Cooling and flushing improved lower bearing of submerged sulfuric acid pump

Abstract

The utility model relates to the technical field of sulfuric acid pumps, in particular to an improved cooling and flushing lower bearing of a submerged sulfuric acid pump, which adopts an annular flushing groove without a balance hole design, and utilizes the principle of fluid dynamics to promote pressure difference to be formed at two ends of the flushing groove so as to drive medium fluid to flow directionally. The lower bearing is provided with a spiral flow guide type water retaining ring which is obliquely distributed at an angle of 45 degrees along the periphery of the bearing to effectively restrain the motion trail of flushing water flow, a balance hole is omitted, a lower bearing flushing groove is redesigned, liquid flows through the lower bearing to achieve flushing and cooling, and the problem of abrasion is solved. The new design change is small, the cost is not increased, the size of the auxiliary sealing ring is not changed, the pressure of the balance chamber is increased, leakage is reduced, the volume efficiency is improved, and the pump efficiency is improved by 0.5%-1%. The scheme prolongs the service life of the lower bearing and reduces the maintenance and overhaul period of the pump body.

Description

Technical Field

[0001] This utility model relates to the field of sulfuric acid pump technology, specifically to an improved cooling and flushing submersible sulfuric acid pump lower bearing. Background Technology

[0002] Submersible sulfuric acid pumps are key conveying equipment in the drying and absorption sections of sulfuric acid production processes, primarily responsible for transporting semi-finished and finished sulfuric acid products. This equipment can transport sulfuric acid media with a temperature range of 60–80℃ and a concentration between 80% and 100%.

[0003] The routine maintenance cycle for this type of pump is typically 3 months, with a systemic overhaul cycle set at 12 months. The main vulnerable components identified during overhauls include the lower bearing assembly, inlet sealing ring, and secondary sealing ring. Under extreme operating conditions, wear effects may extend to the impeller back sealing ring, leading to sealing failure.

[0004] Experimental studies show that the failure mechanisms of the above components are significantly correlated: wear failure of the lower bearing will cause an increase in the radial oscillation amplitude of the pump shaft, thereby inducing accelerated wear of the inlet sealing ring and the secondary sealing ring. The timing relationship of this failure process is as follows: Figure 1 As shown.

[0005] Therefore, the key to solving this pump type's failure lies in improving the wear characteristics of the lower bearing. The service life of the lower bearing directly determines the effective operating cycle of other related components.

[0006] Although the lower bearing system of the current submersible sulfuric acid pump operates in a sulfuric acid medium environment and is equipped with an oil tank structure (marked as a rinsing tank in the process document), in actual operation, no effective medium flow is formed in the rinsing tank, and it only maintains a static soaking state.

[0007] Figure 2 The image shows a cross-sectional view of the lower bearing assembly, whose sliding bearing system consists of a sleeve and a bushing. Figure 3 The geometric features of the sleeve are shown in detail. To balance the axial force, the impeller employs a balancing hole design and is equipped with a secondary sealing ring. This balancing principle is based on setting equal-diameter sealing rings on the front and rear cover plates of the impeller, and achieving pressure equalization through the connection between the balancing chamber and the suction chamber. Specifically, several balancing holes are opened in the hub area of ​​the rear cover plate to connect the suction port and the balancing chamber, and their total cross-sectional area should be no less than 5–6 times the cross-sectional area of ​​the sealing ring.

[0008] The pressure in the balancing chamber remains dynamically balanced with the inlet pressure, and the pressure relief hole outside the protective pipe also maintains the same pressure as the inlet. This pressure balancing system causes the pressure difference across the lower bearing to approach zero, thus preventing the formation of media circulation power. This operating condition negatively impacts the pump's operational stability: the lack of continuous flushing and cooling by the lubricating medium leads to a significant increase in the operating temperature of the lower bearing, while the cumulative effect of abrasive wear further exacerbates component wear, ultimately limiting the service life of the lower bearing. Utility Model Content

[0009] To address the shortcomings of existing technologies, this utility model discloses an improved cooling and flushing submersible sulfuric acid pump lower bearing to solve the aforementioned problems.

[0010] This utility model is achieved through the following technical solution:

[0011] This invention provides an improved cooling and flushing lower bearing for a submersible sulfuric acid pump. The lower bearing is mounted on the bottom base of the sulfuric acid pump and is used to bear the radial load of the pump shaft during operation. The lower bearing adopts an annular flushing groove with no balance hole design. The fluid dynamics principle is used to create a pressure difference at both ends of the flushing groove, thereby driving the medium fluid to generate directional flow, realizing the flushing and cooling of the bearing friction surface. The lower bearing is equipped with a spiral guide water baffle ring that is inclined at a 45° angle along the outer circumference of the bearing to effectively constrain the movement trajectory of the flushing water flow.

[0012] Furthermore, the lower bearing includes a sleeve and a bushing, wherein both the sleeve and the bushing are disposed at the lower part of the sulfuric acid pump to support the pump shaft.

[0013] Furthermore, the submersible sulfuric acid pump includes an impeller.

[0014] Furthermore, the impeller is provided with a balancing chamber, the pressure of which is greater than the inlet pressure, to generate the pressure difference.

[0015] Furthermore, the pressure in the balance chamber on the impeller is set to 10-15 (m).

[0016] Furthermore, the submersible sulfuric acid pump also includes an upper bearing for balancing unbalanced axial forces.

[0017] The beneficial effects of this utility model are as follows:

[0018] This invention eliminates the balance hole and redesigns the flushing groove of the lower bearing, enabling liquid to flow through the lower bearing to achieve flushing and cooling, thereby solving the problem of easy wear of the lower bearing.

[0019] The new design method of this utility model involves a small range of modifications and does not significantly increase manufacturing costs. At the same time, the size of the secondary sealing ring remains unchanged, but the pressure inside the balance chamber increases, leakage decreases, and volumetric efficiency increases, which can generally bring a 0.5% to 1% efficiency improvement to the pump.

[0020] This invention solves the problem of easy wear of the lower bearing due to the lack of medium flow in the prior art, extends the service life of the lower bearing, and reduces the maintenance and overhaul cycle of the pump. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a time sequence diagram showing the damage to the lower bearing, the inlet sealing ring, and the secondary sealing ring.

[0023] Figure 2 This is a magnified view of a section of the traditional bearing area;

[0024] Figure 3 This is a diagram of the sleeve structure of a traditional lower bearing;

[0025] Figure 4 This is a partial enlarged view of the bearing area after the modification of this utility model;

[0026] Figure 5 This is a structural diagram of the sleeve of the lower bearing of this utility model;

[0027] The labels in the diagram represent:

[0028] 1. Drain hole; 2. Lower bearing; 3. Balance chamber; 4. Balance hole; 5. Water baffle ring; 6. Annular flushing groove. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] This invention achieves pressure gradient reconstruction in the balance chamber by structurally eliminating the balance orifice, and simultaneously performs topology optimization design on the lower bearing flushing groove based on fluid dynamics principles. This innovative structure constructs a dual-effect fluid control mechanism: firstly, it inherits the pressure balancing function of the traditional balance orifice; secondly, it creates a forced pressure gradient field within the flow channel through geometric innovation. This pressure gradient drives the fluid medium to generate directional flow, forming continuous friction surface flushing and forced convection heat transfer effects, effectively improving the thermodynamic stability of the bearing system.

[0031] Compared with traditional balancing chamber pressure regulation schemes, this design achieves breakthroughs in two key parameters: the balancing chamber working pressure (P_b) strictly satisfies the constraint relationship P_b > Pin (inlet pressure) > P_t (protective tube pressure). This pressure distribution characteristic creates a significant pressure gradient along the lower bearing axis. The non-equilibrium flow model, based on the Navier-Stokes equations, induces continuous laminar flow in the cooling medium. (See attached image.) Figure 4 In the improved structure shown, the annular flushing tank adopts an asymmetric tapering flow channel design, whose hydrodynamic characteristics satisfy the Reynolds similarity criterion, enabling precise control of the flow field morphology. The accompanying 45° inclined spiral guide water-blocking ring structure achieves vector control of the fluid trajectory through secondary flow suppression technology, improving the guiding efficiency by more than 62% compared to the traditional structure.

[0032] In this embodiment, a water-retaining ring device is added to the lower bearing structure to effectively prevent flushing water from directly impacting the upper cover area when flowing through the lower bearing, thereby avoiding corrosion problems. Figure 5 The improved lower bearing bushing structure shown in the diagram increases the pressure inside the pressure balance chamber, causing a dynamic change in the impeller's axial force balance system. Under this condition, the residual axial force that is not fully balanced must be borne by the upper bearing assembly.

[0033] The design process of this embodiment is described as follows:

[0034] 1) Set the pressure H1 in the balance chamber, which is generally set to 10-15 (m).

[0035] 2) Calculate the pressure difference ΔH between the two ends of the sealing ring. mi

[0036] ΔH mi =H-H1ΔH mi =H-H1

[0037] In the formula:

[0038] ΔH mi —Pressure difference across the sealing ring (m)

[0039] H – High-pressure end pressure, which is the pump outlet pressure (m)

[0040] H1—Low-pressure end pressure, which is the pressure in the balance chamber, is generally set to 10-15 (m).

[0041] 3) Calculate the leakage amount Q of the sealing ring.

[0042]

[0043] Q—Leakage of the sealing ring (m) 3 / s)

[0044] R mi —Sealing ring radius (m)

[0045] b — Gap width (m)

[0046] η — fillet factor

[0047] λ — hydraulic resistance coefficient

[0048] l — Gap length (m)

[0049] g — acceleration due to gravity (m / s²) 2 ).

[0050] The fillet coefficient η is related to the ratio of the fillet radius r at the gap inlet to the gap width b, and is selected in the table below:

[0051] r / b 0 0.02 0.04 0.06 0.08 0.1 0.15 0.2 η 1 0.72 0.72 0.38 0.28 0.2 0.08 0.06

[0052] 4) Calculate the diameter d of the flushing tank.

[0053]

[0054] Q—Leakage of the sealing ring (m) 3 / s)

[0055] μ – hydrodynamic or absolute viscosity (Pa·s)

[0056] ΔH mi —Pressure difference across the sealing ring (m)

[0057] l — length of the oil tank.

[0058] The calculated value of 'd' assumes the flushing groove is circular, while the actual flushing grooves for the upper and lower bearings are approximately semi-circular. During the design phase, it is sufficient to ensure that the circumferences of the two are equal.

[0059] This invention proposes a targeted technical solution to the core cause of submersible sulfuric acid pump failures and component damage—abnormal wear of the lower bearing.

[0060] The design improvement of this technical solution has significant feasibility features: First, the scope of improvement is strictly limited to the optimization of the lower bearing structure and the original impeller balance hole diameter parameters, and local adjustments to the drawings can be achieved within the existing production process system; Second, the improvement is implemented based on mature manufacturing processes, and the increase in production costs can be controlled within the engineering error range while ensuring product reliability.

[0061] While maintaining the original dimensions of the secondary sealing ring, the scientific control of the working pressure differential was achieved through optimized design of the pressure gradient in the balancing chamber. Experimental data show that this improvement can reduce leakage by 15%-22%, effectively increase volumetric efficiency by 0.8±0.3 percentage points, and correspond to an overall pump efficiency gain of 0.5% to 1% (95% confidence interval).

[0062] In summary, this invention solves the problem of easy wear of the lower bearing by eliminating the balance hole and redesigning the flushing groove of the lower bearing, thereby achieving the purpose of flushing and cooling by allowing liquid to flow through the lower bearing.

[0063] The new design method of this utility model involves a small range of modifications and does not significantly increase manufacturing costs. At the same time, the size of the secondary sealing ring remains unchanged, but the pressure inside the balance chamber increases, leakage decreases, and volumetric efficiency increases, which can generally bring a 0.5% to 1% efficiency improvement to the pump.

[0064] This invention solves the problem of easy wear of the lower bearing due to the lack of medium flow in the prior art, extends the service life of the lower bearing, and reduces the maintenance and overhaul cycle of the pump.

[0065] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An improved cooled, flushed, sub-liquid-sulfuric-acid pump bearing, said sub- bearing being fitted to the pump bottom pedestal for carrying the pump shaft radial load under operating conditions; characterized in that: The lower bearing adopts an annular flushing groove with no balance hole design. The fluid dynamics principle is used to create a pressure difference at both ends of the flushing groove, thereby driving the medium fluid to generate directional flow, realizing the flushing and cooling of the bearing friction surface. The lower bearing is equipped with a spiral guide water baffle ring that is inclined at a 45° angle along the outer circumference of the bearing to effectively constrain the movement trajectory of the flushing water flow.

2. The improved cooled, flushed, sub-liquid-sulfuric-acid pump bearing of claim 1 wherein, The lower bearing includes a sleeve and a bushing, both of which are located at the bottom of the sulfuric acid pump to support the pump shaft.

3. The improved cooled, flushed, sub- acid pump bearing of claim 1, wherein, The submersible sulfuric acid pump includes an impeller.

4. The improved cooled, flushed, sub- acid pump bearing of claim 3, wherein, The impeller is provided with a balancing chamber, and the pressure in the balancing chamber is greater than the inlet pressure to generate the pressure difference.

5. The improved cooled, flushed, sub- acid pump bearing of claim 4, wherein, The pressure in the balance chamber on the impeller is set to 10-15 (m).

6. The improved cooled, flushed, sub- acid pump bearing of claim 1, wherein, The submersible sulfuric acid pump also includes an upper bearing for balancing unbalanced axial forces.

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