Showing papers on "Damper published in 1984"

Variable volume multizone system

Abstract: A zoned variable volume system is provided with a pair of non-connected dampers in each zone. The first damper controls flow through a cooling coil. The second damper controls flow through a heating coil and provides heated or neutral air depending upon whether or not the heating coil is actuated. The fan speed is adjusted to cause at least one damper to be fully open so that the system operates at a minimum static pressure.

On-off thermostat based modulating air flow controller

Abstract: A system for providing modulated air flow control in response to an on-off thermostat having an on-off thermostat, a self-returning, slow moving motor connected to the thermostat for moving in a first direction when the thermostat is on and moving in a second direction when the thermostat is off, a damper motor adapted to drive a damper, and a controller driven by the self-returning, slow moving motor and connected to the damper motor for modulating air flow in response to the on-off thermostat.

Damping Increase in Building with Tuned Mass Damper

Abstract: The Sydney Tower, the tallest building in Australia, is 820ft (250m) high and with the base of the structure anchored on the roof of a 15 storey building, it stands 1000ft (305m) above street level The tower is one of the first buildings with the installation of a large scale tuned mass damper (TMD) The doughnut-shaped water tank near the top of the turret, which normally serves as the tower’s water and fire protection supply, was incorporated into the design of the TMD to reduce wind-induced motions Energy associated with relative movements between the tower and the water tank is dissipated by 8 shock-absorbers installed tangentially to the tank and anchored to the floor of the turret A secondary TMD of similar design was later installed on the intermediate anchorage ring to further increase the damping level, particularly in the second mode Full scale measurements were taken to determine the natural frequencies of vibration and damping Dampings of the tower were determined for different damper configurations The natural frequencies of vibration were found to be 010 Hz and 050 Hz for the first mode and second mode respectively Significant increases in damping levels, particularly in second mode, are produced by the water tank tuned mass damper and the secondary damper

Kitchen ventilating system

Abstract: A cooking or ventilating system has an extraction unit connected through an exhaust duct with the outside atmosphere, and a damper which is shiftable between positions operatively opening or closing the exhaust duct A mechanism for opening and closing the damper under power includes an electric motor and a ball screw linear actuator driven by the motor Air flow through the system is controlled to prevent exhausted grease from being carried up the exhaust duct The damper is mounted for closing in the direction of air flow through the system and, when opened, for shielding the drive mechanism from smoke and grease, etc, in the air flow Control circuits provide automatically timed normal operation of the motor as well as control operation of detergent and spray wash apparatus of the ventilating system The control circuits also include a thermosatic sensor arrangement for sensing temperatures within the extraction unit In the event of a fire, the damper is closed by automatically initiated operation of the motor and water spray through the spray wash apparatus is initiated

Effects of Static Friction on the Forced Response of Frictionally Damped Turbine Blades

Abstract: The effect of static friction on the design of flexible blade-to-ground vibration dampers used in gas turbine engines is investigated. It is found that for γ (ratio of dynamic and static friction coefficients) less than 1, the steady-state response is essentially harmonic when the damper slip load, S, is small. However, as S increases beyond a certain value, the steady-state response ceases to be simply harmonic and, while still periodic, is a more complex waveform. The transition slip load is found to be lower for smaller γ. The maximum possible reduction in vibratory stresses increases as γ decreases. These analytical results are compared with those from the conventional numerical time integration method. In addition, an efficient time integration algorithm is described which can be used to predict the peak displacements of the transition solution without tracing the whole waveform, a useful procedure when no harmonic steady-state solution exists. The conditions under which blade response can be adequately modeled by simulating only dynamic friction are established.

Vibration isolation assembly.

Abstract: An assembly for adaptively controlling vibration, shock, acceleration and position of an item mounted to the assembly independent of varying operating characteristics of the item or a support base for the assembly is provided. The assembly comprises an item to be controlled, a support platform for supporting the item, a viscous spring damper mechanically intercoupled between the item and the platform, a first accelerometer for sensing vibration, shock, acceleration and position of the item, a second accelerometer for sensing vibration, shock, acceleration and position of the support platform, a gas supply source for selectively supplying gas to the viscous spring damper, a fluid supply source for selectively supplying fluid to the viscous spring damper, and a logic control circuit for adjusting inputs from the gas supply source and the fluid supply source to selectively adjust the operation of the viscous spring damper and the dynamic mechanical coupling of the item to the platform. The invention is particularly applicable as a mechanical coupler system to be used for the support of vibrating machinery on submarines.

Proportional fluid exchanger and recirculator

Abstract: A proportional fluid exchanger and recirculator having a damper element pivoted at its approximate balance point for thermostatically-responsive proportioning of fluid within a mixing chamber. Said damper element supports actuator elements, thus permitting ready installation at jobsite.

Stand structure for supporting electric high voltage equipment

Abstract: A platform for carrying electric high-voltage equipment, such as series-capacitors etc., is supported by insulator columns which are articulated at the upper and lower ends. Bracing takes place with the aid of diagonally-braced insulators which are connected together by means of ropes via a prestressed spring damper. The means provides a high damping and a low natural frequency in case of earthquake stresses. Through the prestressing of the spring damper, the platform will remain stationary at low loads such as wind loads.

Oil type damper

Abstract: An oil type damper comprises a housing, a rotator formed of a hollow shaft and a braking disk, a flexible membrane, a toothed wheel secured to the leading end of the aforementioned hollow shaft, and oil introduced via the hollow shaft into the housing. Since the oil is introduced through the hollow shaft into the housing after the rotator and the flexible membrane have been set in place inside the housing, the work of filling the damper with oil is easy. The flexible membrane absorbs thermal expansion of the oil and precludes otherwise possible oil leakage.

Computer controlled air conditioning systems

Abstract: @ Building construction techniques are afforded permitting simplified air conditioning with very low energy consumption. Thus, by use of concrete outer wall construction in a house, or the like, placed substantially underground, the concrete temperature assumes the underground temperature, which remains in the interval 21-27°C year around, a preferred temperature for human comfort. The concrete walls are an integral radiating part of a heat pump circulating building air over substantially the entire concrete inner surface area to maintain the building air at the underground temperature. This requires modified building structure to provide air flow passages between inner and outer walls. It also permits heat control by a new method of merely controlling circulating air. This adapts to simplified control by a programmable electronic computer of the circulating air flow in response to sensed input parameters to achieve various goals defined by algorithms processed in the computer, based upon historical performance and/or current conditions and goals set by manual control of thermostats, or long term defined controls, in particular for the protection of the concrete walls against deterioration due to drastic changes in humidity such as may be incurred in the wintertime by scavenging moisture from the walls or in drought periods by lack of moisture in the ground.

Rotary damper having a clutch spring and viscous fluid

Abstract: A rotary damper with a directional property is disclosed which is capable of being simplified in structure, manufactured with a low cost, and stably and precisely operated. The rotary damper is constructed in such a manner that a clutch spring is interposed between a revolving shaft and a rotor to selectively carry out the integral rotation of the rotor with the shaft or the stop of the rotor independent from the shaft.

Oil filled rotary damper having a symmetrically shaped flexible membrane

Abstract: An oil type damper for braking and absorbing the opening-closing motion of a lid in a cassette tape recorder, video recorder or the like is improved by incorporating therein a flexible membrane formed in a structure symmetrical with respect to the obverse and reverse sides thereof, interposed between a housing and a braking disk, and adapted to absorb thermal expansion of oil and produce a sealing effect and, at the same time, causing the shaft projected from the braking disk for supporting the flexible membrane in place to contain a flared base radially diverged downwardly. Since the flexible membrane has a structure symmetrical with respect to the obverse and reverse sides thereof, the possibility of incorrect assembly of the oil type damper is minimized and the operational efficiency of damper production is increased without sacrificing sealing effect.

On a Magnetic Damper Consisting of a Circular Magnetic Flux and a Conductor of Arbitrary Shape. Part I: Derivation of the Damping Coefficients

Abstract: Theoretical results for finding the damping coefficients of a magnetic damper consisting of a circular magnetic flux and an arbitrarily shaped conductor have been obtained. In the analysis the exact solution in polar coordinates for the governing equation of the electromagnetic fields is utilized. The boundary condition for arbitrarily shaped boundaries of the conductor is satisfied directly by means of the Fourier expansion collocation method. To discuss the accuracy of the present approximate results, the analysis also has been performed on damper consisting of a circular flux and a circular conductor. The comparison between the present results and the exact ones for the typical damper shows very good agreement.

Air conditioning device

Abstract: PURPOSE:To prevent the temperature of blown-off air from lowering due to the lowering of the outdoor air temperature and consequently perform comfortable air conditioning by a method wherein the rate of circulating air flow is controlled in response to the height of the temperature of the air blown-off in a passenger compartment during the heating running of a heat pump air conditioning device. CONSTITUTION:The high temperature, high pressure and gaseous refrigerant discharged from a compressor 11 passes through a passage of a four-way change-over valve 12 as indicated with the dash line, enters an indoor heat exchanger 16 acting as a condenser, heat-exchanges with the circulating air supplied by means of an indoor fan 17 from a passenger compartment 4 in order to perform heating action, turns into liquid refrigerant and enters an expansion mechanism 15. When the lowering of heating capacity due to the lowering of the outdoor air temperature causes the lowering of the temperature of the air blown-off, said temperature drop is detected by a temperature sensor 20. When the detected temperature is lower than the set value, the output signal of the sensor 20 is transmitted to a damper motor 19 so as to drive a damper 18 in the direction to narrow the opening of the damper 18. Accordingly, the opening of the damper 18 is throttled and the rate of circulating air flow is reduced and consequently the temperature of the air blown-off is raised, resulting in preventing passengers near a blow- off grill 37 from feeling chilly and as a result not comfortability is impaired.

Ventilation damper control system

Abstract: A control system for controlling movement of damper blades in a damper housing being open and closed positions consists of a support member having a driving link movable thereon and moved through a drive means. The driving link is biased to a closed position by a spring and is moved to an open position through the drive means, which is disengaged from the driving link through a power-operated member. The drive motor and the power-operated member connected to a power source through an electric circuit which incorporates switches and sensors that will automatically cause the damper blades to close under preselected conditions and a manual-override for remote-control and for manually overriding the temperature-sensing mechanism when desired.

Roll-suppressive control system for automotive suspension system with variable damper

Abstract: The stiffness of a vehicular suspension system is selected in accordance with vehicle speed and the rate of steering adjustment, which influence the centrifugal force on a turning vehicle. Shock absorbers (14) in the suspension system can be operated in either high or low damping force modes. Vehicle speed and steering wheel position are monitored, and the latter property is checked periodically to derive a value of steering wheel acceleration. When steering wheel acceleration, i.e. the second derivative of the steering angle with respect to time, exceeds a theshold value, then shock absorbers are operated in the high damping force mode; otherwise, they operate in the low damping force mode. The threshold value to which the steering wheel acceleration value is compared is derived as a function of vehicle speed. Pivotable, rectangular-cross-section torsion bars or other selectable-stiffness suspension elements may be used in place of the shock absorbers.

The Chatter of Semi-Active On-Off Suspensions and its Cure

Abstract: Semi-active suspensions are those in which otherwise passively generated damper forces are modulated using feedback control and small amounts of control effort. Recently it was discovered that two-stage, ON-OFF, semi-active control would chatter between the ON and OFF states in a manner similar to bang-bang, active control systems. This chatter is dependent upon the switching algorithm. This paper describes the dynamics of this chatter and suggests alternative control policies for its cure.

Hydraulic shock absorbing device of adjustable damping force type

Abstract: A hydraulic shock absorbing device of adjustable damping force type for use in a vehicle such as an automobile includes hydraulic dampers with the damping force thereof being adjustable between at least two, low and high damping force conditions, and a selective switching circuit operable by a driver of the vehicle for selectively determining the damping force condition of the dampers. At least one sensor is provided to detect the operating condition of the vehicle, such as the speed of the vehicle, the position of the gas pedal, the pressure in the braking system or the like, to generate a signal at a predetermined operating condition of the vehicle, and the signal is supplied to a control circuit for switching the dampers to the high damping force condition to override the switching circuit.

The effectiveness of dampers for the analysis of exterior scalar wave diffraction by cylinders and ellipsoids

Abstract: The technique of dampers is now widely used in the numerical analysis of unbounded problems. The dampers are used to absorb the outgoing waves. This paper will consider in detail the best formulations of damper methods. Examples will be given showing the effectiveness of three different dampers, in two dimensional and three dimensional models. The geometries considered are circular and elliptical cylinders, spheres and ellipsoids. The results indicate that dampers are indeed very effective, particularly those of higher order, which have recently been developed by Bayliss et al.1,2 and others.

Combined rotary damper device including a stored energy mechanism and braking mechanism

Abstract: A rotary damper device comprises a base plate, a rotary cylinder rotatably disposed on the base plate through the medium of a damper, and a coil spring interconnecting the base plate and the rotary cylinder. The base plate and the rotary cylinder are interconnected to the main body of a device and the lid of the device. When the lid is opened or closed, the braking force of the damper and the resilient force of the coil spring cooperate to generate effective braking force and enable the opening-closing device to be opened or closed smoothly under the influence of the effective braking force.

Method of controlling an air heater of a coal-fired boiler

Abstract: A method of controlling an air heater of a coal-fired boiler system comprising an air heater for heating a primary air used to dry a pulverized coal and convey it into the boiler and a secondary air to combust the pulverized coal by a heat exchange utilizing the exhaust gas discharged from the boiler as a heat source. The air heater includes a primary air heater and a secondary air heater arranged in parallel and the exhaust gas is introduced therein from the boiler by an induced draft fan with the flow rate of the exhaust gas being introduced into each of the air heaters being controlled by a respective gas damper. The heater primary air is mixed with a cold air to have a suitable temperature to dry and convey the pulverized coal, wherein the opening of the damper for the cold air is maintained at a low value of approximate 0% for maintaining the flow rate of the cold air low, while the suitable temperature is obtained by controlling the gas damper for the primary air heater.

Controlling energy in an air-conditioning system

Abstract: A system for minimizing the energy consumption in a central air conditioning unit incorporating a refrigeration unit which is normally in operation to supplement or substitute for the cooling effect of outside air. The system employs sensor to sense the enthalpy of the return air entering the unit from the work space, the outside air entering the unit from the outside, and the washer air discharged into the work space from the unit, and controls the operation of the unit in accordance with the relative levels of enthalpy at these points. The energy content of the discharged washer air may be modified by modulating dampers controlling the proportion of outside and recirculated air, and also by modulating the washer which provides evaporative cooling and, in addition, cooling by refrigeration. The controls keep the outdoor air dampers normally closed when the enthalpy of the outdoor air is higher than the enthalpy of the return air and keep the outdoor air dampers normally opened when the enthalpy of the outside air is less than the enthalpy of the return air. Regulating means provide auxiliary signals to modulate the dampers to avoid adversely affecting the conditioning effect of the washer air in the work area, and also to enable the continued operation of the refrigeration unit without damage when the system would otherwise call for operating the unit at less than the minimum safe operating load.

Damper for braking rotation

Abstract: A rotation-braking damper comprises a housing formed of a cap and a case, a shaft provided at the external end thereof with a toothed wheel and inserted on the internal end thereof into the housing, a disk fastened to the internal end of the inserted shaft, and a lock washer disposed inside the housing as held in contact with the disk. By the lock washer, the shaft in rotation is braked against the cap. The damper of this invention produces a desired braking effect on an opening-closing object such as a lid. The damper can be constructed with a small number of component parts.

Engine torsional vibration damper

Abstract: The torsional-vibration damper is particularly for absorbing torque fluctuations in an IC engine, having coaxial flywheels turning for a limited amount in relation to each other in opposition to damping equipment. The first turns with the engine and second is coupled to a transmission input member. The second flywheel has a central boss extending axially towards the engine and supported in bearings from the latter. The boss can be arranged to protrude into a central recess in the first flywheel.

An Adaptive Squeeze-Film Bearing

Abstract: This paper examines the effect of controlling the oil supply pressure to squeeze-film bearings in applications where these elements are used to provide damping for a light flexible transmission shaft having an arbitrary unbalance mass distribution. The shaft length and diameter selected for the study are typical of those used for helicopter tail rotor transmissions. A computer simulation is undertaken to study the effect of a squeeze-film damper located at: 1) The end supports. 2) Mid-span with undamped end supports. 3) Mid-span with damped end supports. The simulation shows that in this type of application, good vibration control can be achieved by using a squeeze-film damper which is capable of switching between two levels of damping. The feasibility of attaining such a characteristic is examined experimentally.

Thermal shock chamber

Abstract: A thermal shock chamber comprising a test area, a high-temperature air conditioning unit having a gas outlet and a gas inlet adjacent to the test area, an outside air supplying unit having an air outlet and an air inlet adjacent to the test area, a low-temperature air conditioning unit having a gas outlet and a gas inlet adjacent to the test area, a first damper assembly for opening the outlet and the inlet of one of the high-temperature air conditioning unit and the outside air supplying unit and closing the outlet and the inlet of the other unit at the same time, and a second damper assembly for opening the outlet and the inlet of one of the low-temperature air conditioning unit and the outside air supplying unit and closing the outlet and the inlet of the other unit at the same time.

Dual clearance squeeze film damper

Abstract: This invention relates to a dual clearance hydrodynamic liquid squeeze film damper for a gas turbine engine. Under normal operating conditions the device functions as a conventional squeeze film damper, using only one of its oil films. When an unbalance reaches abusive levels, as may occur with a blade loss or foreign object damage, a second, larger-clearance film becomes active, controlling vibration amplitudes in a near-optimum manner until the engine can be safely shut down and repaired.

Damper and spring shaft support assembly

Abstract: A support assembly for a rotating shaft utilizing an annular spring is disclosed. A series of support rods are spaced on the interior and exterior sides of an annular spring to define spring segments which act as a spring for supporting the journal. A squeeze film damper cavity may be incorporated either as part of the spring support structure or separately within the assembly to provide the necessary damping.

Fuel feed system for an internal combustion engine

Abstract: A fuel feed system of an internal combustion engine, in which for damping fuel oscillations which are excited by the closing of injection valves and which occur amplified in a predetermined rotational speed range, a damper is attached to the distributor pipe opposite to a regulator. The damper is of the same type of construction and size as the regulator and forms together with the same a resonator-antiresonator system, whereby the fuel column oscillates to and fro with low flow losses between the regulator and damper.