RU2268784C1 - Screen shaker - Google Patents

Abstract

FIELD: petroleum industry; natural gas industry; production of devices for drilling mud fluid cleaning.

SUBSTANCE: the invention is pertaining to the field of petroleum industry and natural gas industry, in particular, to production of devices for drilling mud fluid cleaning. The screen shaker consists of: a base; a frame mounted with the help of dampers; screen plates fixed on the frame; a device of changing a tilt angle of the frame; a feeding chute; a vibration exciter mounted on the beam fixed to the frame. The beam is made in the form of a resilient construction, the stiffness of which together with the stiffness of the dampers in a direction of a vector of the vibrations of the frame and the mass of the frame are defined by the ratio: C + Ca·n/M = ω² , where C is stiffness of the beam in respect to the frame, in H/m; Ca is stiffness of one damper, in H/m; n is a quantity of dampers, in pieces; M is the mass of the frame, in kg; ω is a resonance angular frequency of the frame vibrations, in radians/s. The beam is connected to the frame in its lower part by means of the vertical poles having a heightened stiffness in the direction of the vector of vibrations of the frame and made with a capability of being deformed in a horizontal direction together with the ends of the beam. At that the vibration exciter is connected to the mains supply through a frequency converter made with a capability of the electric current frequency change. The technical result of the invention is an increased vibration acceleration of the frame with a capability of its adjustment directly during the resonance screen shaker operation.

EFFECT: the invention ensures an increased vibration acceleration of the frame with a capability of its adjustment directly during the resonance screen shaker operation.

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Description

The invention relates to a device for cleaning drilling fluid and can be used in the oil and gas industries.

Known shale shaker according to A.S. USSR 848084, B 07 V 1/40, E 21 V 21/00, including a bed, a frame mounted by means of shock absorbers on a bed and equipped with a vibrator, two sieve sheets in series mounted on the frame, the discharge end of the first sieve sheet being located above the loading end of the second web installed obliquely in the direction of unloading materials at an angle of 5 °, the first sieve web installed obliquely in the direction of loading of materials with the possibility of changing the angle of inclination from 0 ° to 10 °, while the frame is equipped with an adjustment mechanism and the angle of inclination of the first screen cloth.

Known vibration sieve with linear vibrations SV1L, which has a similar device and is used in Russia in droves. This sieve is currently produced by Krasnodar Plant Neftemash OJSC and other manufacturers in accordance with TU 39 - 0147001 - 145 - 96 (see also NPO Product Catalog, Tekhoil, M., 2003). In accordance with the requirements of this TU sieve SV 1L provides an amplitude of vibration of the vibrating frame, equal to 2 mm (taking into account the tolerance, the amplitude can vary from 1.7 to 3.0 mm) with a frame vibration frequency of from 23 to 25 Hz.

A Swaco Mongoose double-acting vibrating screen is known, which comprises a bed, a frame mounted with shock absorbers on the bed and equipped with two vibrators, screen webs mounted on the frame, a mechanism for changing the frame angle, the supply chute, and the main directional vibrator consists of two circular vibrators vibrations, and the additional vibrator is a circular vibrator and is configured to turn on the vibrating screen during overload, the vibrators are mounted on a beam attached frame sidewalls (see Mongoose Shaker Dual -.. Motion Shaker Swaco, A Division of M -1 L.L.C., A Smith./ Schlumberger Company, Houston, Texas, 2001.).

It is known that Derrick vibrating sieve Flo - Line Cleaner 2000 is equipped with high-power vibrators (Super G vibrators with an integrated lubrication system), which made it possible to raise the frame vibration acceleration to 7.3 G (G - gravity acceleration, G = 9.81 m / s ² ) Due to this, this vibrating screen is currently the most powerful in terms of throughput (see prospectus "Flo - Line Cleaner 2000". Derrick Equipment Company, Oiltools (Europe) Limited, 2000).

Known vibrating sieve according to patent RU 2186635, 07 V 1/40, including a bed, a frame installed using shock absorbers and equipped with a vibrator, two sieve cloths sequentially fixed to the frame, the first of which is installed with the possibility of changing the angle of inclination from 0 ° to 10 ° and its discharge end is located above the loading end of the second sieve cloth, while the sieve is equipped with an upper tier consisting of a rigid frame sieve with a pre-stretched sieve cloth and is configured to adjust the frame to an angle from - 2 ° to + 10 °.

A common drawback of these analogues is that they operate in the forced oscillation mode in the frequency region far from resonance. As a result, the vibrating frames of these devices are exposed to a driving force that is many times greater than the driving force required when operating in the mode of maintaining resonant vibrations. This leads to a significant increase in the metal consumption of the frame, the power of the vibrators, obtaining, when using commercially available vibrators, low values of the frame acceleration - the main vibration parameter of the sieve, which determines the throughput and cleaning efficiency of the drilling fluid. In addition, an important disadvantage of these devices is the lack of the ability to control vibration acceleration of the frame without stopping the sieve and disassembling the nodes of the vibrators to rearrange the unbalances.

The objectives of the invention are: increasing the vibration acceleration of the frame with the possibility of its regulation directly during operation of the resonant sieve.

The solution of these problems is achieved by the fact that the resonant sieve includes a frame, a frame installed using shock absorbers, screen cloths mounted on the frame, a device for changing the angle of inclination of the frame, a feeding chute, a vibrator mounted on a beam attached to the frame, while the beam is made elastic, the stiffness of which relative to the frame, together with the stiffness of the shock absorbers in the direction of the oscillation vector of the frame and the mass of the frame are related by

where C is the stiffness of the beam relative to the frame, in N / m;

Ca - the stiffness of the shock absorber, in N / m;

n is the number of shock absorbers, in pcs .;

M is the mass of the frame, in kg;

ω is the resonant angular frequency of the frame oscillations, in rad / s;

moreover, the beam is attached to the frame in its lower part using vertical struts having increased rigidity in the direction of the frame oscillation vector and made with the possibility of deformation in the horizontal direction along with the ends of the beam, and the vibrator is connected to the mains through a frequency converter, configured to change the frequency electric current.

The application of the proposed set of essential features in a resonant sieve allows you to get a new technical result: to increase the vibration acceleration of the frame in comparison with analogs while reducing the metal consumption of the frame and the power of the vibrator, as well as to regulate the vibration acceleration of the frame directly during operation of the vibrating screen.

The analysis of the prior art in the field of vibrating devices for cleaning solutions showed that the set of essential features proposed in the resonant sieve is new, does not explicitly follow from the prior art and, therefore, the present invention is new and has an inventive step.

The invention is illustrated by drawings, while figure 1 shows a General view of a resonant sieve, figure 2 is a view A.

The resonant sieve contains a frame 1, a frame 2, which is mounted on the frame using shock absorbers 3 and is equipped with a vibrator 4. The screen webs are fixed on the frame 5. A device for changing the angle of inclination of the frame 6 and the feed chute 7 are mounted on the frame. The elastic beam 8 is connected to vertical posts 9. The vibrator windings are connected to the mains through a frequency converter 10.

Resonance sieve works as follows. When a supply voltage is applied to the windings of the vibrator, it excites the forced vibrations of the frame 2 on the elastic beam 8, which connects the frame through the posts 9 with a source of inertial force, i.e. with a vibrator 4. Using a frequency converter 10 change the frequency of the electric current and, therefore, the angular frequency of the driving force generated by the vibrator. By adjusting the angular frequency of the driving force to the resonant angular frequency of the oscillating system: bed 1 - shock absorbers 3 - frame 2 - vertical struts 9 - elastic beam 8 - vibrator 4, select the amplitude of the driving force at which the required maximum value of vibration acceleration of the frame is achieved. The vibrator is tuned to the selected value of the amplitude of the driving force. This completes the preparation of the resonance sieve for operation. When working by changing the angular frequency of the driving force in the frequency region of the ascending part of the resonance curve, the resonant sieve is adjusted to the required oscillation mode in accordance with the characteristics of the drilling fluid supplied to the sieve sheets. At the same time, it is taken into account that with an increase in the mass of the drilling fluid that lingers on the sieve sheets (due to an increase in viscosity or flow rate of the mud), the resonant angular frequency of the oscillatory system of the resonant sieve decreases slightly, which, when adjusting the angular frequency of the driving force on the ascending part of the resonance curve, provides automatic gain fluctuations.

This resonant sieve allows you to increase the vibration acceleration of the frame in comparison with analogues while reducing its metal consumption and reducing the power of the vibrator through the use of the effect of resonant amplification of vibrations, and also provides the ability to control the vibration acceleration of the frame directly during the operation of the sieve.

Применительно к этой задаче сравним данные для вибросита СВ1Л (при условной его модернизации) и для вибросита резонансного. Номинальное значение амплитуды колебаний в соответствии с ТУ на вибросито СВ1Л составляет 2 мм, что при частоте колебаний f=24 Гц дает виброускорение

Такое виброускорение рамы создают два вибратора мощностью по 1,5 кВт каждый. Суммарная синхронная вынуждающая сила вибраторов составляет 2×25=50 кН. Для условной модернизации вибросита СВ1Л примем (в запас достоинств резонансного сита) следующие допущения: а) повышение виброускорения рамы вибросита СВ1Л будет осуществлено за счет применения более совершенного вибратора, который будет развивать большую вынуждающую силу без увеличения массы вибратора; б) прочность рамы при повышении динамических нагрузок будет обеспечена без увеличения массы рамы за счет применения более рациональных конструкторских решений. Эти допущения позволяют оставить в расчетах полную массу рамы без изменений (M₁=1030 кг), включая массу собственно рамы (590 кг), балки для крепления мотор-вибраторов (190 кг) и двух мотор-вибраторов (2×125=250 кг). Величину вынуждающей силы P₁ определим по формуле

. Таким образом, для повышения виброускорения рамы на вибросите СВ1Л от 4,6 G до 10 G требуется увеличить вынуждающую силу с 50 кН до 101 кН, т.е. в 2 раза. Такое значительное увеличение вынуждающей силы не может обеспечить даже самый мощный мотор-вибратор из числа выпускаемых специализированным предприятием по выпуску мотор-вибраторов - ОАО "Ярославский завод "Красный маяк" (максимальное значение вынуждающей силы, развиваемой вибраторами этого завода, составляет 40 кН).Example 1. We determine the magnitude of the driving force that must be applied to the frame to obtain vibrations with vibration acceleration that exceeds the level achieved in modern vibrating screens (7.3 G in Derrick vibrating screens). We accept for perspective developments, taking into account the possible improvement of sieve cloths, vibration acceleration of the frame

In relation to this problem, we compare the data for the CB1L vibrating screen (with conditional modernization) and for the resonant vibrating screen. The nominal value of the oscillation amplitude in accordance with the technical specifications on the CB1L vibrating screen is 2 mm, which gives vibration acceleration at an oscillation frequency f = 24 Hz

Such vibration acceleration of the frame is created by two vibrators with a power of 1.5 kW each. The total synchronous driving force of the vibrators is 2 × 25 = 50 kN. For the conditional modernization of the CB1L vibrating screen, we will accept (in reserve of the advantages of the resonant screen) the following assumptions: a) the vibration acceleration of the CB1L vibrating screen frame will be increased by using a more advanced vibrator, which will develop a greater driving force without increasing the mass of the vibrator; b) the strength of the frame with increasing dynamic loads will be ensured without increasing the mass of the frame through the use of more rational design solutions. These assumptions allow us to leave the total weight of the frame unchanged in the calculations (M ₁ = 1030 kg), including the mass of the frame itself (590 kg), beams for attaching motor vibrators (190 kg) and two motor vibrators (2 × 125 = 250 kg ) The magnitude of the driving force P _{1 is} determined by the formula

. Thus, to increase the vibration acceleration of the frame on the CB1L vibrating screen from 4.6 G to 10 G, it is necessary to increase the driving force from 50 kN to 101 kN, i.e. 2 times. Such a significant increase in the driving force cannot be provided even by the most powerful motor-vibrator from the number of produced by the specialized enterprise for the production of motor-vibrators - JSC "Yaroslavl Plant" Red Beacon "(the maximum value of the driving force developed by the vibrators of this plant is 40 kN).

. Эксперименты показали, что уже при вынуждающей силе, равной 11 кН, виброускорение рамы достигает 10 G. Таким образом, коэффициент резонансного уменьшения вынуждающей силы составил К_р=78,5кН:11кН=7,1. Это значение в первом приближении, достаточном для практических расчетов, можно сравнить с диапазоном изменения динамического коэффициента μ увеличения амплитуды колебаний при резонансе. Динамический коэффициент μ определим по формуле (см. стр. 403 в книге: Снитко Н.К. Строительная механика. Учебник для ВТУЗов. Изд. 2-е, доп. М., "Высшая школа", 1972)On a resonant sieve, the mass of the frame is M = 800 kg and includes: the mass of the frame itself (590 kg), the mass of elements for tightening the frame structure (80 kg), the mass of the vibrator together with the spring structures and attachment points to the frame (130 kg). The estimated required driving force to obtain forced oscillations is

. The experiments showed that even with a driving force equal to 11 kN, the vibration acceleration of the frame reaches 10 G. Thus, the coefficient of resonant reduction of the driving force was K _p = 78.5 kN: 11 kN = 7.1. This value, in a first approximation, sufficient for practical calculations, can be compared with the range of variation of the dynamic coefficient μ of the increase in the amplitude of the oscillations at resonance. The dynamic coefficient μ is determined by the formula (see page 403 in the book: Snitko NK Structural Mechanics. A textbook for technical colleges. 2nd ed., Add. M., "Higher School", 1972)

where ε = K · ω is the damping coefficient of oscillations;

K is the coefficient determined experimentally for this design.

For the metal structures used in construction, it was experimentally established that K = 0.02 ... 0.08 (see p. 403 of the book by N. N. Snitko. Structural Mechanics. Textbook for technical colleges. 2nd ed., Add. M ., "Higher School", 1972). Based on these data, according to the indicated formula, we find that the dynamic coefficient μ ranges from 6.25 to 25. Thus, the value of the resonant reduction coefficient of the driving force K _p = 7.1 obtained for the resonant sieve is consistent with the range of variation of μ = 6, 25 ... 25.

Findings:

1) the possibility of obtaining vibrations in vibrating screens with increased vibration acceleration of the frame (for example, 10 G) by increasing the driving force when operating in forced vibrations (by analogy with the known vibrating screens) is limited by the power of the produced vibrators, as well as by feasibility studies, since the specific gravity the mass of the vibrators with their mounting beam in the total mass of the frame is too large even with vibration acceleration of 4.6 G and is (440 kg: 1030 kg) × 100% = 42.7%;

2) the resonant sieve provides oscillations with a record value of vibration acceleration of the 10G frame without increasing the mass and power of the vibrator while reducing the frame mass by 22% compared to the conventionally upgraded analogue SV1L and with a significant decrease in the power of the vibrator, the driving force decreases by 9 times.

Example 2. On an experimental sample of a resonant sieve, by changing the frequency of the electric current at the output of the frequency converter, the angular frequency of the driving force was changed (the resonant value of the angular frequency was ω = 314 rad / s). At the same time, the possibility of changing the vibration acceleration of the frame directly during the operation of the sieve in practically necessary limits (from 4 to 10 G) was confirmed. This opens up the possibility of a significant increase in the resource of sieve cloths. The practice of operating well-known vibrating screens has shown that the possibility of changing vibrations advertised by manufacturers of vibrating screens by changing the position of the unbalances on the vibrators is not really used. The reason is that to perform such an operation, it is necessary to stop the drilling fluid cleaning process for a sufficiently long time. This leads to the fact that the vibrating screens are operated in the tuning mode for maximum vibration acceleration without taking into account the factor of change in the properties of the drilling fluid with increasing drilling depth, as well as with targeted adjustment of its properties. As a result, the resource of sieve cloths is significantly reduced.

Conclusion: the above examples show that the present invention is industrially applicable.

Claims (1)

A resonant sieve, including a bed, a frame installed using shock absorbers, screen cloths mounted on the frame, a device for changing the angle of the frame, a feeding chute, a vibrator mounted on a beam attached to the frame, the beam being elastic, the rigidity of which relative to the frame along with the stiffness of the shock absorbers in the direction of the oscillation vector of the frame and the mass of the frame are related by the ratio

where C is the stiffness of the beam relative to the frame, N / m; Ca - the stiffness of the shock absorber, N / m; n is the number of shock absorbers, pcs; M is the mass of the frame, kg; ω is the resonant angular frequency of the frame, rad / s, moreover, the beam is attached to the frame in its lower part using vertical struts having increased rigidity in the direction of the frame oscillation vector and made with the possibility of deformation in the horizontal direction along with the ends of the beam, and the vibrator is connected to the mains through a frequency converter, configured to change the frequency electric current.

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