The inherent characteristics of three control valves P, Q and R are shown in the figure.
The CORRECT option(s) is/are
The inherent characteristics of three control valves P, Q and R are shown in the figure.
The CORRECT option(s) is/are
Show Hint
- P is a quick opening valve
- Q is a quick opening valve
- P is an equal percentage valve
- R is an equal percentage valve
The Correct Option is A, D
Solution and Explanation
Quick opening valve: Large flow increase at small lift — curve rises rapidly then levels off.
Linear valve: Flow increases proportionally with lift — straight line.
Equal percentage valve: Slow initial rise, then sharp increase — exponential-like curve.
Analysis of curves:
• Curve P rises very quickly at the beginning and then flattens → typical of a quick opening valve.
• Curve Q is nearly straight → typical of a linear valve.
• Curve R rises slowly at the start and accelerates towards the end → this is an equal percentage valve.
Thus, the correct statements are: (A) P is a quick opening valve, (D) R is an equal percentage valve.
Top Questions on Control valves
- A PD controller with transfer function \( G_c \) is used to stabilize an open-loop unstable process with transfer function \( G_p \), where: \[ G_C = K_C \frac{\tau_D s + 1}{\tau_D s}, \quad G_P = \frac{1}{(s - 1)(10s + 1)}, \] and time is in minutes. From the necessary conditions for closed-loop stability, the maximum feasible value of \( \tau_D \), in minutes, rounded off to 1 decimal place, is \_\_\_\_\_\_.
- A \(\frac{4}{2}\) direction control valve used in pneumatic system is:
- Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion (A): The hydraulic actuating system operates more slowly in comparision to pneumatic system.
Reasons (R): The viscosity of the oil used in the hydraulic actuating system is higher.
In the light of the above statements, choose the most appropriate answer from the options given below:
Questions Asked in GATE CH exam
Consider a process with transfer function: \[ G_p = \frac{2e^{-s}}{(5s + 1)^2} \] A first-order plus dead time (FOPDT) model is to be fitted to the unit step process reaction curve (PRC) by applying the maximum slope method. Let \( \tau_m \) and \( \theta_m \) denote the time constant and dead time, respectively, of the fitted FOPDT model. The value of \( \frac{\tau_m}{\theta_m} \) is __________ (rounded off to 2 decimal places).
Given: For \( G = \frac{1}{(\tau s + 1)^2} \), the unit step output response is: \[ y(t) = 1 - \left(1 + \frac{t}{\tau}\right)e^{-t/\tau} \] The first and second derivatives of \( y(t) \) are: \[ \frac{dy(t)}{dt} = \frac{t}{\tau^2} e^{-t/\tau} \] \[ \frac{d^2y(t)}{dt^2} = \frac{1}{\tau^2} \left(1 - \frac{t}{\tau}\right) e^{-t/\tau} \]- GATE CH - 2025
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Choose the transfer function that best fits the output response to a unit step input change shown in the figure:
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An electrical wire of 2 mm diameter and 5 m length is insulated with a plastic layer of thickness 2 mm and thermal conductivity \( k = 0.1 \) W/(m·K). It is exposed to ambient air at 30°C. For a current of 5 A, the potential drop across the wire is 2 V. The air-side heat transfer coefficient is 20 W/(m²·K). Neglecting the thermal resistance of the wire, the steady-state temperature at the wire-insulation interface __________°C (rounded off to 1 decimal place).
GIVEN:
Kinematic viscosity: \( \nu = 1.0 \times 10^{-6} \, {m}^2/{s} \)
Prandtl number: \( {Pr} = 7.01 \)
Velocity boundary layer thickness: \[ \delta_H = \frac{4.91 x}{\sqrt{x \nu}} \]- GATE CH - 2025
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The first-order irreversible liquid phase reaction \(A \to B\) occurs inside a constant volume \(V\) isothermal CSTR with the initial steady-state conditions shown in the figure. The gain, in kmol/m³·h, of the transfer function relating the reactor effluent \(A\) concentration \(c_A\) to the inlet flow rate \(F\) is:
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