Maintenance of M&C SP2006-H/DIL Sampling Probe

Interpretation:

The heating function can prevent the sample gas from falling below the acid dew point inside the probe, avoiding corrosive condensate from damaging the filter element or orifice plate. If the dew point of the process gas is higher than 180 ° C, the 280 ° C version must be selected.

The inlet pressure of the dilution gas is relatively high (at least 4.5 bar) because the required flow rate and pressure difference of the injector still need to be ensured after passing through the internal pressure reducing valve.

The process pressure cannot be lower than 0.9 bar abs (i.e. micro negative pressure), otherwise the injector may not be able to form sufficient vacuum. If the process is at normal pressure or slightly positive pressure (such as flue gas), it is fully applicable.

Installation and Connection: Step by Step

4.1 Installation position and direction

Sampling points should be selected at locations where the airflow is uniform and can represent the average composition of the process, avoiding proximity to bends, baffles, or blind spots.

The probe is recommended to be installed horizontally and tilted about 10 ° towards the process direction to facilitate the reflux of condensate to the process pipeline and reduce corrosion.

It is recommended to install the diluted sample gas outlet of the probe facing downwards (not functionally necessary, but convenient for pipeline drainage).

Adequate space should be reserved around to facilitate the disassembly and maintenance of the filter chamber cover (at least 500 mm of front space).

4.2 Flanges and Insertion Tubes

The standard installation flange is 3 "150 lbs, and a 4" flange or adapter is available as an option.

The pre filter or sampling tube is screwed into the probe flange through a G 3/4 "internal thread. Commonly used ceramic filters (2 μ m, 150 mm long) or fiberglass filters (0.1 μ m).

4.3 Gas path connection

All air circuit joints are located inside the FRP (fiberglass) casing at the bottom of the probe, and are introduced into the pipeline through the CES cable entry port (suitable for outer diameters of 36-70 mm). The casing must be opened before connection, and then closed after completion.

Remarks on the size of pipeline functional joints

Test gas (calibration gas) inlet 1/4 "pipe joint with one-way valve, opening pressure 0.7 bar

The 1/4 "pipe joint at the dilution gas inlet needs to be connected to a precision pressure reducing valve and pressure gauge

Low pressure vacuum gauge interface 1/4 "pipe joint is used to monitor the vacuum degree of the injector

The 3/8 "pipe joint at the outlet of the diluted sample gas (to the analyzer) must use corrosion-resistant, low adsorption heating or tracing tubes

Bypass air inlet (optional) 1/4 "pipe joint is only used when configuring bypass injector/B or/BR

Bypass gas outlet (optional) 1/4 "pipe joint can be emptied or returned to the process

Undiluted sample gas outlet (optional) 1/4 "pipe joint for parallel measurement of undiluted sample gas

Backblowing inlet 3/8 "pipe joint for pulse blowback cleaning filter

Key precautions:

When all hoses are connected to stainless steel fittings, a support sleeve (sheath) must be used to prevent the hoses from being cut or leaking.

Dilution gas, bypass gas, and blowback gas must be clean, dry, and oil-free. Recommend using 99.999% nitrogen or instrument air.

If the moisture content of the sample gas is high, the outlet pipeline of the diluted sample gas must be traced to>dew point temperature, otherwise condensation may occur, leading to measurement deviation.

4.4 Electrical Connections

Heating and temperature control are achieved through an electronic controller (model 70304G) installed on the side of the probe. Wiring requirements:

Power supply: 230V or 115V (according to the model label), minimum wire diameter of 3 × 1.5 mm ², must be connected to an external main switch and overcurrent protection (fuse).

Low temperature alarm contact (terminals 11-12): The contact will activate when the probe temperature is below the set value of 30 ° C. It is strongly recommended to connect this alarm signal in series to the power supply circuit of the dilution gas and bypass gas solenoid valves. Once there is a low temperature fault, the dilution gas source will be automatically cut off to prevent unheated sample gas from condensing and corroding key components inside the probe.

PT100 or NiCr Ni thermocouple is used as a temperature sensor located inside the heating block.

The cable entry port must use high-temperature resistant cables (such as silicone rubber insulation) and be properly sealed.

Initial startup steps

The initial operation on site must strictly follow the following sequence, otherwise it may damage the probe or affect the analysis data.

5.1 Power on preheating

Confirm that the power supply voltage is consistent with the model label.

Close the external power switch and observe the temperature controller (70304G) display. The set temperature value has been pre-set at the factory (usually 180 ° C or 280 ° C) and can be adjusted according to the process.

Heating time is about 2 hours. When the probe temperature reaches the "set value -30 ° C", the low temperature alarm is released before proceeding to the next step.