Patent Application
20180163890
Poppet valves are a common type of valve typically comprising a plug capable of obstructing a hole, known as a seat. Such plugs may be translated relative to the seat to permit or restrict fluid flowing therethrough. While a variety of mechanisms have been employed to translate such plugs, it is not uncommon for a solenoid switch to fill this role. A conventional solenoid switch may comprise a metal rod disposed within an electrical conductor wound as a helix. When an electrical current is passed through the conductor a magnetic field may be established within the conductor which may translate the rod.
In various applications a plug may require additional initial force before disengaging from a seat. For instance, a plug may stick to a seat due to fluid deposits adhering thereto or high fluid pressures acting on the plug when shut. To free such a plug, U.S. Pat. No. 6,213,446 to Dismon et al. describes a magnetic coil that may be energized to produce a magnetic field, accelerating an armature to build up kinetic energy and impact against a head of a valve rod. In Dismon, when the current is turned off, the armature retracts under action of a spring. In such a manner, the armature “hammers” the valve rod to overcome sticking.
Where valves are used to control fluids comprising particularly high pressures or abrasive particles suspended therein, such fluids may damage the valves by prematurely wearing exposed surfaces. Such wear may be especially pronounced at times when the valve is just barely open due to the higher speeds that may occur through narrow orifices. In order to combat such wear, some valves have incorporated superhard materials, such as polycrystalline diamond (PCD), into their designs. For example, U.S. Pat. No. 8,640,768 to Hall et al. describes diamond coatings or films deposited on valve surfaces. Such diamond may be grown in a vapor deposition process by placing a substrate in an environment that encourages diamond grain growth and exposing the substrate to gases comprising carbon and hydrogen. Hall also describes valve components formed from PCD that may be sintered in a high-pressure and high-temperature press. During such sintering, diamond grains may be mixed with a metal catalyst that lowers the activation energy required to cause the grains to grow and bond to one another.
While such superhard materials may be helpful for erosion resistance, they are also known to be brittle. As stated by U.S. Pat. No. 9,475,176 to Bao et al., “when variables are selected to increase the hardness of the PCD material, brittleness also increases, thereby reducing the toughness of the PCD material.” Consequently, superhard materials that have been used in other types of valves have not been used in hammering poppet type valves.
A hammering poppet valve may comprise a plug receivable by a seat wherein both the plug and seat comprise superhard material. The poppet valve may be designed and operated in such a way so as not to fracture the superhard material as the plug is received by the seat.
Specifically, the poppet valve may comprise a magnetic core translatable within at least one solenoid. Kinetic energy from the translating magnetic core may be transmitted to the plug when the magnetic core impacts an anvil causing the plug to move relative to the seat. The plug may be moved incrementally relative to the seat by a plurality of impacts of the magnetic core in either direction. The plug may be rigidly attached to a guide rod with two anvils affixed thereto spaced from one another along the guide rod. In one embodiment, two axially-spaced coaxial solenoids, formed from a single wire oppositely wound for each solenoid, may accurately and forcefully translate the magnetic core.
The magnetic core 220 may comprise a generally toroidal form such that it may surround and slide over a guide rod 224 passing therethrough. In the embodiment shown, the guide rod 224 extends along a common axis of the first and second solenoids 221, 222 although other arrangements are possible. The guide rod 224 may comprise at least one anvil attached thereto. In this embodiment, the guide rod 224 comprises a first anvil 225 and a second anvil 226 spaced apart from one another along a length of the guide rod 224 with the magnetic core 220 translatable therebetween.
The guide rod 224 may also be attached to a plug 227 receivable by a seat 228. When received by the seat 228, the plug 227 may obstruct fluid 229 from flowing from the at least one inlet 112 through to the at least one outlet 113. To disengage the plug 227 from the seat 228, and therefore allow the fluid 229 to flow, at least one of the first or second solenoids 221, 222 may be excited by passing an electrical current therethrough. This excitement may form electromagnetic fields that may translate the magnetic core 220 and cause it to impact the second anvil 226. Such impact may travel through the guide rod 224 causing the plug 227 to move relative to the seat 228.
Those of ordinary skill in the art will recognize that, while the plug 227 of the embodiment shown is positioned on the same side of the seat 228 as the magnetic core 220, in other embodiments a plug may be positioned on an opposite side of a seat from a magnetic core with a guide rod passing through the seat and achieve similar results.
When excited by an electrical current passing therethrough, each of the first and second solenoids 421, 422 may act as an independent electromagnet. For example, if an electrical current is passed in one direction through first and second solenoids 421, 422, a positive charge 441 and a negative charge 442 may form on opposite ends of the first solenoid 421. Additionally, a separate positive charge 443 and negative charge 444 may form on opposite ends of the second solenoid 422. As can be seen, the positive and negative charges 441, 442 associated with the first solenoid 421 may be reverse from the positive and negative charges 443, 444 associated with the second solenoid 422 due to the reverse winding.
The magnetic core 420 may comprise a negative charge 445 permanently associated with one end thereof and a positive charge 446 permanently associated with an opposite end thereof. When the first and second solenoids 421, 422 are excited in the manner described above, the positive charge 446 and negative charge 445 of the magnetic core 420 may be repulsed by the oppositely aligned positive charge 441 and negative charge 442 of the first solenoid 421 and attracted by the similarly aligned positive charge 443 and negative charge 444 of the second solenoid 422. This combination of repulsion and attraction may urge the magnetic core 420 axially as shown by the arrow 447 in a controlled yet forceful manner.
If the direction the electrical current passes through the first and second solenoids 421, 422 is reversed the positive and negative charges will also reverse, as shown in
To protect the superhard material of the plug 527 and seat 528, which is commonly brittle, from fracture due to such collisions, translation of the magnetic core 520 may be controlled so as to provide a series of smaller impacts against the at least one anvil 525 rather than one large impact. This series of smaller impacts may cause the plug 527 to move incrementally toward the seat 528 and lessen the power dissipated in any one collision. It has also been found that such incremental movement may allow for smaller valve components leading to a smaller valve overall as well as an increased amount of control over the size of a gap between the plug 527 and the seat 528 through which fluid may flow allowing for throttling of the valve.
Whereas certain embodiments have been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present disclosure.
