360 ° in the horizontal plane, and the high and low pressure impulse pipe joints should be on the same horizontal plane. For horizontal pipelines, the insertion position of the detection rod when measuring liquids should be within a range of 45 ° or less from the centerline of the horizontal plane of the pipeline cross-section; When measuring gas, the insertion position of the detection rod should be within a range of 45 ° or more from the centerline of the horizontal plane of the pipeline cross-section; When measuring steam, the detection rod should be inserted horizontally, as shown in the figure:4. The opening size on the pipeline is Φ 35.5. The compensating pressure transmitter is installed on the front straight pipe section, and the temperature transmitter (or platinum resistor) is installed on the rear straight pipe section at a distance of 2D from the throttling device.