Pressure Compensator (P)#

Pressure Compensator (P) block has 4 ports:

A and B are pneumatic ports through which gas flows through the network in question;
X and Y are pneumatic ports of a third-party pneumatic network. The characteristics of this network (for example, the dependence of the flow rate on the pressure drop on each element of the network or the network as a whole) are not included in the calculation of the main pneumatic network, and the points X and Y are used only to control the pressure in the third-party network using the block in question.

The block describes the flow of gas through a valve cross-section that regulates the pressure if the current differential across ports X and Y exceeds the setpoint value but does not exceed the maximum pressure.

The maximum pressure is the sum of the setpoint and the control range.

The pressure setpoint can be zero, the control range is strictly greater than zero. The smaller the monitoring range, the faster the valve position changes at pressure change (the control speed increases).

There are two modes of valve operation:

In the Constant mode, the pressure setpoint remains unchanged and is set via the Set pressure drop block property;
The ‘Controlled’ mode sets the setpoint by an external signal via the automation port.

Simulated valve can be:

Normally open (for example, reducing valve), maintaining the downstream pressure not higher than the set one;
Normally closed (for example, safety valve), maintaining the upstream pressure not higher than the set one.

Leakage area is the area of the hole when the valve is fully closed.

Note

Can be set to zero

Maximum area is the area of the hole when the valve is fully open.

Note

Should be set strictly less than valve port area

Provision is made for selecting a pressure recovery option.

Valve opening can be parameterized linearly or using tabular data.

If Opening parametrization is set to Linear, the hole area is a linear function of the piston valve travel distance (1) :

(1)#\[ A_{orifice}\:=\:\frac{(A_{max}-A_{leak})}{\Delta S}\:*\:\Delta S + A_{leak} \]

where:

\(A_{orifice}\) - open area;

\(ΔS\) — это расстояние перемещения золотника, введенное в порт S (2) :

(2)#\[Δ S = S -S_{max}+ ΔS_{max}\]

\(ΔS_{max}\) is the value of the parameter movement of the piston valve between the closed and open holes;

\(A_{leak}\) - value of parameter Leakage area;

\(A_{max}\) — value of parameter Maximum valve area.

Scaling from \(A_{Leak}\) to \(A_{max}\) is implemented linearly.

If set Opening parametrization to Tabulated, the clock uses piston valve travel vector and parameters Valve area vector, to determine the relationship between \(A_{orifice}\)and \(ΔS\) by interpolation. \(A_{leak}\) and \(A_{max}\) are the first and last parameter Valve area vector respectively.

Law of mass conservation (3) :

(3)#\[Min_1+Min_2+M_{out}=0\]

Law of conservation of energy (4) :

(4)#\[\phi_А+\phi_В=0\]

where:

\(\phi_A\) - energy flow at the input, [W];

\(\phi_В\) - energy flow at the output, [W].

1. Properties#

Property	Default value	Description	Units of measurement
Valve specification: Normally open; Normally close	Normally open	-	-
Set pressure drop: Constant; Controlled	Constant	-	-
Opening parametrization: Linear; Tabulated	Linear	-	-
Pressure recovery: Off; On	Off	-	-
Pressure drop set, available when selecting `Set pressure drop` - `Constant`	500	-	Pa
Pressure drop range, available when selecting `Opening parametrization` - `Linear`	10000	-	Pa
Laminar flow pressure ratio	0.999	-	-
Discharge coefficient, available when selecting `Pressure recovery` - `On`	0.64	-	-
Leakage area, available when selecting `Opening parametrization` - `Linear`	1e-10	-	m\(^2\)
Maximum valve area, available when selecting `Opening parametrization` - `Linear`	0.01	-	m\(^2\)
Port area	0.1	-	m\(^2\)
Smoothing factor	0.01	-	-
Presure drop vector, available when selecting `Opening parametrization` - `Tabulated`	2e5; 4e5; 6e5; 8e5; 1e6; 1.2e6	-	Pa
Valve area vector, available when selecting `Opening parametrization` - `Tabulated`	1e-5; 8e-6; 6e-6; 4e-6; 2e-6; 1e-10	-	m\(^2\)

2. Inputs and outputs#

Parameters	Input/output	Description	Units of measurement	Port type
Input	Input	-	-	Pneumatics
Control port X	Input	-	-	Pneumatics
Control port Y	Input	-	-	Pneumatics
Pressure drop, available when selecting `Set pressure drop` - `Controlled`	Input	-	Pa	Automation
Output	Output	-	-	Pneumatics

In order to see the connection capabilities of the block, you need to go to page Description of block ports