Patent Application
20200149527
The present invention relates generally to a gas compressor installation which includes a start-up valve that reduces the amount of required power for starting up the gas compressor.
Compressor installations may include a motor, a gas compressor driven by the motor, and a storage tank to store gas that has been compressed by the gas compressor. The motor may be an electric motor, an internal combustion engine, or another type of motor. The gas may be air or another gas. The compressor may be a reciprocating piston compressor, a centrifugal compressor, a scroll compressor, a screw compressor having male and female compressor elements, or another type of compressor. The storage tank may be a canister, reservoir, or other type of tank, that contains the compressed gas until it is used to power a device such as a tool, or used by an end user, or released to atmosphere. In most cases, air is drawn into an inlet air side of the gas compressor from atmosphere, and then mechanically compressed, e.g., via pistons or male and female rotors, into a smaller volume in the compression chamber of the gas compressor. The compressed gas flows through a pipe or the like, to the storage tank. As the compressed air is used from the storage tank by the end user, the compressor may be operated to maintain a set pressure. The load on the motor driving the compressor will depend on a number of factors, such as user demand, backpressure, start-up etc.
For example, in a reciprocating compressor, which is widely used in various industrial and domestic applications, the motor is used to drive a pulley to drive a crankshaft that moves piston(s) in a reciprocating manner, where gas enters the suction side, typically through an inlet manifold, is compressed via the piston(s) being driven in a reciprocating manner, and then discharged at high pressure into a tank.
However, when a reciprocating compressor is started, a maximum amount of power is consumed by the motor to start the reciprocating compressor. Electric motors have an inrush current when first started and the power required to bring a reciprocating compressor from standstill, e.g., stopped, to full speed is the greatest when starting the reciprocating motor from stoppage. This is at least because the reciprocating compressor is compressing air as it is started, which adds to the power required for start-up. In order to decrease the amount of power required for starting up the reciprocating compressor and reduce the load on the motor, the compressor can be unloaded so that the compressor is not pumping up the residual air pressure in the system, e.g., having to compress the compressed air which is at a higher pressure than atmospheric.
While there have been several methods used to unload a reciprocating compressor, such methods typically require specific compressor designs or use solenoid valves with timer relays to accomplish this unloading, which adds large and significant costs to the compressor and/or design of the system.
In view of such drawbacks of the known methods, there is a need to provide a simpler, smaller, and more cost-effective structure for unloading a compressor for start-up.
The present invention is provided to solve the deficiencies of the prior art by providing improvements over the prior art. It is an object of the present invention to provide a start-up valve that is an improvement over the prior art in several ways, at least because it costs less than a compressor design that has a specific unloading configuration, is much smaller, and can be attached directly to the compressor discharge of any compressor, e.g., discharge of a reciprocating compressor.
The present invention has no requirement for a specific compressor design for a special unloading method, but rather uses a start-up valve that can be used to divert the discharge of the compressor to atmosphere, thereby reducing the load on the motor at start-up. After starting-up the compressor, a short delay can be used after which the discharge to atmosphere is closed and the compressor resumes normal compression.
In one embodiment of the invention, the start-up valve comprises a valve body having an inlet, an internal passageway, and an outlet; a valve plunger connected at the inlet of the valve body; and a spring provided within the internal passageway and connected to the valve plunger. The start-up valve is configured so that when the spring is in a relaxed state (e.g., having a longer length than in a compressed state), the valve plunger is positioned away from the internal passageway to allow gas to flow around or through the valve plunger and through the valve body. As the compressor starts-up and gas flow increases, the spring is compressed until the valve plunger abuts the internal passageway which seals the inlet of the valve body and the gas no longer flows through the valve body.
When such a compressor is shut-down, the spring returns to the relaxed state and forces the valve plunger away from the internal passageway to allow gas to flow around or through the valve plunger and valve body to unload the compressor.
In another embodiment of the invention, the invention includes a compressor and a start-up valve that comprises a valve body having an inlet, an internal passageway, and an outlet; a valve plunger connected at the inlet of the valve body; and a spring provided within the internal passageway and connected to the valve plunger. The start-up valve is configured so that when the spring is in a relaxed state during a start-up of the compressor, the valve plunger is positioned away from the internal passageway to allow gas to flow around or through the valve plunger and the valve body. After the compressor starts-up and gas flow/pressure increases, the spring is compressed until the valve plunger abuts the internal passageway which shuts-off and seals the inlet of the valve body so that the gas no longer flows through the valve body.
The features and objects of the present invention are more clearly understood from the detailed description taken in conjunction with the accompanying drawings, in which:
In the various figures, similar elements are provided with similar reference numbers. It should be noted that the drawing figures are not necessarily drawn to scale, or proportion, but instead are drawn to provide a better understanding of the components thereof, and are not intended to be limiting in scope, but rather provide exemplary illustrations.
The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto and can be combined interchangeably with certain features in the different embodiments.
The start-up valve 200 is provided at the discharge 14 of the compressor 10, where the start-up valve can be attached directly at the outlet of the compressor or attached to a tubing connected to the outlet of the compressor. The start-up valve 200 can be connected by screw-fitting, compression fitting, bolted, welded, or other fastening means for connecting the start-up valve to the outlet of the compressor or the tubing. A check-valve may be provided between the start-up valve 200 and a storage tank to allow the discharge of gas through the start-up valve 200 without affecting the pressure in the storage tank.
The valve plunger 220, retaining ring 250, and O-ring 260 are provided within the chamber 213. Specifically, the retaining ring 250 is provided within engagement slots provided along the walls of the chamber 213 and below the valve plunger 220 and can be made from metal, carbide, hard plastic, or the like to be able to retain the valve plunger 220 within the valve body 210 of the start-up valve 200. The valve plunger 220 includes a body, plunger, and slots through or around the body of the valve plunger 220 and positioned so that the plunger of the valve plunger 220 is slidably engageable with the passageway 216 of the valve body 210. The O-ring 260 is provided within a seat of the body of the valve plunger 220 which has a diameter greater than a diameter of the passageway 216. The O-ring may be a sealing gasket or the like.
Connected to the plunger of the valve plunger 220 is a spring 240, which is provided within the passageway 216. One end of the spring 240 engages with the body of the valve plunger 220 and the other end engages with the adjustment bolt 230. The adjustment bolt 230 allows the adjustment of the amount of gas flow through the start-up valve 200 (which can increase or decrease back pressure) by adjusting the tension on the spring 240, e.g., the adjustment bolt 230 can be threaded to compress the spring 240. That is, the adjustment bolt 230 provides a means to set different levels of gas flow through the start valve for different sized compressors. It is also appreciated that different springs can be used with different elasticities and spring constants for different sized compressors.
At the outlet 214 of the valve body 210, the muffler 270 is provided, which can be attached to the valve body 210 by a screw fitting within the passageway 216, welded, glued, or by other fitting or fastening means for attaching the muffler 270 to the valve body 210. The muffler 270 discharges gas to the atmosphere and preferably includes a soft porous material which is commonly used with air-powered tools to reduce noise and filter exhaust fumes and can include a support, O-rings, tube stem that is inserted into the passageway, or other similar structure. For example, gas flows through a passageway within the muffler 270 and discharged through the soft porous material to the atmosphere.
As seen in
As seen in
The operation of the start-up valve is as follows (with reference to
Similarly, when a compressor is shut-down, as the pressure in the compressor system is decreased, e.g., due to the compressor being shut down or pressure in the receiver is released where no check-valve is included or pressure is bled out of the discharge side of the compressor, the spring 240 returns to its relaxed state which forces the valve plunger 220 (and O-ring 260) away from the internal passageway to allow gas to flow around the valve plunger 220 and valve body 210 and exit out of the muffler 270. This action unloads the pressure in the compressor to allow a loadless start-up of the compressor, as necessary. The spring in the relaxed state has a longer length than the spring when the spring is in a compressed state, e.g., the spring is compressed with increased compressor pressure and relaxed with decreased compressor pressure.
In view of such structure and features, the present invention solves the deficiencies of the prior art by providing a loadless start-up valve for a compressor installation which is able to discharge compressor pressure for a loadless start-up of the compressor. This is an improvement over the prior art in several ways. These features cost less than a compressor designed in a special way for unloading or that uses a solenoid valve for unloading. The present invention also provides a smaller sized device for unloading that can be attached directly to the compressor discharge, e.g., by a screw fitting.
The invention discussed herein is directed to specific embodiments, but the design is not limited to the description of the exemplary invention but only by the scope of the appended claims. As a result, there are multiple embodiments that employ the beneficial characteristics of the invention, each providing a different advantage and which are combinable and/or interchangeable with various aspects of the different embodiments of the invention that do not depart from the spirit and scope of the invention.
This application claims the benefit of provisional application No. 62/767,106, filed Nov. 14, 2018, the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62767106 | Nov 2018 | US |
