Compressed Air Reciprocating Pump Valve Stability
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Solution Overview
Problem
Compressed air driven reciprocating piston hydraulic pumps face issues with the main changeover valve going into a neutral position during low-speed piston motion, leading to instability and clattering noise due to pressure fluctuations and valve collisions.
Innovation Solution
The design incorporates an auxiliary changeover valve with a separate auxiliary valve body and tubular portion, utilizing a compression spring to bias the auxiliary valve body towards the air intake chamber, and a small diameter portion on the valve rod to release seals and control valve positions, ensuring reliable operation and silence by preventing all ports from opening simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the main changeover valve is biased toward air supply position by compressed air pressure, then the valve can respond to pressure changes, but when supply pressure drops the biasing force diminishes and the valve may go into neutral position causing all ports to open
Solution Approach 1:
A valve rod is introduced as an intermediary mechanical linkage between the piston and main changeover valve. The valve rod transmits the piston's reciprocating motion to reliably actuate the main changeover valve, ensuring stable valve positioning even when compressed air pressure fluctuates or drops, preventing the valve from drifting to neutral position
Solution Approach 2:
The piston performs preliminary reciprocating motion that mechanically drives the valve rod, which in turn actuates the main changeover valve before the compressed air pressure can cause instability. This preliminary mechanical action ensures the valve is properly positioned and prevents neutral position drift
2Loss of energy
If the piston moves at extremely low speed, then energy consumption is reduced, but the main changeover valve may go into neutral position due to insufficient pressure differential
Solution Approach 1:
The valve rod serves as a mechanical intermediary that translates even slow piston motion into reliable valve actuation. This mechanical coupling ensures that the main changeover valve responds to low-speed piston motion without requiring high compressed air pressure differentials, maintaining operational reliability at low speeds
Solution Approach 2:
The patent replaces reliance on compressed air pressure differentials with a direct mechanical linkage system (piston-valve rod-main changeover valve). This mechanical substitution ensures reliable valve actuation regardless of air pressure conditions, enabling stable operation at extremely low piston speeds
3Stability of the object's composition
If the main changeover valve goes into neutral position, then all ports open simultaneously causing instability, but increasing valve closing force may cause collisions and noise
Solution Approach 1:
The valve rod acts as a controlled intermediary that regulates the transmission of force from the piston to the main changeover valve. This controlled mechanical coupling prevents both neutral position drift and excessive closing forces, eliminating the need for high compression springs that would cause valve collisions and clattering noise
Solution Approach 2:
The mechanical linkage between piston, valve rod, and main changeover valve creates a feedback system where the piston's position directly controls valve positioning. This feedback mechanism maintains stable port configuration without requiring excessive closing forces, preventing valve collisions and noise generation
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 configuration stabilizes the operation of the main changeover valve, preventing it from entering a neutral state and reducing noise by ensuring precise valve control, even with fluctuating compressed air pressures, and enhancing durability by eliminating metallic collisions.
Implementation Method 1
a compression spring, and a small diameter portion on the valve rod to release seals and control valve positions
Implementation Method 2
along with an end portion of the tubular portion of the auxiliary valve body being faced into the air discharge outlet, compressed air flowing into the air intake chamber little by little operates on the auxiliary piston portion
Data Source
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AI summary
[Problem] In a compressed air driven hydraulic pump (P), continuous reciprocating operation of a piston (14) is implemented by a main changeover valve (42A) that changes over a compressed air supply system, and by an auxiliary changeover valve (42B) that changes over the main changeover valve (42A) between an air supply position and an air discharge position; but in some cases the main changeover valve (42A) is in a neutral position (an all ports open state) when the piston (14) is operating extremely slowly. [Solution] First and second annular valve faces (51, 52) that approach closely or contact against first and second annular valve seats (53, 54) on valve cases (31, 32) are formed on both the upper and the lower ends of an annular valve body portion (43a) of a main valve body (43), an air intake chamber (55) is defined by a piston reception hole (45) and a piston portion (46), and the auxiliary changeover valve (42B) changes over the main changeover valve (42A) between its air supply position and its air discharge position by supplying compressed air to the air intake chamber (55) or discharging air therefrom. A center side portion of the main valve body (43) is made as a separate auxiliary valve body (43A). The sealing of a second valve member (57) is released by the auxiliary valve body (43A) being rapidly shifted with low pressure compressed air, and thereby the main valve body (43) is reliably changed over.