Pump Relief Valve with Independent Pressure and Thermal Bypass
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Solution Overview
Problem
Positive displacement pumps are vulnerable to damage from both overpressurization and overheating, particularly when discharge flow is blocked, leading to thermal expansion and potential vaporization of fluids, which existing pressure relief mechanisms may not adequately address independently.
Innovation Solution
A pressure and thermostatic relief valve system that includes a pressure relief actuator and a thermostatic relief valve with a wax element, allowing independent relief of pressure and temperature differences, featuring a poppet mechanism to control fluid flow between the discharge and suction sides, and an adjustment screw to vary the bias on the pressure relief spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If discharge flow is blocked, then pressure buildup occurs, but fluid overheating and thermal expansion damage occur simultaneously
Solution Approach 1:
The relief valve assembly acts as an intermediary safety device between the pump discharge and the blocked downstream system. It monitors both pressure and temperature conditions and provides a controlled relief path when either parameter exceeds safe limits, preventing the harmful combination of pressure buildup and thermal expansion that would otherwise damage the pump.
Solution Approach 2:
The device responds to changes in physical parameters (pressure and temperature) by activating different relief mechanisms. When pressure exceeds the spring-set threshold, the pressure diaphragm activates. When temperature causes wax expansion, the thermostatic section activates. This parameter-based activation ensures appropriate relief action for the specific hazard condition present.
2Device complexity
If a single relief valve is used, then device simplicity is maintained, but independent relief of pressure and temperature is not achieved
Solution Approach 1:
The relief valve is divided into two independent functional components: a pressure relief section with a pressure-sensitive diaphragm and a thermostatic relief section with a temperature-sensitive wax element. Each section independently monitors and responds to its specific parameter (pressure or temperature), allowing simultaneous protection against both overpressurization and overheating without interference between the functions.
Solution Approach 2:
The thermostatic relief section is nested within the pressure relief valve housing. The wax element and second piston assembly are contained within the same valve body as the pressure diaphragm and first piston, creating a compact integrated structure. This nested arrangement allows independent temperature relief functionality to be incorporated within the existing pressure relief framework without significantly increasing overall device complexity.
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
Enables separate and independent relief of pump overpressurization and overheating, preventing substantial damage from thermal expansion by allowing fluid flow even if pressure is insufficient to open the pressure relief valve, thus protecting the pump from overheating-related damage.
Implementation Method 1
expansion of the wax thermostatic element under elevated temperature conditions moves the thermostatic actuator piston from a first position to a second position
Data Source
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AI summary
A pressure and thermostatic relief valve for a pump housing is disclosed. The relief valve includes both a pressure relief valve mechanism and a thermostatic or temperature relief valve mechanism. A pump housing incorporating the pressure and thermostatic relief valve is also disclosed.