During the operation of the diesel fire pump, the vibration in the vertical and axial directions is large, but the horizontal level is normal. Some factors that can be considered are listed below.

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Phenomenon: During the operation of the diesel fire pump, the non-drive end vibrates greatly in the vertical and axial directions. The maximum vibration in the vertical direction can reach about 12.7mm/s, and the maximum in the axial direction can reach about 24.5mm/s, which exceeds the standard value required by the manufacturer (10mm/s). The vibration in the horizontal direction is normal (about 6.1mm/s). During operation, due to heavy vibration, the adjusting bolts of the inlet and outlet expansion joints were loosened. 1. Installation factors: 1) Check the shaft alignment, which meets the manufacturer's requirements (<0.1mm). 2) Check the installation of the inlet and outlet pipes of the pump to see if there is any stress installation. Since the inlet and outlet are connected by expansion joints, there should be no stress. 3) Check the support and fixation of the inlet and outlet pipes of the pump. Currently, the inlet and outlet pipes are fixed through guides (gap 0mm). The manufacturer recommends using U-shaped clips for fixation. 4) Check whether the anchor bolts of the pump body and the steel structure base are not on the same plane, whether they are loose, and whether there are false feet. 5) Check whether the fixation of the entire skid base and the foundation is not on the same plane, or whether there is a problem with the foundation grouting. 2. Operating factors 1) Whether there is air in the inlet during operation and whether cavitation occurs. 2) Whether the flow rate is stable during operation and whether there is intermittent vibration. 3. Design issues 1) The manufacturer believes that the design of the inlet and outlet pipelines is unreasonable at this flow rate. The inlet pipe of the pump cannot be from high to low, but should be lifted. The large and small heads of the pump inlet pipeline should be installed close to the inlet of the pump, not away from the inlet of the pump. The manufacturer's reply is as follows: a) There is poor anchorage onsuction and mainly on discharge of pump's piping. They do not handle the dynamic and fluctuation of piping with water.b) As explained and reported during commissioning, due to suction & discharge pipe sizing, there isvibration in flow. c) The main source of vibration is from water fall in suction, (I mentioned that pump has to be in suction lift), and irregular jump in discharge side for pipe size. In diesel this is more due to some more vibration from Diesel driven.d) The suctions had not being installed for suction lift & reducer is not at pump suction nozzle. Thismakes water break / cavitation & noise in suction lines. 4. Detect the problem: 1) The manufacturer believes that portable vibrators are inaccurate and recommends using magnetic ones. the pickup of vibro measurement has to bemagnetic type (a little bit stronger than one in the photos – in your case itis needle type ) to touch the pump body. 2) It is recommended to change the position of the detection point and not to detect on the pump body. 5. Equipment problems: 1) Check whether the steel structure base of the pump is strong enough and whether there is resonance. 2) Check whether the flow path of the pump body is misaligned during installation. 3) Check the dynamic balance of the pump rotor.