What are the standards for commissioning and acceptance of Roots blower after installation?

The commissioning and acceptance of Roots blower after installation is the key link to ensure the long-term stable operation of the equipment, which needs to be carried out around the four core dimensions of appearance and installation accuracy, operation parameters, performance indicators, safety and auxiliary systems. The specific standards are as follows, and some indicators need to be adjusted in combination with the equipment manual (such as model, pressure/flow parameters):

A, appearance and installation foundation acceptance (static inspection)

Before commissioning and acceptance, it is necessary to confirm the "basic compliance" of equipment installation and eliminate static hidden dangers:

Foundation and fixation

The strength of concrete for equipment foundation shall meet the design requirements (usually ≥C20 or higher), with no cracks and hollowing on the surface, and the foundation flatness error shall be 2mm/m or less;

The anchor bolts shall be installed firmly without looseness and corrosion, and the tightening torque of bolts shall meet the requirements of the equipment manual (for example, M20 bolt torque is about 180-220 nm, please refer to the specific specifications);

Shims (or damping pads) between the equipment base and foundation shall be evenly arranged, with no more than 3 pieces in each group, and shall be closely attached to the base and foundation (check with a 0.05mm feeler gauge, and the insertion depth shall not exceed 1/3 of the length of the shim).

Installation of pipelines and accessories

The air inlet/exhaust pipeline is straight, the bracket is firmly fixed and there is no obvious deformation; Flexible joints (such as rubber or metal bellows) are used to connect the pipeline with the inlet and outlet of the fan, so as to avoid hard connection to transmit vibration, and the flexible joints are free from damage and dislocation;

The safety valve, pressure gauge, check valve and other accessories are installed in correct positions (for example, the safety valve should be installed vertically in the exhaust pipe near the fan) and passed the verification (the accuracy of the pressure gauge is ≥1.6, and the jumping pressure of the safety valve is 1.05-1.1 times of the design pressure);

There is no leakage in the lubricating oil pipeline (gear box and bearing box), the oil level gauge and oil temperature sensor are firmly installed, and the valve switch of the oil pipeline is flexible.

Appearance and component integrity

Fan casing, rotor, bearing and other components are free from collision, deformation and corrosion, and seals (shaft seal and end cover seal) are installed in place without damage;

The motor is aligned with the coupling (or pulley) of the fan, and the protective cover is firmly installed and clearly marked (such as rotation direction arrow and danger warning);

The wiring of the electrical control cabinet is standard, the terminals are not loose, the indicator lights and buttons function normally, and the grounding resistance is ≤4Ω (it needs to be detected by a grounding resistance tester).

Second, the installation accuracy acceptance (geometric accuracy inspection)

Check the "accuracy" of equipment installation through professional tools to avoid abnormal operation caused by deviation:

Check the testing tools of project acceptance standard (refer to GB/T 28882-2012 Code for Acceptance Test of Industrial Fans).

Coaxiality of coupling (radial) When the diameter of coupling is less than ≤300mm, the error is less than ≤0.1mm；; When the diameter is greater than ＞300mm, the error is ≤ 0.15 mm dial indicator+magnetic seat.

The runout error of the coupling end face is less than or equal to 0.05 mm/m (that is, the runout within each meter is less than 0.05 mm). Dial indicator+magnetic seat.

Parallelism of belt pulley, deviation of two wheel end faces ≤0.5mm/m, axial dislocation ≤ 1 mm, ruler+feeler gauge.

The vertical (fan axis direction) error of bearing seat levelness is ≤0.1mm/m, and the horizontal error is ≤ 0.2 mm/m Level (accuracy is 0.02mm/m).

Three, no-load commissioning acceptance (dynamic inspection)

When the equipment is not connected to the load (the valves of the inlet/outlet pipes are open and there is no back pressure), it shall be run at no-load for 1-2 hours, and the following indicators shall be mainly checked:

Operational stability

When the fan is started, there is no jamming and abnormal noise (such as metal rubbing sound and violent vibration sound), and there is no shell rubbing phenomenon of the rotor during operation (which can be judged by listening to the needle sticking to the casing);

The running current of the motor is stable, and does not exceed 50% of the rated current (because the load is extremely small when there is no load, too high current may be caused by motor wiring error or bearing jam).

Vibration and noise

Vibration value: measured at fan bearing seat and motor bearing seat, the horizontal/vertical/axial vibration speed is ≤4.5mm/s (meeting the requirements of ISO 10816-3 for "rigidly mounted rotating machinery");

Noise value: measured at a distance of 1m from the equipment, the noise of the whole machine is ≤85dB (A) (if there is no special requirement, it is ≤80dB (A) if it is a low-noise fan), and there is no obvious noise.

Temperature control

Bearing temperature: after running for 1 hour, the rolling bearing temperature is ≤70℃ (when the ambient temperature is ≤35℃) and the temperature rise is ≤40℃ (temperature rise = bearing temperature-ambient temperature); Sliding bearing temperature ≤65℃, temperature rise ≤ 35℃;

Motor temperature: motor stator winding temperature ≤120℃(Class B insulation) or ≤155℃(Class F insulation), which shall meet the requirements of motor insulation grade;

Lubricating oil temperature: gear box lubricating oil temperature ≤60℃ (if oil cooling system is provided, the oil temperature should be controlled at 30-55℃).

sealability

There is no obvious leakage at the shaft seal (if the oil and gas leakage is ≤5 drops/hour, there should be no visible leakage if it is a mechanical seal);

There is no leakage in the lubricating oil path, and the oil level is kept at 1/2-2/3 of the oil level gauge, with no obvious drop.

IV. Acceptance of load commissioning (performance verification)

After the no-load is qualified, connect the actual working load (such as opening the downstream pipeline valve and adjusting it to the design pressure/flow) and run continuously for 4-8 hours. The acceptance criteria are as follows:

Core performance index

Air volume: the deviation between the measured air volume and the designed air volume is ≤ 5% (measured by orifice flowmeter and vortex flowmeter in the stable section of the intake/exhaust pipeline);

Wind pressure: the deviation between the measured exhaust pressure and the design pressure is ≤ 3% (based on the pressure gauge reading near the outlet of the fan, and the influence of pipeline resistance should be excluded);

Motor current: At full load, the current shall not exceed 105% of the rated current, and there shall be no obvious fluctuation (fluctuation range ≤5%).

Operation stability and protection

The equipment operates under the design load without abnormal vibration and noise (the index is the same as no load, and the vibration speed can be relaxed to ≤6.3mm/s), and the temperature of bearings and motors does not exceed the standard;

The linkage of safety protection system is normal: in case of overpressure, the safety valve will automatically take off (the deviation of take-off pressure is less than or equal to 5%), and in case of overtemperature (the oil temperature/bearing temperature exceeds the standard), the control cabinet will automatically give an alarm and stop, and the stopping process will be smooth and without impact.

Piping and system

There is no vibration transmission in the intake/exhaust pipeline (it can be judged by touching the pipeline, and there is no obvious resonance), and there is no leakage at the flange joint (it is smeared with soapy water, and no bubbles are generated);

If auxiliary equipment such as silencers and filters are provided, it is necessary to confirm that the noise reduction effect of silencers is up to standard (the noise of downstream measuring points is 15-20dB (A) lower than that of fan outlet), and the filter pressure difference is ≤ the design value (for example, the initial pressure difference of filter element is ≤5kPa).

V. Acceptance documents and closing

After commissioning and acceptance, complete acceptance documents shall be arranged as the basis for equipment delivery:

Acceptance records: including visual inspection, installation accuracy, measured data of no-load/load operation, which shall be signed by Party A, Party B (installer) and the supervisor for confirmation;

Supporting materials: equipment manual, certificate of approval, calibration report of accessories (such as pressure gauge and safety valve calibration sheet), and electrical grounding test report;

Legacy: If there are slight deviations (such as slightly higher noise but meeting industry standards), the rectification plan, time limit and re-inspection requirements should be clarified.

Key reference standard

National standards: GB/T 28882-2012 Acceptance Test Specification for Industrial Fans and GB/T 19073-2008 Technical Conditions for Roots Blowers;

Industry standard: JB/T 8941.1-1999 Roots Blower for General Use Part 1: Technical Conditions;

Installation and Use Manual provided by the equipment manufacturer (give priority to the manufacturer's specific requirements, such as vibration and temperature limits under special working conditions).

Through the above full-dimensional acceptance, the installation quality of Roots blower can be ensured to meet the standard, and the later failures (such as bearing wear, rotor seizure, pipeline rupture, etc.) caused by initial hidden dangers can be avoided, and the service life of the equipment can be prolonged.