CN201708623U - Electrical machine of boiler water pump of stuffing box with unidirectional sealing function - Google Patents

Abstract

The utility model relates to an electrical machine of a boiler water pump of a stuffing box with a unidirectional sealing function, which comprises an electrical machine and a boiler water pump, wherein the electrical machine comprises a sealing container, a stator, a rotor and a shaft; the outward extending end of the shaft is connected with the boiler water pump; a connection place between the electrical machine and the boiler water pump is a heat neck; a shaft at the heat neck is a shaft extension place; the shaft of the shaft extension place is sleeved with at least two abnormally-shaped seal rings; and the external axial end face of each abnormally-shaped seal ring is provided with a groove. A sealing gap delta formed by the inner circle of each abnormally-shaped seal ring and the outer circle of the shaft extension place is filled with water to form into an additional water lubricated bearing, so that the cantilever degree of the traditionally-designed cantilever quantity structure is shortened at the 1/4-1/6 of the original cantilever degree, thereby reducing the deflection at 1/64-1/216, improving the critical rotate speed at 30-50%, effectively preventing the bearing place from being bended and the conductive bearing at a pump end from being invalid prematurely, reducing the leakage quantity of failure leakage at the 1/10 of the original leakage quantity, almost being capable of completely and automatically preventing the high-temperature boiler water from entering into the electric machine, and preventing the insulation of winding of the electric machine from being burnt.

Description

Boiler pump motor with one-way sealing property stuffing box

Technical field

The utility model belongs to the drive motors technical field of large turbo-type generator group boiler water circulating pump, is specifically related to a kind of boiler pump motor.

Background technology

Boiler pump motor is the driving arrangement that is used to drive big power station's forced circulation pump, the water-in and water-out pipeline of forced circulation pump is connected in the pipe-line system of boiler, for the circulation of boiler working medium provides power, improve generating efficiency for reducing fuel consumption, the parameter of boiler working medium has reached pressure 30MPa, so-called ultra supercritical parameter boiler one turbine system of temperature more than 300 ℃.Boiler pump motor and forced circulation pump are direct connections, the 1950's at initial stage of boiler pump motor development to the sixties, can not find of the movable sealing of a kind of suitable material at that time as pump one motor direct connection position, therefore the pioneer of boiler pump motor design proposes, utilize the Incoercibility of water, boiler pump motor is installed in the airtight container, and the technology that adopts a kind of hot neck 2 reduces the heat insulation mode of heat conduction, thermal convection, the condition of work of boiler pump motor remained in the water environment below 50 ℃ work.Obvious boiler pump motor is a type in the wet stator type submersible motor, existing so far up to ten thousand this boiler pump motors of movable sealing without spin, and this boiler pump motor of movable sealing is without spin worked in the big power station all over the world.The formal title of boiler pump motor is the wet stator motor of no stuffing box.Yet also expose some problems in the operating experience of over half a century, the problem that often runs into is as follows:

1, referring to Fig. 1, airtight container 1 for the Incoercibility design that keeps water, but still there are many indispensable seal points, the envelope dateline 3 of drawing as the motor coil conducting end, for the assembling motor must separate airtight container 1 and end cap 4, sealing 5 between them is for reducing the HP cooler 6 of boiler pump motor working temperature, joint sealing 7 etc., nowhere must guarantee seepage, as long as there is place sealing to puncture, then the Incoercibility of water is destroyed, the boiler working medium of high pressure-temperature (stove water) is promptly charged into motor cavity inside, and the interior medium (water that normal temperature is about 50 ℃) of motor is risen to more than 250 ℃, and motor lost efficacy because of winding insulation burns.This class fault accounts for the failure rate about 20% according to statistics.

2, in order to improve the cooling effect of hot neck, the axle in hot neck designs carefully and long shape as far as possible, and the impeller of stove water pump is installed in the end of shaft extension, forms the structure of cantilever beam.Amount of deflection is increased, and critical whirling speed descends, and has particularly increased the work load of pump end motor guide bearing.This unreasonable structure causes pump end guide bearing premature failure, shaft extension fault such as easily bend.This type of fault accounts for total failare more than 30% according to statistics.

Summary of the invention

In order to solve boiler pump motor pump end guide bearing premature failure, shaft extension fault and sealing problem such as easily bend, the utility model provides a kind of boiler pump motor with one-way sealing property stuffing box under the prerequisite that does not change existing boiler pump motor structure.

The Technological improvement plan of realizing above-mentioned purpose is such:

Boiler pump motor with one-way sealing property stuffing box comprises motor and stove water pump, motor comprises airtight container, stator, rotor and axle, the overhanging end of axle is connecting the stove water pump, and the junction between motor and the stove water pump is hot neck, and the shaft part axle that is in hot neck position is called the shaft extension place of axle; Be arranged with plural special-shaped seal ring on the axle at described shaft extension place, the outer axial end face of described each special-shaped seal ring is provided with groove.

Gap between described special-shaped seal ring and the axle is a seal clearance, and the monolateral value of described seal clearance is the 0.2-0.25 millimeter.

Groove cross section on the described special-shaped seal ring is for trapezoidal.

The shaft extension place of described axle is arranged with three～five special-shaped seal rings.

Described profiled seal loop material is the flexible swollen graphite that rises.

Adopt the utility model that 2 significant technique effects are arranged:

One: after the one-way sealing stuffing box is set, be full of by water in the seal clearance δ 2 that forms by the cylindrical at the interior circle of flexible graphite sealing ring and shaft extension place 8, form an additional water lubriucated bearing, make the cantilever degree of the cantilever amount structure of traditional design shorten to original 1/4-1/6, thereby make amount of deflection drop to 1/64-1/216, critical whirling speed improves 30-50%, prevents that effectively the bearing place from bending and pump end guide bearing premature failure;

Its two: because seal clearance δ 2 is 1/10 of hot neck place gap delta 1, the amount of leakage revealed of breaking down also is reduced to original 1/10, and described sealing ring is the different in nature sealing ring of lip ring mouth, the trend that auto-closing is arranged in the leakage of breaking down property, make seal clearance trend towards 0, can stop fully automatically that almost high temperature furnace water enters motor internal, prevent that the accident that the motor windings insulation is burnt from taking place.

Description of drawings

Fig. 1 is the utility model structural representation,

Fig. 2 is the partial enlarged drawing of Fig. 1,

Fig. 3 is the K-K cutaway view of Fig. 2,

Fig. 4 is the utility model performance principle schematic.

Embodiment

Below in conjunction with accompanying drawing, the utility model is further described by embodiment.

Embodiment:

Referring to Fig. 1, the boiler pump motor with one-way sealing property stuffing box comprises motor and stove water pump, and motor comprises airtight container 1, stator, rotor and axle 11, and the overhanging end of axle 11 is connecting the stove water pump, and the junction between motor and the stove water pump is hot neck 2.The axle at described hot neck 2 places is shaft extension place 8, is set with three special-shaped seal rings 9 on the axle 11 at described shaft extension place 8; The outer axial end face of each special-shaped seal ring 9 offers groove, and the groove cross section on the special-shaped seal ring 9 is for trapezoidal, and the gap between the inner cylinder face 10 of special-shaped seal ring 9 and the axle 11 is seal clearance δ ₂, seal clearance δ ₂Be the 0.2-0.25 millimeter, see Fig. 2 and Fig. 3.

The specification requirement of special-shaped seal ring 9 is: working temperature-100～1600 ℃, coefficient of friction 0.13～0.15, operating pressure 20～50MPa, allow linear velocity 40m/s, inverted trapezoidal groove on the special-shaped seal ring of the flexible swollen graphite material that rises forms the lip structure, and the gap between the inner cylinder face 10 of special-shaped seal ring 9 and the axle 11 is seal clearance δ ₂, seal clearance δ ₂Be the 0.2-0.25 millimeter; Gap delta between airtight container 1 hot neck 2 places and the axle 11 ₁=2～2.5mm is because seal clearance δ ₂Very little, so hydraulic resistance loss Δ Very big, bigger leakage flow Δ Q is through the gap, δ ₂Promptly can produce bigger drag losses.

$\mathrm{\Δ}{H}_{{\mathrm{\δ}}_1}=\mathrm{\ΔQ}\·R_{{\mathrm{\δ}}_1}....................................\left(1\right)m\left(H_{2}0\right)$

$R_{{\mathrm{\&delta;}}_1}={\mathrm{\&xi;}}_{{\mathrm{\&delta;}}_1}\&CenterDot;\frac{l_{{\mathrm{\&delta;}}_1}}{S_{{\mathrm{\&delta;}}_1}}.....................................................\left(2\right)m/({\mathrm{<figure-callout\; id="3"\; label="m"\; filenames="HSA00000179298900011.png"\; state="\{\{state\}\}">m</figure-callout>}}^3/s)$

$S_{{\mathrm{\&delta;}}_1}=\mathrm{\&pi;D}{\mathrm{\&delta;}}_1............................................................\left(3\right)m^2$

In the formula

Be seal clearance δ ₁Variable water resistance, big more by the visible water resistance of (1) formula, the drag losses that identical leakage flow forms

Big more, water resistance

Height with special-shaped seal ring

Be directly proportional and the area in gap

Be inversely proportional to.

Be variable water resistance coefficient,

Desirable 1.0.

When boiler pump motor when mounted, should be through water filling port (12) to boiler pump motor pressure vessel (1) internal water flooding, fill with inner chamber for making water, in boiler pump motor highest point position exhaust outlet (13) is arranged, this exhaust outlet also is to observe the full observation panel of water filling in the pressure vessel, the annular gap face on the face of cylinder of circle and axle can exhaust and spilling water in the special-shaped seal ring, and is just the same with the structure of existing boiler pump motor.When HTHP stove water leaked in boiler pump motor pressure vessel tube, P1＞P2 made the tongue (14) of the lip structure of special-shaped seal ring be subjected to pressing to the surperficial convergent force of axle (11), and under the effect of convergent force, the gap of sealing ring finally makes δ ₂=0,

Promptly closed seal clearance δ fully ₁, make HTHP stove water can not or very little enter the operational environment that the pressure vessel tube is a boiler pump motor.Just, the special-shaped seal ring by flexible graphite material (or similar material make band seal lip) has: the effect of a. one-way sealing, its direction are to stop HTHP stove water to enter the machine operation environment, and the protection boiler pump motor is not scorched; B. the effect of proportional seal valve, promptly there is very micro-HTHP stove water to infiltrate motor, and the motor HP cooler can digest the increment of this heat of balance, just still allows boiler pump motor normally to move, and prolongs the running time of band minor failure for this visual plant of boiler pump motor; The 0-A section, leakage rate is very little, and tongue is not out of shape; When leakage rate increased, distortion had taken place in lip, arrived the critical point of A point deformation, and the A point is distortion critical point, gap delta ₂→ 0, resistance increases sharply

Enter the B-C section, in the tiny leakage stage, see Fig. 4.C. special-shaped seal ring is arranged on the close impeller place of shaft extension, has played the 3rd guide shaft to bearing.Make the cantilever beam of impeller stretch out the long original 1/4-1/6 that reduces to, it is original 16%～5% that the amount of deflection of shaft extension drops to, and the load of the top guide bearing of original structure is greatly alleviated, and also prevents the crooked and distortion of shaft extension.

Claims (5)

1. the boiler pump motor that has one-way sealing property stuffing box, comprise motor and stove water pump, motor comprises airtight container, stator, rotor and axle, the overhanging end of axle is connecting the stove water pump, junction between motor and the stove water pump is hot neck, the shaft part axle that is in hot neck position is called the shaft extension place of axle, it is characterized in that: be arranged with plural special-shaped seal ring on the axle at described shaft extension place, the outer axial end face of described each special-shaped seal ring is provided with groove.

2. the boiler pump motor with one-way sealing property stuffing box according to claim 1 is characterized in that: the gap between described special-shaped seal ring and the axle is a seal clearance, and the monolateral value of described seal clearance is the 0.2-0.25 millimeter.

3. the boiler pump motor with one-way sealing property stuffing box according to claim 1 is characterized in that: the groove cross section on the described special-shaped seal ring is for trapezoidal.

4. according to claim 1 or 2 or 3 described boiler pump motors with one-way sealing property stuffing box, it is characterized in that: the shaft extension place of described axle is arranged with three～five special-shaped seal rings.

5. according to claim 1 or 2 or 3 described boiler pump motors with one-way sealing property stuffing box, it is characterized in that: described profiled seal loop material is the flexible swollen graphite that rises.

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