3、 Key technical points (selection+operation control)

　　The effectiveness of high-pressure plunger pumps in transporting sludge relies on the combination of "reasonable selection+proper pretreatment+operation control". The core technical points are as follows:

　　1. Sludge pretreatment: a prerequisite for avoiding pump blockage and wearSludge must undergo pre-treatment before entering the pump, otherwise it may cause plunger jamming, pipeline blockage, or seal damage. Specific steps:

　　Crushing and screening: Use a sludge crusher (such as a double axis shear type) to crush the lumps (mud blocks and fibers with a diameter>5mm) in the sludge, and then filter hard particles (such as stones and metal shavings) through a 10-20 mesh sieve to prevent particles from entering the pump head and scratching the plunger.

　　Viscosity adjustment: If the solid content of the sludge is too high (>70%) or too viscous (viscosity>10000cP), a small amount of water and sludge conditioner (such as polyaluminum chloride) should be added to control the viscosity between 500-5000cP, to avoid excessive reciprocating resistance of the plunger causing motor overload.

　　Anti corrosion pretreatment: If the sludge contains strong acid and alkali (pH<4 or pH>12), a neutralization tank should be installed before the conveying pipeline, or a corrosion-resistant material pump head (such as Hastelloy alloy or fluoroplastic lining) should be directly selected to avoid pump body corrosion and leakage.

　　2. Pump selection parameters: matching sludge characteristics and conveying requirements

　　When selecting, it is important to pay close attention to the following parameters to avoid situations where "a large horse pulls a small car" or "a small pump carries a large load":

　　Work pressure: According to the calculation of "conveying distance x sludge resistance coefficient+head", a 20% -30% margin is usually reserved (for example, if the conveying distance is 300m, a pump with a rated pressure ≥ 15MPa needs to be selected).

　　Flow rate: Calculated based on "daily sludge production ÷ working time", it is necessary to match the processing capacity of subsequent processes (for example, if the daily sludge treatment is 100m ³ and the working time is 20 hours, a pump with a flow rate of ≥ 5m ³/h needs to be selected).

　　Material selection:

　　Ordinary municipal sludge (non corrosive, low particle): The pump head is made of stainless steel 316L and ceramic plunger;

　　Corrosive sludge (such as chemical sludge): The pump head should be lined with Hastelloy C276 or Fluoroplastic (PTFE);

　　High wear sludge (such as construction sludge containing sand and gravel): The pump head is selected with a tungsten carbide plunger and a dual phase steel cylinder body.

　　Sealing method: Priority should be given to mechanical seals and flushing systems (continuously flushing the sealing surface with clean water or neutral liquid) to prevent sludge particles from entering the sealing gap and causing leakage (2-3 times longer than ordinary packing seals).

　　3. Pipeline system design: reduce resistance and blockage risks

　　Pipe diameter selection: The pipe diameter should be 1-2 specifications larger than that of the centrifugal pump during transportation (for example, when the flow rate is 5m ³/h, choose DN50 instead of DN40), reduce the flow rate of sludge in the pipeline (controlled at 0.5-1.5m/s), and minimize pipeline wear and blockage.

　　Pipeline layout: Try to minimize 90 ° elbows (use 45 ° elbows instead), avoid pipeline diameter changes (if diameter changes are required, use gradient joints), and set up one pipeline cleaning port every 50-100m (for easy dredging in case of blockage).

　　Valve selection: Use gate valves or ball valves (to avoid globe valves, which are prone to jamming), with valve diameters consistent with the pipe diameter, and a pressure relief valve installed near the pump outlet (to prevent pipeline pressure from being too high and bursting).

　　4、 Daily maintenance and common troubleshooting

　　1. Daily maintenance (core is "wear and tear prevention, leak prevention")

　　Regular lubrication: Check the lubricating oil level of the plunger guide sleeve daily (using 46 # anti-wear hydraulic oil) and replenish it once a week; Replace the hydraulic oil in the hydraulic oil tank once a month (with a filtration accuracy of ≥ 10 μ m).

　　Replacement of vulnerable parts: Replace the plunger seal ring and mechanical seal every 1000-2000 hours (adjusted according to the degree of sludge wear); Check the wear of the plunger and cylinder every 5000 hours (if the gap is greater than 0.1mm, it needs to be replaced).

　　Cleaning and inspection: Clean the pump inlet filter screen after daily shutdown (to prevent clogging of the filter screen and insufficient suction); Check the pipeline connection parts (flanges, joints) for leaks every week and tighten the bolts in a timely manner.