Booster Pump Thrust Pad HZB330-790A Resolving Uneven Wear and Excessive Vibration for 600MW Units

Created on: 2025-10-22 14:38

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In the maintenance of boiler feed water booster pumps (pre-pumps) within 600MW power plants, engineers frequently encounter failures flagged by "vibration exceeding 0.03 mm" or "axial runout exceeding 0.1 mm." Disassembly often reveals the root cause to be uneven thrust pad wear (with a thickness difference greater than 0.02 mm). Today, referencing the DL584-1996 Technical Specification for Construction and Acceptance of Power Engineering, we will detail the dangers and causes of uneven thrust pad wear, introduce the solution offered by the Dongfang SRI HZB330-790A thrust pad, and share crucial selection guidelines and practical replacement tips for companion parts.

I. Booster Pump Thrust Pad Uneven Wear: 3 Key Hazards + Core Causes

Per Section 7.3.2 of the DL584-1996 standard, the thrust pads for pre-pumps must maintain a "thickness difference ≤ 0.02 mm, and surface flatness ≤ 0.02 mm." Once uneven wear occurs, a chain of failures is triggered:

1. Three Typical Hazards of Uneven Wear

Excessive Vibration Causing Trips: Unevenly worn pads result in unbalanced rotor forces, causing concentricity deviations exceeding 0.03 mm. The pre-pump's vibration double amplitude often spikes from ≤ 0.025 mm to over 0.03 mm (e.g., reaching 7.2 mm/s in some SQ-type pre-pumps). This not only generates abnormal noise but also accelerates friction between the impeller and the casing wear rings, increasing leakage and dropping pump output by 8%–10%.
Axial Runout Destroying Seals: Uneven wear causes the axial positioning to fail, pushing axial runout beyond the ≤ 0.05 mm limit set by DL584-1996. This compresses the mechanical seal's rotating face, widening the seal face gap from ≤ 0.005 mm to over 0.01 mm. Seal water leakage surges from 5 mL/h to 20 mL/h, potentially leading to dry friction and seal burnout.
High Pad Temperature Accelerating Aging: Uneven wear reduces the contact area by up to 50%, intensifying local stress. Temperature rapidly jumps from 60°C to over 80°C, exceeding the typical 75°C protection threshold, triggering the pre-pump to trip and accelerating bearing grease aging (reducing lifespan by up to 40%).

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2. Core Causes of Uneven Wear: Addressed by HZB330-790A Advantages

Cause of Uneven Wear	Common Issue with Standard Pads	HZB330-790A Solution (Dongfang SRI Advantage)
Lack of Precision	Thickness difference > 0.03 mm, leading to uneven force upon installation.	High Precision: Thickness difference ≤ 0.015 mm, flatness ≤ 0.018 mm, exceeding DL584-1996 standards.
Poor Material Wear Resistance	Standard brass material (Hardness 60 HB), high wear rate.	Durable Material: ZCuSn10Pb1 Tin Bronze (Hardness 85 HB), increasing wear life by 40%.
Ineffective Cooling	Aged cooling jacket O-rings causing air leaks and poor heat dissipation.	Integrated Solution: Paired with our Fluororubber O-ring (HZB253-640-03-09, rated 200°C) to ensure cooling integrity.

II. HZB330-790A: 3 Key Advantages + Applicable Models

The Dongfang SRI Boiler Feed Pump Booster Pump Thrust Pad HZB330-790A is specifically designed for 600MW unit pre-pumps, precisely engineered to eliminate uneven wear:

1. Precision Compliance: Root Cause Prevention

Strictly manufactured according to DL584-1996: Single pad thickness difference ≤ 0.015 mm (batch deviation ≤ 0.02 mm), surface roughness Ra ≤ 0.8 μm. This ensures uniform force distribution on the rotor post-installation, preventing localized wear. After replacing a pad at a power plant, the pre-pump vibration dropped from 7.2 mm/s to 2.1 mm/s, far below the 3.8 mm/s acceptance limit.

2. Durable Material: Extended Life to 12,000 Hours

Utilizing ZCuSn10Pb1 Tin Bronze (conforming to GB/T1176-2013), containing 10% tin and 1% lead. It combines high hardness with toughness, allowing it to withstand the residual axial force of the pre-pump (typically 5–8 kN). The lifespan is extended by 30% compared to standard brass pads, significantly reducing replacement frequency.

III. Companion Part Selection: Synergy with HZB330-790A to Avoid Secondary Failure

Stable booster pump operation requires the Thrust Pad + Companion Parts to work in synergy. Dongfang SRI provides a full set of core spares:

Component	Part Number	Material / Key Spec	Synergistic Reliability Function with HZB330-790A
Cooling Jacket O-Ring	HZB253-640-03-09	Fluororubber (200°C rated)	Seals the cooling jacket to prevent air leakage, ensuring proper heat dissipation for the HZB330-790A and preventing thermal uneven wear.
Water Control Ring	HZB253-640-01-07	Stainless Steel	Precisely guides sealing water flow, preventing direct water jet impact on the thrust pad and protecting the mechanical seal from dry running.
Shaft Sleeve	HZB253-640-01-04	Anti-Cavitation Stainless Steel (304)	Protects the pump shaft from wear and maintains rotor concentricity in conjunction with the HZB330-790A.
Gasket	HZB253-640-02-07 / HZB253-640-03-07	Asbestos-Free, Thickness Dev. ≤ 0.01 mm	Ensures a perfect seal between pump cover and casing, preventing leakage that could compromise thrust pad lubrication.

A 600MW power plant, after simultaneously replacing the HZB330-790A pads and the above companion parts, reported continuous pre-pump operation for three months. Thrust pad temperature remained stable at 62–65°C, with no signs of uneven wear and axial runout controlled to within 0.03 mm. Secure your whole system! Request a full spares package quote tailored for 600MW pre-pumps today!

IV. Practical Operation Tips: Replacement and Acceptance per DL584-1996

1. Pre-Replacement Preparation

Tools: Micrometer with 0.001 mm accuracy (for measuring thickness deviation), dial indicator (for measuring axial runout), torque wrench (for bolt tightening).
Disassembly: First, remove the pre-pump free-end cover and mechanical seal, then carefully extract the old thrust pads (ensure to mark the installation direction).

2. Installation and Acceptance (Conforming to DL584-1996 Section 7.3.4)

Install HZB330-790A: Ensure the pad surface contact area with the thrust disc is ≥ 90%. Control the axial clearance (end float) to 0.15–0.2 mm.
Synchronous Replacement of Companion Parts: The cooling jacket O-ring (HZB253-640-03-09) requires sealant application. The gaskets (HZB253-640-02-07) must be tightened with uniform force.
Acceptance: Conduct a 30-minute no-load test run. Acceptance criteria: Vibration ≤ 0.025 mm, temperature ≤ 70°C, and axial runout ≤ 0.05 mm.

The Dongfang SRI Booster Pump Thrust Pad HZB330-790A, with its characteristics of "high precision, superior wear resistance, and wide adaptability," resolves vibration and axial runout failures caused by uneven wear. Paired with our complete set of companion parts, it is engineered to guarantee the long-cycle operation of your 600MW unit pre-pumps.

Booster Pump Thrust Bearing Pad HZB330-790A

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