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Bearings and exhaust valves are components of vital importance to the engine of a motor‐car. They operate under conditions which favour corrosive attack, and the problem of mitigating this attack is made more difficult, in the case of the bearings, by the tendency towards increasing engine power and, in the case of the exhaust valves, by the use of petrols containing tetra‐ethyl lead. Previous articles by Mr. Michalewicz in this series have appeared in CORROSION TECHNOLOGY in the issues of August 1954 (‘Corrosive Wear of Piston Rings and Cylinders’), November 1954 (‘The Cooling System’) and March 1955 (‘The Bodywork’).

Looks at a system for diagnosing valve performance which works by measuring or inferring dynamic parameters such as valve travel, friction, seat load, seat contact and supply pressure by using sensors attached to the valve instrumentation. The system, which can be used in a factory or to taken to a valve on site, interprets the results and stores the test data. Gives application examples in the fertiliser and paper industries and continues that the next step will to embed diagnostics within the valve instrumentation itself. Concludes that the concept of “total valve management” in reducing costs helping plants operate more effectively will become increasingly important to manufacturers in coming years.

The hardware and software development of a remotely controlled hydraulic valve assembly is described. The valve becomes a dedicated server in a distributed control environment. The communication system is an Ethernet network supporting the UDP/IP communications protocol. A client/server application model is developed that allows a client to specify a desired control position for a valve spool. The solution is being proposed as an alternative to a formal fieldbus solution, where precision real‐time operation is not required. The performance of the valve is measured under different configurations considering both open loop and closed loop models. The justification for selecting the UDP/IP protocol is stated. The resulting hydraulic valve control system is efficient, accurate and flexible.

Aiming at the cavitations and noise problem of hydraulic cone valve and based on the radial force analysis of the valve core, the radial deviation of the spool is considered to obtain the changing rules of cavitations and noise.

The solid model of the internal flow field of cone valve is established. The mesh models are divided using ICEM-CFD software. The numerical simulation of the liquid-gas two-phase flow is performed on the cavitation and noise of the flow field inside the cone valve based on FLUENT software. The visible experimental platform for cavitation and noise of hydraulic cone valve is built. According to the contrast of the experimental results, the correctness of the simulation results is verified.

The results show that the radial deviation causes the position of the cavitation accumulates in the valve cavity on the side of the upper cone. In addition, the strength of the cavitation changes slowly with the half cone angle of 45°, and the noise level is the smallest. Furthermore, appropriately increasing the opening degree within a reasonable range can effectively suppress cavitation and reduce the noise level.

The cavitation can be suppressed and the noise level can be reduced by means of changing the three factors, which lays the foundation for the design and theoretical research of the cone valve.

The purpose of this paper is to study the variation of cavitation scale with pressure and flow in poppet throttle valve, to obtain the cavitation scale under pressure and flow conditions and to provide experimental support for the research of suppressing throttle valve cavitation and cavitation theory.

A hydraulic cavitation platform was set up, a valve was manufactured with highly transparent PMMA material and a high-speed camera was used to observe the change in cavitation scale.

Through experiments, it is found that the pressure difference between inlet and outlet of throttle valve affects the cavitation scale, and the more the pressure difference is, the easier the cavitation will be formed. Under the condition of small pressure difference, the cavitation is not obvious and reducing the pressure difference can effectively suppress the cavitation; the flow rate also affects the cavitation scale, the smaller the flow rate, the more difficult the cavitation will be formed and the lower the flow rate, the more the cavitation will be suppressed.

Because of the magnification factor of the high-speed camera lens, the morphology of smaller bubbles cannot be observed in this study, and the experimental conditions need to be improved in the follow-up study.

This study can provide experimental support for the study of throttle valve cavitation suppression methods and cavitation theory.

THE speed at which a valve is coming to rest on its scat at the moment of closing is one of the factors deciding the amount of gases passed through the valve. The inertia forces, however, act for a very short time on the valve at this moment, and this is the reason why normal considerations in the strength of valves are not accurate; it would be better, when designing the valve, to use approximate calculations giving the possibility of orientation among the various factors coming into consideration, than to leave all this to experimental practice.

This paper aims to resolve the cavitation problem encountered in cone throttle valves concerning fluid flow performance and pitting from cavitation luminescence, the author studied the flow field within a cone throttle valve set with various valve openings, inlet pressures and outlet back pressures.

The flow and cavitation distribution in the valve under different pressure conditions were obtained in simulations. To confirm these results experimentally, a hydraulic cavitation platform was constructed. The valve was made of polymethyl methacrylate material with high transparency to observe the cavitation directly, as well as cavitation luminescence. The flow characteristics of this valve were measured under various working conditions.

With increasing cavitation strength, a reduction in cavitation on the throttle capacity was more evident. Increasing the back pressure and reducing the working pressure of the valve appropriately improves the flow capacity of the valve, which subsequently improves the performance of the valve. The cavitation luminescence is also linearly related to cavitation intensity. That is, the stronger the flow capacity of the valve, the less likely the luminescence is produced. Moreover, a stronger luminescence intensity worsens the flow performance of the valve.

Owing to the limitation of experimental means and lack of research on bubble shape, the subsequent research will complement this aspect.

With a view to providing theoretical and experimental support, cavitation luminescence is also studied to gain a deeper understanding of the cavitation mechanism in hydraulic valves.

The innovation of this paper is to study the cavitation luminescence in the hydraulic system.

PROMINENT among hydraulic servos today are those being developed in the aeronautical field, both for conventional aircraft and for guided missiles. In general these applications demand the following characteristics of the servos:

THE COMPLEXITY of modern pressurisation and air conditioning systems for jet aircraft have led increasingly to the practice of selecting a single contractor to design and integrate all of the components into a compatible system tailored to the mission requirements of the aircraft.

Globe valves have good throttling ability, which permits its use in regulating flows. This paper aims to understand in detail the globe valve with different cage configurations and its impact on the flow characteristics that was carried out.

The computational study was carried out using FLUENT, a finite volume-based numerical code. Grid sensitivity tests were done and the results were validated experimentally. The effect of cage configuration on flow characteristics and valve coefficient was studied and optimised.

Valve coefficient was found to be dependent on cage configuration and reaches its maximum for the valve with triangular shaped aperture. Methodology to improve flow performance of a globe valve with highest valve coefficient is established.

Studies related with caged-type globe valves having different configurations are useful for improving their flow performance. In the present investigation, globe valves with different cage configurations and throttle positions are modeled to find out the valve coefficient, pressure and velocity contours inside and outside the cage and is validated with experimental results.