523 results about "Compression system" patented technology

The invention provides a water working medium quasi-saturated compression high-temperature heat pump system based on an ejector, and belongs to the field of compression heat pumps. The problems that after an existing compression system flows through a throttling valve, the superheat degree of steam exhaust is large due to high-temperature lift compression, and the loss of available energy in the throttling process from condensate to a two-phase region is too large are solved. A multi-stage spraying atomization structure is adopted, a micro-nano liquid drop mist flow with the particle size controllable to be 50-200 nm and the liquid mass fraction adjustable to be 5%-10% is formed before compression, the airflow humidity regulation and control precision is remarkably improved, the quasi-saturation compression process is matched, and the thermal matching performance and the energy efficiency level of a system are effectively improved; a main flow inlet of the jet atomizer is changed into a compressor outlet from a condenser outlet, so that the response speed is increased, and meanwhile the jet atomizer is suitable for a complex variable-working-condition system; or single-stage compression is optimized into a two-stage compression form, so that higher heating temperature and more stable system operation are realized; or liquid from a lower-pressure position is injected, so that the injection capacity is improved.

The invention relates to the technical field of transformers, in particular to an anti-interference phase-shifting rectification dry-type high-capacity transformer which comprises a cooling channel, an air inlet system, an air outlet system and a compression system. The cooling channel is arranged between the high-voltage coil and the low-voltage coil; the air inlet system is connected with the mounting frame, and when the air inlet system works, low-temperature gas outside the anti-interference shell is sucked in, forms rotational flow and is fed into the cooling channel; the air outlet system is connected with the top of the anti-interference shell, and the compression system is connected with the air outlet system; low-temperature air is extracted from the outside and fed into the space between the high-voltage coil and the low-voltage coil in a rotational flow mode, dead-corner-free heat dissipation is guaranteed, the heat dissipation efficiency can be improved by changing the included angle between the low-temperature air and the horizontal plane during rotational flow along with heat change, heat is recycled for refrigeration, and the heat dissipation efficiency is further improved; the problem that due to heat accumulation in the anti-interference shell, air blown into the position between the high-voltage coil and the low-voltage coil by the draught fan is hot air and is not evenly distributed is solved.

The invention provides a combustion drive circulating gas-lift pressurizing all-in-one machine, and belongs to the technical field of natural gas production. Comprising a pressurization exhaust system, a gas lift pressurization system, a sewage discharge system, a pressure stabilizing system, a combustion drive multi-stage compression system and a base, and the pressurization exhaust system, the gas lift pressurization system, the sewage discharge system, the pressure stabilizing system and the combustion drive multi-stage compression system are all installed on the base. By arranging the pressurization exhaust system and the gas lift pressurization system, the device can perform gas lift and pressurization operation in an oil field, one machine has two purposes, by arranging the combustion drive multi-stage compression system, efficient dispatching of an oil and gas field circulation gas lift pressurization site is achieved, powerful guarantee is provided for development of the dual-carbon industry, and meanwhile, the device has good application prospects. By arranging the purification assembly, the natural gas in the well rises, so that the purity of the extracted natural gas is improved, and the problems that an existing gas lifting and pressurizing all-in-one machine is high in use cost and poor in effect are solved.

Examples of a plasma compression system are disclosed. The system includes a metallic vessel configured to receive and contain a plasma. The system further includes a metallic liquid liner in the vessel and at least partially bounding a plasma compression region having a longitudinal axis, and means for moving the liquid liner inwardly towards the longitudinal axis to compress the plasma in the plasma compression region. The system further includes a plurality of electrically conductive coils outside the plasma compression region and configured to generate a poloidal magnetic field in the liquid liner and the plasma compression region. At least some of the poloidal magnetic field within the plasma compression region extends along the longitudinal axis, and at least some of the poloidal magnetic field in the liquid liner moves inwardly towards the longitudinal axis with the liquid liner as the liquid liner moves towards the longitudinal axis.

The invention discloses a turbine for testing, an engine testing device and a method for determining a pneumatic instability boundary of a compression system, which can determine the pneumatic instability boundary of the compression system in a complete machine environment, do not cause extra burden to the turbine and compression system components, and do not need to modify a tester and surrounding equipment on a large scale. The turbine for testing is used for replacing an original turbine in a complete machine surge test of an engine, and the engine testing device is used for the complete machine surge test of the engine. Stator blades of the test turbine are arranged to be rotatable blades, so that the circulation sectional area of the test turbine is reduced by rotating the stator blades, and the compression system can enter a surge state.

The invention discloses a compressor system and a method for realizing stable boundary control of a gas compressor thereof, which can actively adjust parameters B of the system and realize switching of an instability mode of the gas compressor between surging and rotating stall by only depending on an independent, small and adjustable switching section on the premise of not modifying large basic hardware (such as a volute and a pipeline). According to the principle of the compressor system provided by the embodiment of the invention, the effective flow area is changed by adjusting the angle of the turbine guider, so that the stability boundary of an upstream gas compressor or a fan is actively expanded, low-cost and rapid adjustment of the stability of the gas compressor is realized, the research and development efficiency is improved, and the test period is effectively shortened. The compressor system provided by the embodiment of the invention has the characteristic of wide applicability, can be applied to an independent compression system part test environment, and can also be applied to a complex complete machine environment comprising a compression system.

The invention discloses a steam compression system and a control method thereof. The steam compression system comprises a flash tank, at least one stage of steam compressor and a first water circulation pipe. The flash tank is used for enabling the steam generation water heated to the specified flash temperature to be subjected to flash evaporation under the negative pressure condition in the tank to become low-pressure steam; the steam compressor is used for compressing the low-pressure steam into superheated steam of which the saturation pressure is target condensing pressure; and the first water circulating pipe is used for guiding water of a target water source to motors of the steam compressors at all levels and exchanging heat with heat dissipation mechanisms of all the motors, and the water subjected to heat exchange returns to the target water source. Compared with the prior art, heat at the motor is recycled through water circulation, so that the enthalpy value of water for steam generation is increased, energy consumption needed by steam generation is reduced, and the comprehensive energy efficiency of the system is improved.

The invention discloses a gas TPSA compression interstage purification integrated device control system and method. The system comprises a gas compression unit, an adsorption purification unit, a regeneration gas treatment unit and a control unit. The gas compression unit comprises a gas inlet pressure stabilizing valve, a gas compressor preceding stage, an interstage gas-gas heat exchanger, a compressor backward stage, an interstage pressure control valve and a backflow control valve, wherein the gas compressor preceding stage is used for pressurizing low-pressure raw gas and backflow regenerated gas to the pressure required by purification; compression heat of the interstage gas heat exchanger is used for preheating regenerated gas; the rear stage of the gas compressor is used for pressurizing the purified raw material gas to the pressure required by the downstream; the technical problems that a traditional TPSA gas purification device needs at least two compressors for staged compression, purification and compression systems are high in energy consumption, and loads are not easy to adjust are solved.

The invention discloses an acoustic monitoring method, system, medium and equipment for the near stall condition of an aircraft compressor, and the method comprises the steps: carrying out the synchronous collection of sound pressure time domain signals of multiple channels of an aviation compression system; adding a rectangular window to the multi-channel sound pressure time-domain signal, and constructing an acoustic time-domain signal segment to monitor the current operation state of the aviation compression system; performing fast Fourier transform on the multichannel acoustic time domain signal segment in the current time domain window to form a plurality of sound pressure frequency spectrums, judging whether a plurality of single-tone characteristic frequencies which are non-integer multiples of the current rotation frequency exist in the sound pressure frequency spectrums or not, and constructing an orthogonal Fourier transfer matrix based on the installation position and the highest circumferential modal order, and judging whether the order difference of the characteristic acoustic mode under each characteristic frequency is the rotation frequency multiple difference of the corresponding characteristic frequency, calculating the acoustic mode amplitude corresponding to each broadband frequency component, drawing an acoustic mode spectrogram, and judging whether a mode bright band exists at the cut-off frequency boundary in the acoustic mode spectrogram.

This application relates to a performance test system and method for a self-circulating steam compressor. Specifically, the system includes a steam input system, a steam compression system, a buffer and storage system, a steam recovery system, and an intelligent control system, as well as an optional steam compressor makeup water system, a condensate recovery system, and an internal oil cooling system. The self-circulating steam compressor performance test system described herein only requires a small amount of external steam to be input at the initial startup stage. After reaching a stable state, it can achieve full self-circulation operation. This reduces steam consumption, improves the overall economy and energy utilization rate of the system, and has strong operating reliability.

The invention belongs to the technical field of compressors, and provides a compressor and a compression system. The compressor comprises a machine shell assembly, wherein a containing part is formed in the machine shell assembly; the rotor assembly comprises a female rotor and a male rotor which are meshed with each other, and the rotor assembly is positioned in the accommodating part; and the sliding block assembly is arranged in the containing part, and the sliding block assembly can move in the radial direction of the rotor assembly so as to adjust the opening degree of an axial exhaust port of the compressor and the opening degree of a radial exhaust channel. According to the compressor, the compression ratio of the compressor can be flexibly adjusted, meanwhile, the flowing loss of the axial exhaust port with the fixed size in a medium-low pressure mode is avoided, the working efficiency of the compressor is improved, the exhaust pressure is guaranteed, and meanwhile the gas flow is also guaranteed.

The invention discloses a power grid primary frequency modulation control model based on large-scale compressed air energy storage power generation, which is used for carrying out key technical research by adopting a research method combining current situation investigation, theoretical analysis, simulation calculation, database establishment, numerical simulation, test verification, development of process parameters and summarization and induction. And finally, an own compressed air energy storage technology is formed and popularized to practical engineering application. Through the complex heat exchange system, the turbine system, the heat storage system, the compression system and the like which are complex in characteristics and mutually coupled, the influence on the power grid in different operation modes of energy storage and energy release is studied and mastered, through theoretical research and numerical simulation, the response time of the energy storage power station is shortened as much as possible, the fastest load response speed is achieved, and the energy storage and energy release efficiency is improved. And requirements of power grid frequency modulation and peak regulation are satisfied.

A compression system comprising a compressor, the compressor comprising a sealing arrangement including at least one gas seal. A gas leakage recovery line is adapted to recover process gas leakages from the at least one gas seal. A fuel cell arrangement is fluidly coupled to the gas leakage recovery line. The fuel cell arrangement is adapted to process gas leakages and generate electric power therefrom.

The utility model discloses a multi-stage compression gas compression system which comprises a hydraulic driving unit with fixed displacement, a multi-stage compression cylinder, a gas storage device, a gas pressure detection unit and a control unit, the multi-stage compression cylinder comprises a plurality of compression cylinders which are sequentially connected in series from the first stage to the last stage through gas conveying pipelines. The signal output end of the air pressure detection unit is connected with the signal input end of the control unit. The air pressure detection unit is used for detecting air pressure signals of the multi-stage compression cylinder and sending the air pressure signals to the control unit. And the control unit is used for controlling the working states of the other stages of compression cylinders except the first-stage compression cylinder in the multi-stage compression cylinders according to the air pressure signal, so that the other stages of compression cylinders except the first-stage compression cylinder in the multi-stage compression cylinders are put into compression work or quit compression work. According to the utility model, the cost and the control complexity of the gas compression system can be reduced, and the efficiency improvement and consumption reduction of the gas compression system can be realized.

The invention relates to a vehicle-mounted screw air compressor oil emulsification prevention method and system, a medium and a program product, and in the method, the running state parameters of a screw air compressor are monitored in real time, and a water vapor saturation pressure formula and a temperature and pressure coupling mathematical model are used for calculating saturation water vapor pressure and actual water vapor partial pressure respectively. When the actual water vapor partial pressure is larger than the saturated water vapor pressure force corrected by the safety coefficient, the system adjusts the oil way temperature control valve to reduce the lubricating oil flow of the oil cooler so as to increase the exhaust temperature. If the condensation risk still exists and the exhaust temperature does not reach the shutdown protection threshold value, the oil way temperature control valve continues to be adjusted; if the exhaust temperature reaches the shutdown protection threshold value, the actual water vapor partial pressure is reduced by reducing the rotating speed of the frequency converter. And after the condensation risk is eliminated, the current operation parameters are maintained. The method is used for reducing the possibility that water vapor reaches saturation in the compression system and liquid water is separated out, and the accuracy and stability of lubricating oil emulsification risk control of the air compressor under the variable load working condition are improved.

The invention discloses a rapid calculation method for flow field prediction of a compression system of a variable cycle engine, and the method comprises the steps: building a parameterized mapping model of valve opening and total pressure distribution based on a wall attachment turbulent jet theory; the fan state conversion process is dispersed into a plurality of quasi-steady-state working conditions according to the actuation angle range of a mode selection valve; constructing a total pressure distribution and recovery coefficient prediction module under each working condition by using the parameterized model; the prediction module is embedded into a fluid mechanics solver in the form of boundary conditions, numerical simulation of the state transition process is completed, and performance change data are obtained. According to the scheme, full-three-dimensional complex calculation is replaced by parameterized mapping, the efficiency and precision of variable circulating fan mode conversion performance analysis are remarkably improved, meanwhile, the calculation cost is reduced, and quick-response technical support is provided for compression system optimization design.

A method and apparatus for controlling compressors in a cascade vapor compression system. The process may include controlling the operation of a first compressor based on a constant band control, and controlling the operation of a second compressor based on a proportional band control. Controlling the first compressor based on the constant band control may include operating the compressor at a constant setting if first measurements are within a range associated with a first setpoint. It may also include proportionally adjusting the operation of the first compressor if the first measurements are outside the range. Further, controlling the second compressor based on the proportional band control may include operating the compressor based on one of a plurality of proportional bands, each proportional band having a different proportional factor. Controlling the second compressor operation may further include switching between these proportional bands based on a second measured parameter.

The invention discloses a gas and heat combined supply compression system operation optimization method based on energy efficiency evaluation, and relates to the technical field of heat supply system operation optimizing.Distributed sensors are deployed at equipment and pipeline nodes of a gas and heat combined supply compression system, and operation data of equipment and pipelines of the gas and heat combined supply compression system are collected in real time through the sensors; the operation data comprises equipment and pipeline node inlet and outlet temperature, pressure, flow, power consumption and operation state parameters of the gas and heat combined supply compression system. The operation data of the gas and heat combined supply compression system is collected in real time, a multi-dimensional dynamic energy efficiency evaluation model is constructed by using the operation data, core indexes such as waste heat recovery efficiency and waste heat utilization matching degree are accurately quantified, and accurate mastering of waste heat supply and demand states is achieved. The problem that waste heat supply is wrongly matched with actual heat requirements is effectively solved, and the effectiveness of waste heat recovery is improved.

The utility model relates to the technical field of cleaning equipment, in particular to an MVR evaporator which is provided with an evaporator body, the evaporator body is provided with a stock solution inlet pipe, a condensate water outlet pipe and a water vapor compression system, the stock solution inlet pipe is provided with a heat exchanger, the condensate water outlet pipe is provided with a condensate water tank, and the condensate water tank is provided with a heating jacket. The heat exchanger is used for recovering the heat of the condensed water in the condensed liquid outlet pipe and preheating the stock solution, so that the effective utilization of energy sources and the improvement of the evaporation efficiency are realized; through recycling of the water vapor compression system, the MVR evaporator remarkably reduces the requirement for external steam, and therefore energy is saved; by arranging the condensate water tank and the heating jacket of the condensate water tank, a necessary initial steam environment is provided for the evaporator in the starting stage, the starting process of the evaporator is accelerated, and the overall operation efficiency is improved.

The invention provides a cooling device, a control method, a compression system and an air conditioner, the cooling device comprises a cooling unit and a vacuum pump, the cooling unit comprises an oil storage tank and an oil conveying tank, an oil inlet and an exhaust port are formed in the upper end of the oil conveying tank, and an oil outlet is formed in the lower end of the oil conveying tank; the oil inlet pipeline communicates with the oil storage tank and the oil inlet. The exhaust pipeline communicates with the vacuum pump and the exhaust port. Under the action of the vacuum pump, air in the oil conveying tank is exhausted, so that negative pressure is formed in the oil conveying tank; under the action of negative pressure, cooling oil in the oil storage tank enters the oil conveying tank through the oil inlet pipeline, and then the cooling oil in the oil conveying tank is output through the oil outlet pipeline; the scheme that the vacuum pump replaces a traditional oil pump is adopted, cooling oil in the oil storage tank is input into the oil conveying tank through negative pressure, then the cooling oil is output through gravity, and conveying of one or more kinds of cooling oil is achieved; due to the characteristic of negative pressure driving, the device is not influenced by the viscosity of cooling oil and can be compatible with cooling oil with different rheological characteristics; when cooling oil is replaced, only the oil conveying tank and the corresponding pipeline need to be cleaned.

The invention provides a double-shaft compression system supporting structure suitable for a large-mass long shaft system, and belongs to the technical field of aero-engines, the double-shaft compression system supporting structure comprises a main support, a rear auxiliary support and a front auxiliary support, the main support is connected with an exhaust force bearing casing of a double-shaft compression system and used for transmitting part of weight of the double-shaft compression system to the main support, and the rear auxiliary support is connected with the front auxiliary support; the rear auxiliary support is connected with an intermediate force-bearing casing of the double-shaft compression system and used for transmitting the weight of the intermediate force-bearing casing of the double-shaft compression system to the rear auxiliary support, and the front auxiliary support is connected with an air inlet force-bearing casing of the double-shaft compression system and used for transmitting the weight of the air inlet force-bearing casing of the double-shaft compression system to the front auxiliary support. The technical problem that a traditional single-fulcrum supporting structure cannot stably position and absorb thermal expansion deformation is solved, and long-time stable supporting of a large-mass long-shafting biaxial compression system in a biaxial compressor tester in a high-temperature working environment is achieved through the three-fulcrum supporting structure.

The invention provides an automobile damping spring compression rigidity detection device which comprises a spring feeding control system, a spring compression system, a spring deformation detection system, a spring discharging screening system, a digital control system and a rack. The spring feeding control system comprises a spring, a spring supporting plate, a side plate adjusting mechanism, a first blocking mechanism and a second blocking mechanism, the spring compression system comprises a rotary base mechanism, a spring radial positioning mechanism and a main pressing mechanism, and the spring deformation detection system comprises a push rod motor mechanism, a detection supporting plate mechanism, a deformation detection mechanism and a discharging port. The discharging screening system comprises a discharging supporting plate, a first discharging mechanism, a second discharging mechanism and a qualified product box, compression strength ultimate pressure detection and fatigue durability detection can be carried out on springs of different sizes at the same time, and screening is carried out on the deformation of the compressed springs in different interval ranges.

The invention provides a system of a pumped storage coupled compressed air energy storage underground gas storage with an air cushion type surge shaft and an operation method. The system comprises a compressed air energy storage system and a pumped storage system. The interior of the water-gas co-containing bin is divided into an upper-layer gas storage chamber and a lower-layer water storage chamber through a flexible material. The air inlet end of the compression system is communicated with the second air path; the air outlet end of the compression system is connected to the air inlet of the upper-layer air storage chamber through a first air path; a first air valve is mounted on the first air path; a gas outlet of the upper-layer gas storage chamber is connected to the expansion unit through a third gas path, and a second gas valve is mounted on the third gas path; and a detection sensor is mounted in the water-gas co-containing bin. The stability and economical efficiency of the compressed air energy storage are improved, the compressed air utilization rate is increased, the combined operation mode of compressed air energy storage and pumped storage is simplified, the combined dispatching mode of novel energy storage is optimized, and then the safety and reliability of pumped storage are improved.

A vapor compression system includes a primary loop, an auxiliary loop, and first and second valves. The primary loop includes an indoor heat exchanger, an outdoor heat exchanger, and a compressor. The first valve is positionable in first and second positions, such that the first valve fluidly connects the indoor heat exchanger to the compressor in the first position. The second valve is positionable in third and fourth positions, such that the second valve fluidly connects the indoor and outdoor heat exchangers in the third position. The auxiliary loop includes a thermal storage unit, a supply duct, and a return duct. The supply duct fluidly connects a thermal storage unit exit to the indoor heat exchanger when the first valve is in the second position. The return duct fluidly connects a thermal storage unit inlet to the indoor heat exchanger when the second valve is in the fourth position.

The invention relates to a gas-water curtain partition type smoke control system, and belongs to the field of tunnel fire prevention and control, the gas-water curtain partition type smoke control system comprises a tunnel, smoke control partitions, a tunnel fire extinguishing system, a gas curtain generation system, a water curtain generation system and a fire detection alarm, the tunnel is divided into a plurality of smoke control partitions by the gas curtain generation system and the water curtain generation system, and the gas curtain generation system further comprises an ejector. An inlet and an outlet of the ejector are connected with different smoke control subareas respectively, and air in the smoke control subareas where no fire occurs is induced to enter the smoke control subareas where the fire occurs to form an air curtain. Through the air pump, the air pressure tank, the automatic drainer, the safety relief valve and other parts, compressed air is provided and exhausted through the air curtain air opening to form an air curtain, in order to reduce the air supply amount of the air compression system, an ejector mode is adopted, one inlet of the ejector is connected to the smoke control subarea far away from the outlet, and the other inlet of the ejector is connected to the smoke control subarea far away from the outlet. And the cost and the complexity of the system are reduced.

A method and device for determining a pneumatic instability boundary of a compression system in a complete machine environment, the method is applied to an engine test device, the engine test device comprises an engine body and a test modified turbine with a variable circulation sectional area, and the engine body comprises the compression system. The method comprises the steps that a compression system is controlled to enter a surge state by adjusting the circulation sectional area of a refitted turbine for testing and combining a fuel oil step method, or the compression system is controlled to enter the surge state by adjusting the circulation sectional area of the refitted turbine for testing and combining a high-pressure gas filling method; and determining an instability boundary point of the engine test device, and determining a pneumatic instability boundary of the compression system at the current rotating speed according to the instability boundary point. Therefore, the pneumatic instability boundary of the compression system in the whole machine environment is determined on the premise of not increasing the additional burden of a turbine and compression system components.

A thermal management system for an aircraft includes a thermal bus including one or more first heat sources; a heat sink; a vapour compression system including a compressor, a condenser, a receiver, a first side of a recuperator, an expansion valve, an evaporator, a second side of the recuperator, and the compressor; and one or more second heat sources. A heat transfer fluid transfers waste heat energy generated by the first heat sources to the heat sink. A second flow of waste heat energy from the second heat source(s) is transferred to a refrigerant. A third flow of heat energy in the refrigerant is transferred to the heat transfer fluid. The compressor includes a supplementary refrigerant reservoir, and the volume of refrigerant in the vapour compression system is increased during operation when a temperature of the heat transfer fluid is at or below a temperature of the second heat source(s).

Embodiments herein relate to a backpack with a system of one or more locks and cinch lines to provide compression and / or expansion functions, gear stowage, and / or gear access without having to take the backpack off. The compression system allows the user to perform side-to-side and / or front-to-back compression of the backpack by adjusting a tension provided by the cinch lines. The cinch lines and their associated locks, such as friction-type locks, may be accessible at an external location of the backpack, such as near the top or bottom of the backpack, on a hip belt or shoulder strap, to allow for adjustments without interrupting the user's activity. The adjustments can improve comfort and safety by adjusting the center of gravity, reducing movement of the backpack, and stowing objects more securely.

The invention discloses a compression system end area flow regulation and control method based on blade inner cooling under a low Reynolds number. Firstly, through calculation or measurement, a compression system end area three-dimensional flow field under different Reynolds numbers is obtained, and the end area loss variation degree is quantified. Then, revealing regulation and control rules of different isothermal cooling wall surface conditions on near-wall fluid physical property parameters, boundary layer growth rate and end region secondary flow migration intensity under a low Reynolds number, and establishing a correlation model of end region loss reduction and efficiency improvement and wall surface cooling intensity; and on the basis, a blade built-in convection cooling channel structure is designed, the cooling channel and blade surface flow heat characteristics are analyzed based on a conjugate heat transfer method, and inner cooling channel structure parameters are optimized until the wall surface temperature drop amplitude meets the preset requirement. And finally, checking the wall surface cooling effect, and measuring end region performance parameters during inner cooling regulation and control under a low Reynolds number to complete scheme verification. By introducing blade inner cooling, the flow characteristic of an end region can be remarkably improved on the premise that the structural complexity is not increased as much as possible, and stable and efficient operation of a compression system under the low Reynolds number is guaranteed.

To provide a control device, a compression system and a control method capable of reducing an execution frequency of oil return operation.SOLUTION: A control device comprises a control unit that, when turning on or off a solenoid valve provided in a circuit that returns oil discharged from a compressor together with a refrigerant to the inside of the compressor according to an amount of oil inside the compressor, turns on the solenoid valve when the amount of oil is equal to or less than a first threshold, and turns off the solenoid valve when the amount of oil is equal to or larger than a second threshold that is larger than the first threshold and a time that has elapsed since the solenoid valve was turned on exceeds a minimum on time.SELECTED DRAWING: Figure 1