Browse Topic: Chokes

Items (14)

Fabrication of an Integrated Photonic Waveguide Joint in Micromachined Silicon

TBMG-2425504/01/2016

High-aspect-ratio silicon structures are necessary components in many MEMS (microelectromechanical systems). Aspect ratio is defined as the ratio of the height of the structure to its lateral width. The structures are typically fabricated through bulk micromachining steps such as deep reactive ion etching. In some cases, multiple levels of high-aspect-ratio structures are required. For instance, one may want to etch completely through a silicon wafer to thermally isolate a bolometer or provide waveguide coupling to an antenna defined on an insulating membrane, and at the same time have integrated high-topology structures required for microwave coupling or filtering. Definition of the structures typically uses photolithographic technology. But for high-aspect-ratio structures, spin cast resist becomes difficult to incorporate due to the non-uniform thickness of the resist around tall structures. One can cast very thick layers of photoresist, but this limits the minimum feature size, and

Multipath, Multistage, Erosion-Resistive Valve for Downhole Flow Control

TBMG-2387102/01/2016

Multipath, multistage, erosion-resistant flow control valves have been developed that can sustain the extremely high pressure of deep oil wells. Fitting in the restricted available space and operating using limited power with a long lifetime are challenges for choke valves in the downhole environment of oil wells. These valves must control the flow rate from high-pressure oil reservoirs in the presence of fluids that have non-zero sand concentrations. This design consists of a digitized flow control valve with multipath and multistage pressure reduction structures. Specifically, the valve is configured as a set of parallel flow paths from the inlet to the outlet.

Simulation of Tractor Operation in Threshing Field by Creating a Dust Environment to Study the Operational Behavior of Tractor

2015-26-014501/14/2015

The objective of this project is “Bringing Field to Lab”. Normally in field, tractors are utilized for various applications like harvesting and threshing operation in a dusty environment which consists of paddy, sand, straw etc. These dusts would affect the tractor performance and often cause problem like engine choking at severe condition. Field data on threshing acquired from north Indian places like Jaitsar, Jalandhar where threshing done in summer at a temperature around 50°C. Also during threshing full tractor power is used through (PTO) power take off and this load fluctuates according to manual loading of paddy in thresher. Many iterations are carried out to simulate the real time loading of tractor in lab level and from the results concepts like, a) Forced dust blowing arrangement with spray quantity control - Simulates Threshing environment, b) Room heaters with controllers for maintaining room temperature-Simulates North India environment, c) DYNO arrangement for PTO loading

Arthanathan, Sankaranarayanan

Hydraulic High-Pressure Valve Controller Using the In Situ Pressure Difference

TBMG-20954

11/01/2014

Various applications exist where high-pressure valves are required, but the problem for control of such valves lies in that they have to move against a strong pressure differential that may require significant force, energy, and large actuators. The solution to this problem is to take advantage of the in situ pressure differential to operate valves by opening small valves to change the pressure on either chamber of a hydraulic cylinder that is connected to the valve’s moving element.

Analyzing 6-Pulse Drive Harmonic Mitigation Techniques for Industrial Automation

TBMG-20651

10/01/2014

Contemporary industrial automation control systems are employing variable frequency drives (VFDs) in ever-increasing numbers. VFDs give control engineers flexibility to precisely regulate the speed and torque of motors in a wide array of applications. The proliferation of these VFDs has brought increased attention to harmonic distortion created by these drives and their effects on the power system. A standard-pulse drive with no built-in harmonic mitigation controls may interfere with neighboring equipment, reduce equipment life, and create a serious negative impact on the quality of utility power. Looking at the theory of operation for the following harmonic mitigation techniques and their typical performance levels may help take the guesswork out of harmonic reduction for these power systems.