Check Valve Attachment Detection in Plunger Pump Inlets
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Solution Overview
Problem
Check valves in liquid sending devices, such as those used in liquid chromatographs, face issues with rapid wear of the pin due to frequent operation and contamination, leading to reduced liquid-tightness and potential loss of function when the valve element is attached to the valve seat, as existing solutions require active operation for all valve openings without reliable attachment detection.
Innovation Solution
A liquid sending device equipped with a pressure sensor to detect the pressure in the pump chamber and compare it to a preset threshold, allowing for the detection of valve element attachment to the valve seat, and a valve element drive controller to actively operate the valve element only when attachment is detected, reducing wear by minimizing unnecessary active operations and using materials and coatings like diamond-like carbon for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve element is actively operated by pressing with a pin for all opening operations, then the valve element can reliably detach from the valve seat, but the pin wears quickly due to frequent sliding
Solution Approach 1:
The patent changes the operational parameter of the valve element from active pressing for all openings to passive operation triggered by pressure differential. The pressure in the pump chamber serves as the controlling parameter that automatically opens the valve when liquid is present, eliminating the need for frequent active pin operation and reducing wear.
Solution Approach 2:
The valve element performs self-service by automatically opening through pressure differential when liquid enters the pump chamber. The system uses the liquid pressure itself to open the valve, rather than requiring external active actuation by the pin, thereby reducing mechanical wear on the pin while maintaining reliable valve operation.
2Reliability
If the pin slides frequently inside the valve seat for active valve operation, then the valve element detaches reliably, but abrasion powder is generated and caught between the valve seat and valve element
Solution Approach 1:
The patent transitions from active mechanical pressing to passive pressure-driven operation. The pressure differential parameter naturally controls valve opening, eliminating frequent pin sliding and the generation of abrasion powder that would compromise liquid-tightness.
Solution Approach 2:
The patent converts the harmful effect of frequent pin sliding and abrasion powder generation into a beneficial passive pressure-driven mechanism. By using the liquid pressure itself to open the valve, the system eliminates the source of abrasion while maintaining reliable valve function.
3Ease of operation
If active operation is used for all valve openings, then attachment detection is not required, but the number of active operations increases and wear accelerates
Solution Approach 1:
The patent changes the control parameter from active electrical/magnetic actuation to passive pressure differential. The pressure in the pump chamber becomes the controlling parameter that automatically opens the valve, simplifying operation while dramatically reducing pin wear and extending durability.
Solution Approach 2:
The valve element serves itself by using the pressure differential to open automatically when liquid enters the pump chamber. This self-service mechanism eliminates the need for continuous active control while maintaining ease of operation and extending pin life.
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 reliable detection of valve element attachment, reducing wear and maintaining liquid-tightness by minimizing unnecessary active operations of the valve element, thus extending the lifespan of the check valve and ensuring consistent operation.
Implementation Method 1
a pressure sensor that detects the pressure in the pump chamber of the plunger pump
Implementation Method 2
in a case where the plunger pump performs an intake operation, the pressure in the pump chamber becomes negative (lower than the atmospheric pressure), and the valve element is attracted toward the pump chamber by the negative pressure
Data Source
AI summary
A liquid sending device includes a plunger pump, which performs an intake operation of liquid to and a discharge operation of liquid from a pump chamber and in which pressure in the pump chamber in a case where the intake operation is performed is lower compared to a case where the discharge operation is performed, a check valve that is provided at an inlet port, has a spherical valve element and a valve seat, and passively operates according to the pressure in the pump chamber in such a direction that the valve element is seated on or detached, a pressure sensor that detects the pressure, and an attachment detector that compares the pressure with a preset threshold value and detect attachment of the valve element to the valve seat in a case where the pressure in the pump chamber is equal to or lower than the threshold value.