CN105625982A - Method for designing SCM (Single Chip Microcomputer) single-charged low-pressure reversing valve for deep sea underwater Christmas tree - Google Patents

Abstract

The invention provides a method for designing an SCM (Single Chip Microcomputer) single-charged low-pressure reversing valve for a deep sea underwater Christmas tree. Particularly, the design method comprises four steps of: according to an actual use environment, determining a design scheme; checking and calculating geometric dimensioning; checking and calculating an operation stress of a valve body; reexamining and checking. The design method provided by the invention is reasonable, and has high calculation efficiency and accuracy; a design value is closer to an actual use value; reliability of the design work of the single-charged low-pressure reversing valve of an electrohydraulic control valve bank for the deep sea underwater Christmas tree is effectively improved so as to facilitate improving stability and reliability of the valve body in the actual use.

Description

Design method of SCM single-electric low-voltage reversing valve of deep-sea underwater Christmas tree

Technical Field

The invention relates to a design method of an SCM single-electric low-voltage reversing valve of a deep-sea underwater Christmas tree, in particular to a design method of an SCM single-electric low-voltage reversing valve of a deep-sea underwater Christmas tree.

Background

At present, in the development process of deep sea oil and gas resources, deep sea underwater Christmas tree equipment is widely applied and plays a vital role in the development of deep sea oil and gas resources, but in practical use, the current single-electric low-voltage reversing valve used on the deep sea Christmas tree is designed and prepared by transforming the traditional fresh water underwater single-electric low-voltage reversing valve or shallow sea underwater single-electric low-voltage reversing valve through an empirical formula, although the requirement of deep sea environment operation can be met to a certain extent, the single-electric low-voltage reversing valve for the deep sea Christmas tree, which is designed and prepared in the mode, has larger errors between the operation technical parameters and the practical use environment, so that the single-electric low-voltage reversing valve has serious insufficient operation stability in the deep sea environment, meanwhile, the traditional experience in the design process of the single-electric low-voltage reversing valve has serious insufficient calculation precision on one hand, on the other hand, the calculation efficiency is relatively low, and meanwhile, effective checking and verification cannot be performed on the design structure obtained through calculation, so that great trouble is caused to the design work, and therefore, aiming at the current situation, a design method of the single-electric low-voltage reversing valve, which is strong in universality, simple and easy to implement, is urgently required to be developed to meet the requirement of actual use.

Disclosure of Invention

The invention aims to provide a design method of an SCM single-electric low-voltage reversing valve of a deep-sea underwater Christmas tree.

In order to achieve the purpose, the invention provides the following technical scheme:

a design method of an SCM single-electric low-voltage reversing valve of a deep-sea underwater Christmas tree comprises the following steps:

firstly, determining a design scheme according to an actual use environment, preliminarily determining an effective working environment adaptation range of a valve body, various operation technical indexes of the valve body and a basic mechanical structure of the valve body according to the actual deep sea underwater operation environment condition of the valve body and the working medium condition;

secondly, checking and calculating the geometric dimension, namely checking and calculating the geometric dimension of the valve body according to the technical parameters of the valve body and the basic mechanical structure set in the first step, wherein the checking and calculating of the diameters of an oil inlet and an oil outlet, the diameter of an inner hole and a push rod of a valve seat of a main ball valve, the minimum opening of a valve port of the main valve and the stroke of the main valve core are required;

thirdly, checking and calculating the running stress of the valve body, and according to the running environment and the technical parameters set in the first step and the specific size of the mechanical structure obtained by calculation of the second part, calculating and checking each stress condition in the running condition of the valve body, wherein the friction resistance, the motion resistance, the hydraulic clamping force, the steady hydraulic force, the valve core acting force and the return spring elastic force need to be checked and calculated;

fourthly, designing a main valve, and calculating the diameter of the control piston and the return spring according to the data obtained in the previous three steps;

and fifthly, reviewing and checking, namely selecting at least one group of data according to the set parameter range of the first step, bringing the selected data into the specific data obtained by the calculation of the second step and the third step, and then carrying out the reviewing and checking calculation by combining the actual operation condition of the valve body.

Furthermore, the fifth step needs to perform checking calculation on at least two groups of different parameters.

The design method is reasonable, the calculation efficiency and the calculation precision are high, the design value is closer to the actual use value, and the reliability of the design work of the single-electric low-pressure reversing valve of the electro-hydraulic control valve group of the deep-sea underwater Christmas tree is effectively improved, so that the stability and the reliability of the valve body in the actual use are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a flow chart of the method of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

as shown in fig. 1, the design method of the SCM single-electric low-voltage reversing valve of the deep-sea underwater Christmas tree comprises the following steps:

the method comprises the following steps of firstly, determining a design scheme according to an actual use environment, preliminarily determining an effective working environment adaptation range of a valve body, establishing various operation technical indexes of the valve body and a basic mechanical structure of the valve body according to the deep sea underwater operation actual environment condition of the valve body and the working medium condition:

the working environment is as follows:

the hydraulic valves are all arranged in a sealed container at the depth of 3000 m of water in the ocean

1.2 temperature requirement:

1) storage temperature range: -18 ℃ - +50 ℃;

2) working temperature range: -5 ℃ to +40 ℃.

3) Working medium: water-based fluids, such as HW 443.

The control principle is as follows: when the oil circuit is normal, the electromagnetic valve can control the opening, locking and closing of the valve when the oil supply pressure P is below 56.9Mpa and PP is in the range of 13.8-37.9 Mp, and provides the hydraulic oil with the working pressure of 11.3-56.9 Mpa for the actuator, wherein the commonly used state is that: p is 56.9Mpa, PP is 34.5Mpa, and the actuator is provided with hydraulic oil with the working pressure of 11.3-56.9 Mpa;

and secondly, checking and calculating the geometric dimension, wherein the geometric dimension of the valve body is checked and calculated according to the technical parameters of the valve body and the basic mechanical structure set in the first step, wherein the diameters of an oil inlet and an oil outlet, the diameter of an inner hole and a push rod of a valve seat of the main ball valve, the minimum opening of a valve port of the main valve and the stroke of the main valve core need to be checked and calculated:

the oil outlet diameter calculation formula:

wherein: d-diameter of oil port

Q- -rated flow (l/min);

v-oil outlet flow velocity of the diameter d of the oil inlet and the oil outlet, the larger the pressure is, the higher the velocity is, and therefore, 10m/s is selected:

$d\≥\sqrt{\frac{4Q}{\mathrm{\π}v}}=\sqrt{\frac{4\×16.8\×{\mathrm{10}}^{\mathrm{-3}}}{\mathrm{\π}\×\mathrm{10}\×\mathrm{60}}}\×\mathrm{1000=5}\mathrm{.97}mm$

rounding to obtain a circle d equal to 6 mm;

the calculation formula of the diameter of the inner hole of the valve seat of the main ball valve, the diameter of the push rod and the diameter of the steel ball is as follows:

d1≥1/2D1

the flow formula of the annular channel between the valve port and the push rod is

$Q=\frac{\mathrm{\π}}{4}\[{D_1}^2-{d_1}^2\]V$

The flow Q of the above formula is brought in by the rated flow, and the oil flow velocity V in the annular channel is caused byThen

$Q\≤\frac{\mathrm{\π}}{4}\[{D_1}^2-{\left(\frac{D_1}{2}\right)}^2\]V$

$D_1\≥\sqrt{\frac{16Q}{3\mathrm{\π}V}}=6.89mm$

Rounding to obtain round piece with D1 being 5mm, D1 being 3.5mm,

the diameter of the steel ball is 8 mm;

wherein: d 1-push rod diameter

D1 diameter of inner hole of main ball valve seat with diameter of push rod

v-oil flow velocity in annular passage

The minimum opening calculation formula of the main valve port is as follows:

the formula for calculating the flow through the valve port is:

$Q=C_{d}A\sqrt{2\mathrm{\Δ}p/\mathrm{\ρ}}$

in the formula:

q-liquid flow through the valve port (m 3/s);

a-valve port flow area (m 2);

Δ p — differential pressure across the valve port (Pa);

p-fluid density (kg/m 3);

cd-is valve port flow coefficient;

the valve port flow area A is calculated by the formula:

$A={\mathrm{\πDhX}}_1(1+X_1/2h)/\sqrt{{(D/2)}^2+{(h+X_1)}^2};$

wherein, $h=\sqrt{R^2-\frac{D^2}{4}};$

when in use $x_1<<\frac{d}{2},$ X₁When the ratio is smaller than R, the crystal, $\sqrt{{(D/2)}^2+{(h+X_1)}^2}\&ap;R,\frac{X_1}{2h}\&ap;0,$

the above formula can be changed into

$A=\mathrm{\&pi;}D\sqrt{R^2-\frac{D^2}{4}}{X}_1/R;$

The opening minimum opening formula of the valve can be solved as follows:

$X_1=\frac{QR}{C_d\mathrm{\&pi;}D\sqrt{\frac{2\mathrm{\&Delta;}P(R^2-\frac{D^2}{4})}{\mathrm{\&rho;}}}};$

the value of Delta P is 1MPa, and Cd is 1, so

X1＝0.38mm；

The main valve core stroke calculation formula:

the stroke S of the valve core is required to be larger than X1: s > X1, taking

S＝1mm；

Wherein: s is the stroke of the valve core;

x1-minimum opening of main valve port;

and thirdly, checking and calculating the running stress of the valve body, and according to the running environment and the technical parameters set in the first step and the specific size of the mechanical structure obtained by calculation of the second part, calculating and checking each stress condition in the running condition of the valve body, wherein the friction resistance, the motion resistance, the hydraulic clamping force, the steady hydraulic force, the valve core acting force and the return spring elastic force need to be checked and calculated:

the friction resistance calculation formula is as follows:

since bt is 0.55 d;

d0 is the diameter of the end face of the O-ring. It is assumed that the O-ring and the control piston only move in contact under the action of Pb, and the contact width is unchanged.

The clamping force of the O-shaped ring on the control piston is

$N=\frac{P_d}{2}{\mathrm{\&pi;d}}_t{b}_t;$

Then

F_m＝fN＝0.275πfP_bd_td₀

Wherein: f_m-a frictional resistance;

f is friction coefficient, and f can be 0.1;

dt-piston rod diameter;

d 0-O-ring end diameter;

pb-allowable back pressure;

therefore, it is not only easy to use

F_m＝0.0864P_bd_td₀

If there are 5O-rings on the main valve core, for safety, the calculation is performed according to the maximum friction force of each O-ring, i.e. the maximum back pressure, so the respective friction force is:

opening control piston

The maximum back pressure of the piston is controlled to Pb2 bar 569bar, the section diameter d02 of the O-shaped ring is 1.8mm, and the diameter dt2 of the piston

F_m2＝0.0864P_b2d_t2d₀₂＝4916d_t2＝7.08N；

The motion resistance calculation formula is as follows:

$F_V=\frac{\mathrm{\&pi;}DLV\mathrm{\&mu;}}{\mathrm{\&Delta;}r}$

wherein: f_v-resistance to movement;

d-control piston diameter;

l is the contact length of the control piston and the valve body hole;

v is the motion speed of the valve core, and can be replaced by the average speed when the action time of the valve core is 0.01 s; so that the valve core $V=\frac{s}{\&lsqb;t_{dh}\&rsqb;}=\frac{0.002}{0.01}=0.2m/s;$

Mu-dynamic viscosity of oil, kinematic viscosity of HW443 is 1.9mm 2/s;

delta r is the unilateral fit clearance between the valve core and the valve body hole, and is 0.05 mm.

Therefore, it is not only easy to use

$F_{V1}=\frac{{\mathrm{\&pi;d}}_{t1}LV\mathrm{\&mu;}}{\mathrm{\&Delta;}r}=0.14d_{t1}$

Since the hydraulic oil viscosity is low and the fitting clearance of the valve is relatively large, the movement resistance is very small, so it is ignored in the calculation formula.

When the hydraulic clamping force is calculated, the hydraulic clamping force is generated because when fluid flows in a fit clearance between a valve core and a valve body of the hydraulic valve, because the valve core and a valve body hole have conicity and eccentricity, pressure distribution changes exist at different clearances in the circumferential direction, a radial unbalanced force is generated on the valve core, and meanwhile, because an O-shaped sealing ring is adopted for sealing between the valve core and the valve body, the leakage amount is almost zero, and the hydraulic clamping force is ignored in the design;

the steady state hydraulic calculation formula is as follows:

F_W＝C_dπDΔpsinα

meanwhile, due to the structure of the valve core, when the valve core is reversed, two ports are in an opening state, the liquid flow on one side is in a downward flow mode, the liquid flow on the other side is in an upward flow mode, but the steady-state hydrodynamic force applied to the valve core faces to one direction and is opposite to the liquid flow direction, so the steady-state hydrodynamic force of the two ball valves needs to be calculated in a calculation formula. The valve core is the same whether in the left position or the right position, and during calculation, only the steady-state hydrodynamic force of the valve core on one side is calculated, and the steady-state hydrodynamic force of the valve core needs to be calculated under two conditions, wherein one condition is a small opening, namely 1/3max, and the other condition is when the valve core is fully opened;

this gives the sum of the steady-state hydraulic forces:

∑F_W＝F_W1+F_W2＝C_dπDΔpsinα₁+C_dπD(S-)Δpsinα₂

in the formula:

cd is valve port flow coefficient, and Cd is 1;

d is the diameter of the valve port;

-the amount of opening of the valve;

delta p is the pressure difference (Pa) between two ends of the valve port, 1MPa is taken when the valve port is opened small, and 0.1MPa is taken when the valve port is opened large;

alpha is a liquid flow angle, alpha is 69 degrees when the opening is large, and alpha is 21 degrees when the opening is small;

due to the structure of the valve core, when the valve core is reversed, two ports are in an open state, one side of the valve core is in a downflow mode, and the other side of the valve core is in an upflow mode, but the steady-state hydrodynamic force applied to the valve core is in one direction and is opposite to the direction of the liquid flow, so that the steady-state hydrodynamic forces of the two ball valves need to be calculated in a calculation formula. And the valve core is the same whether in the left position or the right position, and only the steady state hydrodynamic force of the valve core on one side is calculated during calculation.

The steady-state hydrodynamic force calculation of the valve element requires calculation of the steady-state hydrodynamic force in two cases, one is a small opening, namely 1/3max, and the other is when the valve element is fully opened.

When the valve core is in a small opening, the steady state hydrodynamic force sum is as follows:

∑F_W＝F_W1+F_W2＝C_dπDΔpsinα₁+C_dπD(S-)Δpsinα₂

∑F_W＝4.8N

when the valve is fully open, S2 mm, the steady state hydrodynamic sum is

∑F_W＝C_dπDΔpsinα₁＝4.1N

Valve core acting force calculation formula:

the maximum working load of the spring can be calculated as follows

F_t2＞∑F_W+F_p1＝8N

∑F_W-steady state hydrodynamic forces on the spool;

F_p1hydraulic pressure on spool

Take Ft2 ═ 15N

The stiffness of the spring:

$K_1=\frac{F_{t2}-F_{t1}}{S}=2.5N/mm$

in the formula:

∑F_m-the sum of the frictional resistances;

F_p-the pressure generated by the spool;

F_t1spring minimum workload.

∑F_W-steady state hydrodynamic forces when the spool ring is open;

F_t2-small spring maximum working load;

k1-spring rate;

thus, the following steps are obtained:

opening control piston

When the control piston is started to open the valve core, the following conditions are required

F_{Opening 1}＞∑F_m+F_p+F_t1

F_{Opening 1}-valve core force in open state;

F_{opening 2}-closed state spool force;

∑F_m-the sum of the frictional resistances;

F_p-the pressure generated by the spool;

F_t1-small spring minimum work load;

when the valve core is in place, the following conditions are required:

F_{opening 2}＞∑F_W+F_p+F_t2-F_From；

Closing control piston

When the valve is closed, the closing piston pushes the main valve core away, and at the moment, the force and the friction force of the self-locking piston are required to be overcome, and steady-state hydraulic power is also required. P, R, C, the valve is in unloading state, the liquid in the self-locking piston loses pressure, the closing control piston can be closed with small force, so the force of the closing control piston at the time of starting closing the valve is only calculated.

The closing control piston is required to satisfy the following conditions

F_{Closing device}＞∑F_m+∑F_W+F_From-K(X_t+S)-F_p

The elastic force calculation formula of the return spring is as follows:

K₁(X_T+S)＝∑F_W1+∑F_m1+F_p1

in the formula:

∑F_w1-steady state hydrodynamic force of the spool at full opening of 569 bar;

∑F_m1-the sum of the frictional resistances of the spool at 569 bar;

F_p1-the liquid pressure to which the ball valve element is subjected at 569 bar;

when the valve core is in place, the following conditions need to be met, and because the valve core has a high action speed which is generally less than 0.01s, the acting force generated by the control piston needs to be calculated on the premise that the liquid in the control piston does not flow out in time for the reliability of the valve core.

KX_t＞F_{From 1}

When the valve core reaches the small opening position, the following conditions are met, and the acting force generated by the control piston needs to be calculated.

K(X_t+S-1/3_max)＞F_{From 1}+∑F_{W1 is small}+∑F_m1

∑F_{w1 is small}Steady-state hydrodynamic forces of the valve core at a small opening of 69 bar;

and fourthly, designing a main valve, calculating the diameter of the locking piston and the return spring, calculating the diameter of the control piston, calculating the return piston and calculating the return spring according to the data obtained in the previous three steps:

diameter of locking piston

When the locking piston is in a locking position, the left pilot valve and the right pilot valve are not opened, and the force of PP pressure acting on the control piston is zero. The piston is locked to enable the left ball to move rightwards, the push rod pushes the right ball away, the main valve is kept in an open state all the time, an oil inlet P is 69MPa, the back pressure is 0, and the valve core can be locked;

calculation of return spring

When the pressure of the port P is reduced to 27.8Mpa, the main valve is automatically closed,

valve port diameter D is 3.5mm

The hydraulic pressure P-265N received by valve port

The working position F of the return spring is 250N, and the initial pressure F is 200N

And fifthly, reviewing and checking, namely selecting at least one group of data according to the set parameter range of the first step, bringing the selected data into the specific data obtained by the calculation of the second step and the third step, and then carrying out the reviewing and checking calculation by combining the actual operation condition of the valve body.

In this embodiment, the fifth step needs to perform checking calculation on at least two different sets of parameters.

The design method is reasonable, the calculation efficiency and the calculation precision are high, the design value is closer to the actual use value, and the reliability of the design work of the single-electric low-pressure reversing valve of the electro-hydraulic control valve group of the deep-sea underwater Christmas tree is effectively improved, so that the stability and the reliability of the valve body in the actual use are improved.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (2)

1. A design method of an SCM single-electric low-voltage reversing valve of a deep-sea underwater Christmas tree is characterized by comprising the following steps: the design method of the SCM single-electric low-voltage reversing valve of the deep-sea underwater Christmas tree comprises the following steps:

firstly, determining a design scheme according to an actual use environment, preliminarily determining an effective working environment adaptation range of a valve body, various operation technical indexes of the valve body and a basic mechanical structure of the valve body according to the actual deep sea underwater operation environment condition of the valve body and the working medium condition;

secondly, checking and calculating the geometric dimension, namely checking and calculating the geometric dimension of the valve body according to the technical parameters of the valve body and the basic mechanical structure set in the first step, wherein the checking and calculating of the diameters of an oil inlet and an oil outlet, the diameter of an inner hole and a push rod of a valve seat of a main ball valve, the minimum opening of a valve port of the main valve and the stroke of the main valve core are required;

thirdly, checking and calculating the running stress of the valve body, and according to the running environment and the technical parameters set in the first step and the specific size of the mechanical structure obtained by calculation of the second part, calculating and checking each stress condition in the running condition of the valve body, wherein the friction resistance, the motion resistance, the hydraulic clamping force, the steady hydraulic force, the valve core acting force and the return spring elastic force need to be checked and calculated;

fourthly, designing a main valve, and calculating the diameter of the control piston and the return spring according to the data obtained in the previous three steps;

and fifthly, reviewing and checking, namely selecting at least one group of data according to the set parameter range of the first step, bringing the selected data into the specific data obtained by the calculation of the second step and the third step, and then carrying out the reviewing and checking calculation by combining the actual operation condition of the valve body.

2. The design method of the SCM single-electric low-voltage reversing valve of the deep-sea underwater Christmas tree according to claim 1, is characterized in that: and the fifth step needs to carry out checking calculation on at least two groups of different parameters.