Balance Valve Research Articles

水圧用リリーフ弁の動特性解析

This paper deals with dynamic characteristics of a balanced piston type relief valve for water hydraulic use. Mathematical model for the valve has been derived as ordinary differential equations of 8th order. Effects of various structural parameters on the stability of the system have been investigated by eigenvalue analysis. As a result, it has been shown that the system stability can be improved by making the middle chamber volume of the valve and the pilot valve mass as small as possible. Furthermore, it has been found that the existence of a drain pipeline markedly affects the instability of the valve mode.

NUMERICAL SIMULATION OF WATER HYDRAULIC RELIEF VALVE

This paper deals with numerical simulation of a balanced piston type water hydraulic relief valve. A mathematical model for the valve is derived as ordinary differential equations of 1 lth order and the validity of the model is examined by the comparison with experimental results. The simulation results qualitatively agree well with the experimental ones. Then, the model is linearized around a steady operating point. The stability of the system is studied by a root locus method and the effects of various structural parameters on the stability of the system are investigated. As a result, it is clarified that the middle chamber volume influences the stability of the system markedly.

バランスドピストン型リリーフ弁動特性の数値解析 第２報 リリーフ弁の安定性

In this paper, the authors have studied the stability of a balanced piston type relief valve on the basis of a mathematical model derived and confirmed to be valid qualitatively in the previous paper. It has been demonstrated that the stability of a relief valve can be easily analyzed by a method dividing the overall operating region into two parts by the cracking condition of the main valve. The analysis shows that the stability of a relief valve is subject to the stability of the pilot part.

96/01988 Balanced bellows valves — A thing of the past?

96/01988 Balanced bellows valves — A thing of the past?

STUDY OF HYDRAULIC SEMI-ACTIVE SUSPENSION (DERIVATION OF MATHEMATICAL MODEL AND NUMERICAL SIMULATION)

In this paper, a mathematical model for a semi-active damper, in which a pressure regulating mechanism similar to a balanced piston type relief valve is built-in, is derived. The Numerical simulation results of the damping force characteristics are in good agreement with the experimental ones. It implies that the mathematical model is available. Furthermore, effects of various parameters on the stability of the system are investigated on the basis of this model.

SEMI-EMPIRICAL MODEL FOR A COUNTER BALANCE VALVE

The semi-empirical method is employed in modelling a commercially used counter balance valve for hydraulic crane circuit simulation applications. By means of the method the analytical model of the valve is brought into a form in which the number of the parameters whose values can be determined from the measured characteristic curves is small. The particular problems apparent when modelling the counter balance valves such as description of high seal friction and complicated flow force characteristic are solved by using pure empirical functions.

Research on improving dynamic characteristics of counter balance valve

Counter balance valve is an important control element used in hydraulic balance circuits. This paper introduces the working principle, mathematic model and computer simulation results of a hydraulic balance circuit. From the theoretic analysis and simulation, it can be seen that under the condition of big flow or after 2/3 spool stroke, the system would be unstable. The authors suggest that a construction of flow section area with changeable gain and a spring with gradually reducing rigidity should be used to resolve the contradiction between fast response and stability.

Balanced puff valve for imploding gas-puff experiments

The design of a fast-acting high-pressure puff valve for use in imploding gas-puff experiments is presented. By using a pressure-balanced valve design, the valve can operate at pressures up to 500 psia. Fast opening (≊200 μs) is achieved by using a fast-moving sliding hammer to open the valve. Balanced valves as well as fast-opening valves using sliding hammers are both well-known technologies; however, this design is the first one to incorporate both features in a single design resulting in a fast-acting high-pressure puff valve.

Dynamic force measurement with a hydraulic force balance valve

A hydraulic force balance transducer for measuring force is presented. The useful output is in the form of a pressure signal which could be used directly in hydraulic amplification stages of low-frequency high-power-output servo systems. Typically, the device could be designed to have a capacity of about 20 N and a frequency range of operation of 0-30 Hz.

カウンタバランス弁を含む油圧回路の安定性

Valve-controled hydraulic drives suffer often from the disadvantage that the operation becomes unstable and self-excited vibration arises. These vibrations are, strictly speaking, self-excited vibrations of hydraulic circuit that arise by interaction of the all elements in hydraulic system, such as control valve, fluid line, actuator, etc.This paper discusses the stability problem of hydraulic circuit by giving an example of self-excited vibration phenomena of a vertical hydraulic cylinder circuit including a counter balance valve. The relationship between the oscillation mechanism and the pilot systems of counter balance valve (namely, internal and external pilot system), the effects of dimensions of control valve, fluid line and actuator on stability margin and chatter frequency, etc. are become evident by theoretical and experimental analysis.

Pollution control in the operating room: a simple device for the removal of expired anaesthesia vapours.

A modification of the Bird Mark II gas balance valve is described for the purpose of controlling the pollution of the operating room by the fumes of volatile anaesthetic agents. This modification can be carried out by any good machine shop. The valve is adaptable to all anaesthetic machines and is easily dismantled for cleaning and sterilizing. In regular use it has completely eliminated the odour of halothane and methoxyflurane in the operating room and for that reason it has been nicknamed the “stink valve” by the staff. Its use has resulted in a subjective improvement in the symptoms experienced by the author.

A New Circuit for balancing the Characteristics of Pairs of Valves

IN circuits containing balanced valves, as used in such applications as push-pull output stages or in d.c. amplifiers, it is customary to balance the valves by means of external circuit adjustments so that errors caused by differences in their characteristics are reduced. There are various methods of doing this1; but none of these gives compensation for all characteristics simultaneously, as it is possible to make adjustments to only one of the three properties, namely, zero balance (equality of static plate currents), stage gain and effect of changes of cathode-supply voltage.

The pneumatic balance valve and its applications: a preliminary report.

The pneumatic balance valve and its applications: a preliminary report.

U.S. Patent Specifications

A temperature control for aircraft instruments comprising in combination an aircraft engine having a hot oil sump and a relatively cool oil sump, conduits from said sumps, a mixing valve having intakes connected individually to said conduits, a discharge conduit from said mixing valve, and a thermostatically controlled balanced valve for varying the openings respectively from said hot and cold conduits to said discharge conduit, said thermostat control being housed within said discharge conduit and said discharge conduit extending to an instrument panel board.

A balance-detector for alternating-current bridges

A balanced valve arrangement with a portable d.-c. galvanometer of pointer type is described for use as balance-detector in a.-c. bridge work. Over an extensive range of frequencies its sensitivity is comparable to that of a vibration galvanometer or telephone. The direction of deflection shows which way the bridge must be adjusted to secure a balance as in the case of a d.-c. bridge or electrodynamometer, but the false-zero effect found with the latter is absent. The arrangement could be adapted for use at radio frequencies.

A Valve Amplifier for the Detailed Study of Radium Isodose Curves

A balanced valve amplifier is described for use with a graphite ionisation chamber of 3 c.mm. volume. Measurements were made of the intensity distribution at distances between 3 mm. and 15 mm. from the centre of radium preparations. The results indicate that the simple Sievert formulae for intensity distribution are, to a close approximation, applicable.

Balanced Valves

Balanced Valves