RU2018909C1 - Gas pressure regulator - Google Patents

Abstract

FIELD: automatic control. SUBSTANCE: regulator has housing 1 with inlet cavity 2 and outlet cavity 3 separated by first valve 5, first sensitive element in the form of stepped piston 6 and second sensitive element in the form of piston 10 coupled with second and third valves 15 and 19 responsive to an output pressure and providing correction for output pressure and precise control by filling/emptying the cavities. The regulator is characterized by the relationship of structural parameters to provide minimum possible output pressure which can be calculated from the expression given in the invention description. EFFECT: widened output pressure range towards lower values. 1 dwg

Description

 The invention relates to automatic regulation and can be used in pneumatic systems for various purposes.

 A gas pressure regulator is known, comprising a housing with a first valve located between the inlet and outlet cavities, a first sensing element in the form of a step piston installed in the housing, the lower stage of which is connected to the first valve and forms the first cavity with the larger stage and housing, which is communicated through the throttle with the atmosphere. There is a second sensing element in the form of a piston loaded with a task spring, and a second cavity, which is in communication with the outlet cavity and through the second valve with the first cavity. Moreover, the piston is placed in a sleeve installed in the housing between the piston and the larger stage of the staged piston and provided with a seat for the second valve, which is located in the piston, the second cavity is formed by the piston and the sleeve, in which the seat of the third valve is placed in the sleeve, which forms with the larger stage step piston third cavity. In this case, the second and third cavities are communicated through the third valve, and in the initial position, the sleeve is contacted with the piston and a large step of the stepped piston, the third valve is squeezed from its seat by the piston, and the connection of the third valve with its seat in their contact position is made with guaranteed leakage.

 The essential features of the prototype listed above provide increased accuracy of the regulator, but there is uncertainty in the lower value of the output pressure, and at the same time, in establishing the range of output pressures.

≥ 1,, где Δ F - эффективная кольцевая площадь ступенчатого поршня, воспринимающая давление в третьей полости;
F_в - эффективная площадь втулки,

≥ 1,, где h_и - отжатие первого клапана в исходном положении;
h_кр - критическое (минимально допустимое) отжатие первого клапана, при котором с учетом сопротивления выходной магистрали устанавливается критическое выходное давление Р_кр, достаточное воздействием на площадь Δ F для поддер- жания h_кр, и

(T_кр+ KX)

≥ 1,, где Т_н и Т_кр - усилия на первом клапане соответственно в расходном регулируемом режиме и при отжатии клапана на величину h_кр;
К - жесткость пружины задания;
Х - суммарное сжатие пружины задания при перемещении втулки от положения, соответствующего h_кр, до упора в корпус и второго чувствительного элемента из положения упора во втулку до положения, соответствующего началу перемещения второго клапана;
F₂ - площадь второго чувствительного элемента, причем меньшие значения соотношений соответствуют меньшим значениям выходного давления, а само минимальное значение выходного давления Р_н.мин определяется по формуле
P_н.мин=

..The technical result of the invention is the expansion of the range of output pressures towards lower values by proposing the ratios of the structural parameters of the regulator, which determine the minimum output pressures, and the formula that determines the value of the minimum output pressure itself, i.e., the set of features in the first paragraph of the formula is supplemented by the following new significant features . There are relations

≥ 1 ,, where Δ F is the effective annular area of the stepped piston perceiving pressure in the third cavity;
F _in - the effective area of the sleeve,

≥ 1 ,, where h _and are the depressions of the first valve in the initial position;
h _cr is the critical (minimum allowable) squeezing of the first valve, in which, taking into account the resistance of the output line, a critical output pressure P _{cr is set} , sufficient to influence the area Δ F to maintain h _cr , and

(T _cr + KX)

≥ 1 ,, where T _n and T _cr are the forces on the first valve, respectively, in the flow controlled mode and when the valve is depressed by the value of h _cr ;
K is the spring stiffness of the task;
X is the total compression of the job spring when moving the sleeve from the position corresponding to h _cr , until it stops in the housing and the second sensing element from the stop position in the sleeve to the position corresponding to the start of movement of the second valve;
F ₂ - the area of the second sensitive element, and lower values of the ratios correspond to lower values of the outlet pressure, and the minimum value of the outlet pressure P _n.min is determined by the formula
P _n.min =

..

 Derivation of the ratio of parameters and the formula for the minimum output pressure.

 Friction forces during output are not released. They are supposed to be taken into account with the corresponding signs as components of the forces under consideration.

Let us agree that the process of the regulator going from the initial position to the control mode with the outlet adjustment pressure P _{n is} carried out with the resistance of the outlet line (for example, when the discharge washer is installed), which ensures the maximum allowable gas flow.

 The technical result of the invention is the expansion of the range of output pressures towards its lower values.

In the initial position of the regulator (the regulator is configured, but the inlet pressure is not supplied) there must be some minimum necessary R _{and the} reference springs, at which the first valve can be depressed by the value of h _and provided that T _and = R _and.
There is a certain minimum allowable value of squeezing h _cr (critical) at which, when the output pressure is applied to the output cavity, there may be some minimum pressure P _cr , capable of retaining the stepped piston and, with it, the first valve with squeezing, the effective pressure of the stepped piston ΔF h _cr The value of h _cr correspond and T _cr = R _cr. h _cr calculated according to well-known formulas taking into account the gas flow.

≥ 1. (1)
Вторым условием выхода регулятора на режим регулирования с давлением Р_н является силовое воздействие втулки на ступенчатый поршень, по крайней мере, до возрастания давления до значения Р_кр, т.е. P_кр˙ΔF≥P_крF_в или

≥ 1 (2) где F_в - эффективная площадь втулки.Thus, the first condition for the implementation of the process of the regulator entering the control mode is the ratio

≥ 1. (1)
The second condition for the regulator to enter the control mode with pressure P _n is the force action of the sleeve on the step piston, at least until the pressure increases to the value of P _cr , i.e. P _cr ˙ΔF≥P _cr F _in or

≥ 1 (2) where F _in is the effective area of the sleeve.

Moreover, from the operating conditions of the regulator (the sleeve at P _n must move all the way to the housing) it should be F _in ≥F ₂ (3) where F ₂ is the area of the second sensitive element.

Further movement of the first valve by
Δh = h _n - h _cr , where h _n is the valve stroke corresponding to the pressure P _n and the force on the valve T _n , is carried out with an increase in the force on the first valve by ΔT = T _n - T _cr .

The output pressure in this case increases by ΔР = P _n - P _cr .

,, где R_н - усилие пружины задания при P_н;
P_кр=

,то выражение(4) можно записать

-

F ≥ ΔT.. (5)
Так как R_н = R_кр + К (Х_в + Х₂), где Х_в - перемещение втулки из положения, соответствующего h_кр, до упора в корпус (в направлении сжатия пружины задания);
Х₂ - перемещение второго чувствительного элемента из положения упора во втулку в положение, соответствующее началу перемещения второго клапана;
R_кр = Т_кр, то при обозначении Х_в + Х₂ = Х, выражение (5) принимает вид

-

F ≥ ΔT
или
(T_кр+KX)

- T_кр≥ ΔT ..Assuming a linear dependence of Δ P and Δ T on Δ h, write down the condition of sufficient force on the additional pressure ΔP to depress the first valve by Δh, i.e. to the effort T _n :
ΔP˙ΔF≥ΔT, (4)
Since ΔP = P _n - P _cr and P _n =

,, where R _n - the force of the reference spring at P _n ;
P _cr =

, then expression (4) can be written

-

F ≥ ΔT .. (5)
Since R _n = R _cr + K (X _in + X ₂ ), where X _in - the movement of the sleeve from the position corresponding to h _cr , until it stops in the housing (in the compression direction of the job spring);
X ₂ - the movement of the second sensing element from the stop position into the sleeve to the position corresponding to the beginning of the movement of the second valve;
R _cr = T _cr , then when designating X _in + X ₂ = X, expression (5) takes the form

-

F ≥ ΔT
or
(T _cr + KX)

- T _cr ≥ ΔT ..

(T_кр+KX)

≥ 1. (6)
Соотношение (3) - общее условие для любого диапазона выходных давлений. Соотношения (1), (2) и (6) необходимо учитывать при проектировании, решая задачу расширения диапазона выходных давлений в сторону его низших значений.Given Δ T + T _cr = T _n finally write

(T _cr + KX)

≥ 1. (6)
Relation (3) is a general condition for any range of output pressures. Relations (1), (2) and (6) must be taken into account when designing, solving the problem of expanding the range of output pressures towards its lower values.

From relation (1) it follows that for h _and > h _cr , the first valve is pressed in the initial position with excess due to the excessive force of the task spring, which in an adjustable mode gives R _n and P _n more than the minimum possible. The equal sign in the ratio corresponds to the minimum P _n .

From relation (2) it follows that when the pressure piston P _cr reaches the output and third cavities, the step piston, which is able to move without the force of the sleeve, continues to experience this effect at F _at <Δ F, i.e., the force of the driving spring and P _n enlarged. The equal sign in this ratio also corresponds to the minimum P _n .

Expression (4), from which relation (6) is derived, has a factor ΔР on the left side. Its decrease (P _n = P _cr + Δ P) corresponds to a decrease in P _n , and the equal sign in relations (4) and (6) corresponds to the minimum P _n .

 Thus, lower values of the relations (1), (2) and (6) corresponds to a larger technical result.

It is advisable to begin designing with the assignment of force on the first valve, based on the required sealing force, possibly taking into account the dynamics, determining Δ h _cr and choosing F ₂ . Further, taking into account relations (2), (3) and (6), F _c , ΔF are assigned.

The very minimum value of P _n.min is determined as follows.

Minimum possible force R _n compression springs
R _n.min = T _cr + KX.

или
P_н.мин=

.. (7)
Используя соотношения (1), (2) и (6), можно расширять диапазон выходных давлений регулятора, а по формуле (7) определить минимально возможное давление настройки.Minimum setting pressure
P _n.min =

or
P _n.min =

.. (7)
Using relations (1), (2) and (6), it is possible to expand the range of output pressures of the regulator, and using formula (7) to determine the minimum possible setting pressure.

 The gas pressure regulator is shown schematically in the drawing.

 The regulator comprises a housing 1 with an inlet 2 and an outlet 3 cavities separated by a seat 4 with a first valve 5, the first sensing element in the form of a step piston 6, a smaller stage of which is connected through the rod 7 to the first valve and forms a first cavity 8 with a larger stage and body, connected through the throttle 9 to the atmosphere, the second sensing element in the form of a piston 10 placed in the sleeve 11, forming with it a second cavity 12 and loaded with a task spring 13. The second cavity 12 is communicated through the seat 14 and the second valve 15 located in the piston 10, through the channel 16 in the adapter 17 with the first cavity 8. The sleeve 11 forms a third cavity 18 with a larger piston stage 6, with which the second is connected through the third valve 19 with the seat 20 cavity 12. The channel 21 of the second cavity 12 is in communication with the output cavity 3. The contact of the valve 19 with the seat 20 is made with guaranteed leakage.

The area F _{in the} sleeve 11 is shown conditionally. To determine the effective area F _in should take into account the area of the adapter 17.

 The regulator operates as follows.

In the initial position, the sleeve 11 is pressed against the piston 6 by the setting spring 13 through the piston 10. The first valve 5 is pressed from the seat 4 by the piston 6 through the stem 7 in a particular case by the value of h _cr . The valve 19 is squeezed from the seat 20 by the piston 10, and the valve 15 is pressed against the seat 14 by a spring with a clearance of X ₂ relative to the hard stop in the piston 10. The sleeve 11 has a stroke X _in the direction of compression of the spring 13 of the job.

When the medium is supplied into the inlet cavity 2 and with the corresponding resistance of the outlet line and valve release (h _cr ) in the outlet 3, second 12, and third 18 cavities, the pressure begins to increase to a certain critical value P _cr . At this pressure, the piston 6 can, when the first cavity 8 is empty, already without the influence of the sleeve 11 move, additionally pressing the first valve 5. The pressure in the cavities 3, 12 and 18 increases to the required setting pressure P _n , at which the sleeve 11 and the piston 10 move the values of X _in and X _2, respectively, and depending on the magnitude of the pressure P _n may open the saddle 14 and some filling of the first cavity 8.

With the initial extraction of the first valve 5 by the value of h _cr , with ratios (1), (2) and (6) equal to unity, and at minimum X _in and X _{2, the} output pressure P _n will be the minimum possible.

 In steady-state operating modes, in the general case, the outlet pressure is kept stable due to the reaction to the outlet pressure of the pistons 6 and 10, possible replenishment and emptying of the first cavity 8, and automatic movement of the first valve 5. Some changes in the outlet pressure in the steady-state process are also monitored in the third cavity due to the guaranteed leakage of the seat seal 20 by the valve 19.

Claims (1)

A GAS PRESSURE REGULATOR, comprising a housing with a first valve located between the inlet and outlet cavities, a first sensing element in the form of a step piston installed in the housing, the lower stage of which is connected to the first valve and forms the first cavity, which is connected through the throttle to the atmosphere , a second sensing element in the form of a piston loaded with a task spring, and a second cavity that is in communication with the output cavity and through the second valve with the first cavity, and the piston still in the sleeve installed in the housing between the piston and the larger stage of the staged piston and provided with a seat for the second valve, which is located in the piston, the second cavity is formed by the piston and the sleeve, which is the seat of the third valve located in the sleeve, which forms with the larger stage of the staged piston the third cavity, while the second and third cavities are communicated through the third valve, and in the initial position, the sleeve is in contact with the piston and the larger step of the stepped piston, the third valve is pushed away from its seat a screw, and the connection of the third valve with its seat in their contact position is made with guaranteed leakage, characterized in that the design parameters are assigned in accordance with the ratios
ΔF / F _at ≥ 1,
where ΔF is the effective area of the stepped piston, perceiving pressure in the third cavity;
F _in - the effective area of the sleeve,
h _and / h _kp ≥ 1,
where h _and - squeeze the first valve in its original position;
h _cr - critical (minimum allowable) squeezing of the first valve, in which, taking into account the resistance of the output line, a critical output pressure P _{cr is established} , sufficient to influence the area ΔF to maintain h _cr ;

(T _cr + KX)

≥ 1 ,,
where T _n , T _cr - the efforts on the first valve, respectively, in the flow controlled mode and when the valve is depressed by the value of h _cr ;
K is the spring stiffness of the task; X is the total compression of the job spring when moving the sleeve from the position corresponding to h _cr to the stop in the housing and the second sensing element from the stop position in the sleeve to the position corresponding to the start of movement of the second valve;
F ₂ - the area of the second sensitive element,
moreover, lower values of the ratios correspond to lower values of the outlet pressure, and the minimum value of the outlet pressure P _{nmin itself} is determined by the formula
P _{n min} = (T _cr + K˙X) / F ₂ .