Installation, use and product selection of differential pressure transmitter

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Tianjin Klerui Technology Co., Ltd

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Date: 2017-08-30Read: 9

Differential pressure transmitters are widely used in industries such as petroleum, chemical, power, and metallurgy. This product is mainly used to measure the differential pressure, pressure, and negative pressure of liquids, gases, and vapors. It can also measure the liquid level of open or pressurized containers. Equipped with a throttling device, it can measure the flow rate of liquids, gases, or vapors and convert the measured parameters into 4-20mA DC signal output, which is transmitted to secondary instruments or regulating units for detection or control purposes.
Installation requirements for differential pressure transmitters:
The installation position of differential pressure transmitters on process pipelines is related to the measured medium. In order to achieve better installation results, the following situations should be considered:
Prevent direct contact between the transmitter and corrosive or overheated test media;
Prevent the deposition and blockage of debris in the pressure pipe;
The length of the pressure pipes on both sides of the positive and negative pressure should be as similar as possible;
The liquid column pressure head inside the pressure pipes on both sides of the positive and negative pressure should be balanced;
The pressure pipe is installed in places with small temperature gradients and fluctuations.
When measuring liquid flow rate, the differential pressure transmitter should be installed next to or below the measured pipeline to facilitate the discharge of bubbles into the pipeline; When measuring gas flow, the differential pressure transmitter should be installed next to or on top of the measured pipeline to facilitate the flow of accumulated liquid into the pipeline; When measuring steam flow, the differential pressure transmitter should be installed below the measured pipeline so that the condensate can fill the impulse pipe. Special attention should be paid to prevent the temperature of the medium in contact with the differential pressure transmitter from exceeding the limit temperature of the transmitter when measuring steam or other high-temperature media.

1. Performance Specifications
(Zero benchmark calibration range, under reference conditions, filled with silicone oil and 316 L stainless steel isolation diaphragm.). ）

1.1. Reference accuracy
1.1.1. Digital and intelligent: ± 0.1% calibration range
1.1.2. Simulation, linear: ± 0.2% calibration range
1.2. stability
1.2.1. Digital and intelligent: 6 months, ± 0.1% URL
1.2.2. Simulation, linear: 6 months, ± 0.2% URL
1.3. Environmental temperature impact
1.3.1. Digital and intelligent
Zero point error: ± 0.2% URL/56 ℃
Overall error: ± (0.2% URL+0.18% calibration range)/56 ℃
1.3.2. Simulation, Linear
Zero point error: ± 0.5% URL/56 ℃
Overall error: ± (0.5% URL+0.5% calibration range)/56 ℃
1.4. Static pressure influence
1.4.1. Zero point:
For ranges 4 to 8, the URL is ± 0.2% at 13790kPa; The other ranges are ± 0.25% URL. Zero point error can be corrected online by resetting to zero.
1.4.2. Range:
Can be corrected to ± 0.25% output reading/6895kPa, for range 3, can be corrected to ± 0.5% output reading/6895kPa
1.5. Vibration impact
In any axial direction, the vibration effect at 200Hz is ± 0.05% URL/g
1.6. Power supply impact
Less than ± 0.005% output range/volt.

1.7. Load impact:
There is no load impact unless there is a change in the power supply voltage.
1.8. Electromagnetic interference/radio frequency interference (EMI/RFI impact)
When the field strength reaches 30V/M from 20 to 1000MHz,
Output drift is less than ± 0.1% of the range.
1.9. Installation location impact
The zero drift is at most ± 0.25kPa. All zero drift can be corrected; Has no impact on the measurement range.
2. Functional specifications
2.1. Measurement range: Differential pressure: 0-1.3~6890KPa
Static pressure: 4, 10, 14MPa
2.2. Zero point and range
2.2.1. Digital and Intelligent:
It can be adjusted using the local range and zero buttons, or remotely using a HART controller.
2.2.2. Simulation and linearity:
The range and zero point are continuously adjustable.
2.3. Zero point positive and negative transfer
When zero point negative shift occurs, the lower limit of the range must be greater than or equal to - URL; When zero point is shifted forward, the upper limit of the range must be less than or equal to+URL. Verify that the range is greater than or equal to the small range.
2.4. output
Digital and intelligent:
4～20mA DC， Users can choose linear or square root output, and the digital process variable is superimposed on a 4-20mA DC signal, which can be used by upper computers using the HART protocol.
Simulation, linear:
4～20mA DC, Linear with process pressure.

3051DP differential pressure transmitterSelection Table:

3051DP	Differential pressure transmitter
	code	Range KPa
	3	0-1.3～7.5
	4	0-6.2～37.4
	5	0-31.1～186.8
	6	0-117～690
	7	0-345～2068
	8	0-1170～6890
		code	output
		E	4-20mA
		S	Intelligent
			code name	structural material
				Flanges and fittings		Exhaust/Drain Valve	Isolation diaphragm	Fill with liquid
			22	316 stainless steel		316 stainless steel	316 stainless steel	silicone oil
			23	316 stainless steel		316 stainless steel	Hastelloy C
			24	316 stainless steel		316 stainless steel	Monel
			25	316 stainless steel		316 stainless steel	Tantalum
			33	Hastelloy C		Hastelloy C	Hastelloy C
			35	Hastelloy C		Hastelloy C	Tantalum
			44	Monel		Monel	Monel
				code name	High working pressure MPa
				B-	4
				C-	10
				D-	14
					code	option
					M1	0-Linear Indicator Table
					M2	LED display table
					M3	LCD display table
					B1	Pipe bending bracket
					B2	Board mounted bending bracket
					B3	Pipe mounted flat bracket
					D1	The side relief valve is located at the upper part of the pressure chamber
					D2	The side relief valve is located at the lower part of the pressure chamber
					No note	1/2NPT taper pipe threaded joint
					C2	T-shaped threaded joint M20 × 1.5, with a ball cone connector welded with a rear end of a Ø 14 pressure pipe
					d	Explosion proof type d Ⅱ BT4
					i	Intrinsic safety type ia Ⅱ CT6
					J	Flow transmitter 4-20mA square root output
					s	Stainless steel three valve group

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