Pilot Actuator Pressure Decoupling for Dry Sprinkler Valves
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Solution Overview
Problem
Conventional fire suppression sprinkler systems face challenges in maintaining consistent gas pressure, leading to increased leakage rates and operational costs due to higher operational pressures required to prevent false trips, which can be prohibitive in certain applications like residential use.
Innovation Solution
A pilot actuator with a low trip setpoint variance ratio, allowing the trip pressure to remain relatively constant across a range of inlet pressures, is designed to control the control valve by maintaining gas pressure in the sprinkler piping network, reducing the need for frequent compressor operation and minimizing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher operational pressure is used in the sprinkler piping network, then the control valve remains more reliably closed (preventing false trips), but the gas leakage rate increases and compressor operation frequency increases
Solution Approach 1:
The patent changes the pressure parameter relationship by introducing a pilot actuator that decouples the control valve's closing pressure requirement from the network operating pressure. The pilot actuator maintains a constant prime chamber pressure (e.g., 50 psi) regardless of network pressure variations, allowing reliable valve closure at lower network pressures (10-20 psi) without requiring proportionally higher pressures to prevent false trips.
Solution Approach 2:
The pilot actuator serves as an intermediary device between the network pressure source and the control valve. It uses a pilot line to sense network pressure and automatically adjusts the prime chamber pressure to maintain valve closure, eliminating the need for direct high-pressure maintenance in the entire system and reducing overall gas leakage.
2Reliability
If higher operational pressure is maintained in the sprinkler piping network, then false trips are prevented, but operational costs increase due to more frequent compressor operation
Solution Approach 1:
The pilot actuator changes the pressure parameter relationship by maintaining a constant prime chamber pressure independent of network pressure fluctuations. This allows the system to operate reliably at lower network pressures, reducing the need for frequent compressor cycling to maintain high pressures, thereby lowering energy consumption and operational costs.
Solution Approach 2:
The pilot actuator implements a feedback mechanism where the pilot line continuously monitors network pressure and automatically adjusts the control valve's prime chamber pressure in response. When network pressure drops, the pilot actuator maintains sufficient prime chamber pressure to prevent false trips without requiring proportional increases in network pressure, reducing unnecessary compressor operation.
3Adaptability or versatility
If the trip pressure set point varies significantly with inlet pressure, then the pilot actuator responds to pressure changes, but system complexity increases and constant pressure maintenance becomes difficult
Solution Approach 1:
The patent applies parameter changes by designing the pilot actuator with a fixed orifice and spring mechanism that creates a predictable, stable relationship between pilot line pressure and prime chamber pressure. This standardized parameter relationship simplifies the device design and makes the system easier to install and maintain, while still providing appropriate response to pressure changes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution maintains consistent operational gas pressure across varying inlet pressures, reducing leakage and operational costs while allowing the use of lower-pressure piping materials, enhancing the system's reliability and cost-effectiveness.
Implementation Method 1
the sprinkler piping is filled with a compressed gas... The compressed gas can be air or another type of gas such as, for example, nitrogen
Implementation Method 2
an actuator assembly disposed in the interior chamber so as to divide the interior chamber into a first chamber and a second chamber
Data Source
AI summary
A pilot actuator for controlling the operation of a control valve. The control valve can be part of a dry-type fire suppression sprinkler system in which the sprinkler piping network is filled with pressurized gas such as, for example, air, nitrogen, or another gas. The pilot actuator is a differential valve that actuates the control valve when the gas pressure in the sprinkler piping network is at or below a value for tripping or actuating the pilot valve to the open position. The pilot actuator has a ratio of a change in a trip pressure set point to a change in an inlet pressure that is in a range of 0.007 to 0.045.