Patent Publication Number: US-2022213970-A1

Title: Combination regulator valve

Description:
CROSS-REFERENCE 
     This application is a continuation of U.S. patent application Ser. No. 16/648,148, filed on Mar. 17, 2020, which is a national filing of PCT Patent Application No. PCT/CN2017/103667, filed on Sep. 27, 2017. The contents of these prior applications are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure generally relates to a valve that may be configured to convey cryogenic fluid. 
     BACKGROUND 
     Cryogenic fluid is often stored in a pressurized tank. The pressure may fluctuate due to temperature variations, filling of the tank, or dispensing of fluid from the tank. The tank may include a one or more valves for (a) regulating pressure of the tank and (b) enabling fluid to be dispensed from the tank. 
     SUMMARY 
     This application is defined by the appended claims. The description summarizes aspects of exemplary embodiments and should not be used to limit the claims. Other implementations are contemplated in accordance with the techniques described herein, as will be apparent upon examination of the following drawings and detailed description, and such implementations are intended to be within the scope of this application. 
     In an embodiment, a valve for conveying fluid disclosed herein comprises a bonnet, a body, a flexible diaphragm, a first spring, and a spindle unit. The spindle unit comprises a pin, a first seat disc, and a seat screw. The bonnet is secured to the body. The flexible diaphragm is compressed between the bonnet and the body. The first spring is disposed in the bonnet. The spindle unit is disposed in the body. The first seat disc is disposed between the pin and the diaphragm. The first seat disc and the pin define a first void. The first spring biases the diaphragm toward the first seat disc. The seat screw is engaged with the body and is slidably engaged with the pin. The seat screw and the pin define a fluid passage in fluid communication with the first void. 
     In another embodiment, a valve for conveying fluid comprises a bonnet, a body, a flexible diaphragm, a first spring, and a spindle unit. The bonnet is secured to the body. The body defines a first port, a second port, and a third port. The flexible diaphragm is compressed between the bonnet and the body. The first spring is disposed in the bonnet. The spindle unit is disposed in the body and comprises a pin, a first seat disc, and a seat screw. The first seat disc is disposed between the pin and the diaphragm. The first seat disc and the pin define a first void. The first spring biases the diaphragm toward the first seat disc. The seat screw is engaged with the body and slidably engaged with the pin. The seat screw and the pin define a fluid passage in fluid communication with the first void. The second port is in fluid communication with the fluid passage and third port is in fluid communication with an undersurface of the diaphragm. 
     In a further embodiment, a valve for conveying fluid comprises a bonnet, a body, a flexible diaphragm, a first spring, and a spindle unit. The bonnet is secured to the body. The body defines a first port, a second port, and a third port. The flexible diaphragm is compressed between the bonnet and the body. The first spring is disposed in the bonnet. The spindle unit is disposed in the body and comprises a pin, a first seat disc, a seat screw, a seat, and a second seat disc. The first seat disc is disposed between the pin and the diaphragm. The first seat disc and the pin define a first void. The first spring biases the diaphragm toward the first seat disc. The seat screw threadably engages the body and slidably engages the pin. The seat screw and the pin define a fluid passage in fluid communication with the first void. The seat is retained in the body by the seat screw and slidably engages the pin. The second seat disc is secured to the pin and sealingly engages the seat. The valve is configured to have (a) a first position where the first port and the second port are in internal fluid communication and neither the first port nor the second port are in internal fluid communication with the third port, (b) a second position where the second port and the third port are in internal fluid communication and neither the second port nor the third port are in internal fluid communication with the first port, and (c) a third position where none of the first port, the second port, and the third port are in internal fluid communication. In the first position, the second seat disc is disengaged from the seat and the first seat disc is sealingly engaged with the pin. In the second position, the second seat disc is sealingly engaged with the seat and the first seat disc is disengaged from the pin. In the third position, the second seat disc is sealingly engaged with the seat and the first seat disc is sealingly engaged with the pin. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a valve. 
         FIG. 2  is a front view of the valve. 
         FIG. 3  is a cross-sectional view of the valve along section line A-A of  FIG. 1 . 
         FIG. 4  is a cross-sectional view of the valve along section line B-B of  FIG. 2 . 
         FIG. 5  is a cross-sectional view of a spindle unit of the valve. 
         FIG. 6  is a cross-sectional view of a body of the valve along section line A-A of  FIG. 1 . 
         FIG. 7  is a cross-sectional view of the body along section line B-B of  FIG. 2 . 
         FIG. 8  is lower isometric view of the body. 
         FIG. 9  is a partial enlargement of the cross-sectional view of the body of  FIG. 7 . 
         FIG. 10  is a partial enlargement of the cross-sectional view of the body of  FIG. 7 . 
         FIG. 11  is a cross-sectional view of a pin of the spindle unit. 
         FIG. 12  is a top view of a first seat disc of the spindle unit. 
         FIG. 13  is a cross-sectional view of the first seat disc along section line C-C of  FIG. 12 . 
         FIG. 13A  is a cross-sectional view of an alternative first seat disc. 
         FIG. 14  is a top view of a guide of the spindle unit. 
         FIG. 15  is a cross-sectional view of the guide along section line D-D of  FIG. 14 . 
         FIG. 16  is a top view of a seat screw of the spindle unit. 
         FIG. 17  is a cross-sectional view of the seat screw along section line E-E of  FIG. 15 . 
         FIG. 18  is a top view of a seat of the spindle unit. 
         FIG. 19  is a cross-sectional view of the seat along section line F-F of  FIG. 18 . 
         FIG. 20  is a partial enlargement of the cross-sectional view of the seat of  FIG. 19 . 
         FIG. 21 . is a top view of a washer of the spindle unit. 
         FIG. 22 . is a cross-sectional view of the washer along section line G-G of  FIG. 21 . 
         FIG. 23  is a top view of a second seat disc of the spindle unit. 
         FIG. 24  is a cross-sectional view of the second seat disc along section line H-H of  FIG. 23 . 
         FIG. 25  is a cross-sectional view of a bonnet of the valve. 
         FIG. 26  is a top view of a bonnet screw of the valve. 
         FIG. 27  is a cross-sectional view of the bonnet screw along section line J-J of  FIG. 26 . 
         FIG. 28  top view of a diaphragm of the valve prior to deformation. 
         FIG. 29  is a side view of the diaphragm prior to deformation. 
         FIG. 30  is a top view of an o-ring of the valve. 
         FIG. 31  is a cross-sectional view of the o-ring. 
         FIG. 32  is a cross sectional view of a spring support of the valve. 
         FIG. 33  is a cross sectional view of a diaphragm plate of the valve. 
         FIG. 34  is a side view of an alternative valve. 
         FIG. 35  is a front view of the alternative valve. 
         FIG. 36  is a cross-sectional view of the alternative valve along section line K-K of  FIG. 34 . 
         FIG. 37  is a cross-sectional view of the alternative valve along section line M-M of  FIG. 35 . 
         FIG. 38  is a cross-sectional view of a body of the alternative valve along section line K-K of  FIG. 34 . 
         FIG. 39  is a cross-sectional view of the body of the alternative valve along section line M-M of  FIG. 35 . 
         FIG. 40  is a schematic diagram of a cryogenic system integrating the valve. 
     
    
    
     DETAILED DESCRIPTION 
     The description that follows describes, illustrates and exemplifies one or more embodiments of the present invention in accordance with its principles. This description is not provided to limit the invention to the embodiments described herein, but rather to explain and teach the principles of the invention in order to enable one of ordinary skill in the art to understand these principles and, with that understanding, be able to apply them to practice not only the embodiments described herein, but also other embodiments that may come to mind in accordance with these principles. 
     The scope of the present invention is intended to cover all such embodiments that may fall within the scope of the appended claims, either literally or under the doctrine of equivalents. The specification describes exemplary embodiments which are not intended to limit the claims or the claimed inventions. Features described in the specification, but not recited in the claims, are not intended to limit the claims. 
     It should be noted that in the description and drawings, like or substantially similar elements may be labeled with the same reference numerals. However, sometimes these elements may be labeled with differing numbers, such as, for example, in cases where such labeling facilitates a more clear description. Additionally, the drawings set forth herein are not necessarily drawn to scale, and in some instances proportions may have been exaggerated to more clearly depict certain features. Such labeling and drawing practices do not necessarily implicate an underlying substantive purpose. Further, each of the drawings may be drawn to a different scale (e.g., the scale of  FIG. 1  may be different than the scale of  FIG. 28 ). 
     Some features may be described using relative terms such as top, bottom, vertical, rightward, leftward, etc. It should be appreciated that such relative terms are only for reference with respect to the appended drawings. These relative terms are not meant to limit the disclosed embodiments. More specifically, it is contemplated that the valves depicted in the appended drawings will be oriented in various directions in practice and that the relative orientation of features will change accordingly. 
     As stated above, the present specification is intended to be taken as a whole and interpreted in accordance with the principles of the present invention as taught herein and understood by one of ordinary skill in the art. 
       FIGS. 1 to 33  illustrate exemplary structural features of a combination regulator valve  1 . With reference to  FIGS. 1-4 , valve  1  has a longitudinal axis L and includes a setting portion  2  joined with a flowing portion  12 . The combination regulator valve  1  serves as a fluid economizer and as a fluid regulator When serving as a fluid economizer, valve  1  accepts fluid at a second port  13   b  and expels the fluid through a third port  13   c . When serving as a fluid regulator, valve  1  accepts fluid at a first port  13   a  and expels the fluid through the second port  13   b.    
     Setting portion  2  enables user adjustment of the one or more pressures that cause valve  1  to perform the regulator function and the economizer function. More specifically, setting portion  2  enables user adjustment via compression of a first spring  8 . The compression of the first spring  8  controls an amount of fluid pressure necessary in flowing portion  12  to (a) cause a diaphragm  28  to upwardly flex, (b) cause the diaphragm  28  to downwardly flex, and (c) enable the diaphragm  28  to occupy a neutral or flat position. 
     Setting portion  2  includes an adjustable screw  3 , a nut  4 , a ball  5 , a spring support  6 , a bonnet  7 , a first spring  8 , a bonnet screw  9 , and a diaphragm plate  10 . Screw  3  is threaded into the nut  4  and the bonnet  7 . One end of the screw  3  bears on the ball  5 , which is seated in the spring support  6 . The spring support  6  and the diaphragm plate  10  compress the first spring  8  therebetween. 
     A user may adjust the compression of the first spring  8  by rotating the screw  3  with respect to the nut  4  and the bonnet  7 . When the screw  3  is rotated in a first direction (e.g., clockwise), the screw  3  moves downward, thus pushing the ball  5  downward. Because the ball  5  is seated between the screw  3  and the spring support  6 , downward motion of the ball  5  and the screw  3  force the spring support  6  downward. The diaphragm plate  10  is seated on the diaphragm  28 , which generally opposes downward motion. Consequently, compression of the first spring  8  increases from the smaller distance between the spring support  6  and the diaphragm plate  10 . When compression of the first spring  8  increases, the first spring  8  exerts more downward force against the diaphragm plate  10 . 
     When the screw  3  is rotated in a second, opposite direction (e.g., counter-clockwise), the screw  3  moves upwards. The first spring  8  presses the spring support  6  upward until the ball  5  contacts the screw  3 . Compression of the first spring  8  decreases due to the increased distance between the spring support  6  and the diaphragm plate  10 . When compression of the first spring  8  decreases, the first spring  8  exerts less downward force against the diaphragm plate  10 . 
     The flowing portion  12  is configured to (a) enable internal fluid communication between the first port  13   a  and the second port  13   b , (b) enable internal fluid communication between the second port  13   b  and the third port  13   c , and (c) disable internal fluid communication between the first, second and third ports  13   a ,  13   b ,  13   c . With reference to  FIGS. 1-5 , flowing portion  12  includes a body  13 , an o-ring  14 , a spindle unit  15 , and the diaphragm  28 . As shown in  FIGS. 3-5 , the spindle unit  15  includes a first seat disc  17  (also called a pin engager or a sealing surface engager), a guide  18 , a pin  20  (also called an extender), a seat screw  21 , a seat  22 , a washer  23 , a second seat disc  26  (also called a seat engager or a sealing surface engager), and a second spring  27 . 
     With reference to  FIGS. 3-5 , the bonnet screw  9  compresses the bonnet  7  against first and second outer portions of the diaphragm  28 . The first outer portion of the diaphragm  28  is compressed between the o-ring  14  and the bonnet  7 . The second outer portion is radially outward of the first outer portion and is compressed between the body  13  and the bonnet  7 . Thus, the diaphragm  28  discourages fluid leakage from void  13   k  and past the bonnet  7  at the first outer portion and at the second outer portion. 
     The guide  18  is threaded into the body  13  and slidably captures the seat disc  17 . The guide  18  inwardly bears on the seat disc  17  to longitudinally align the seat disc  17  along the longitudinal axis L. The seat screw  21  inwardly bears on the pin  20  to longitudinally align the pin  20  along the longitudinal axis L. The seat screw  21  is not sealingly engaged with the pin  20 . Void  17   c  is in fluid communication with void  22   c  via the seat screw  21  as will be explained in greater detail in conjunction with  FIGS. 16-17 . The pin  20  includes a valve seat  204  for sealingly engaging first seat disc  17 . Further, the seat screw  21  is threaded into the body and axially bears on the seat  23  to capture the seat  23  in the body  13 . The washer  23  is compressed between the seat  22  and the body  13  to discourage fluid from flowing between the body  13  and the seat  22 . 
     The seat  22  sealingly engages the second seat disc  26  at valve seat  224 . The pin  20  is inserted into the second seat disc  26  to longitudinally align the second seat disc  26  with the longitudinal axis L. The second seat disc  26  receives the second spring  27  to capture the second spring  27  between the second seat disc  26  and the body  13  and to longitudinally align the second spring  27  with the longitudinal axis L. An inner surface of the second seat disc  26  bears on the second spring  27 . 
     As stated above, the first spring  8  biases the diaphragm  28  downward. Fluid pressure in void  13   k  biases the diaphragm  28  upward. Additionally, with reference to  FIGS. 3-5 , fluid pressure in voids  17   c  and  18   c , bears on the first seat disc  17  to bias diaphragm  28  upward. The second spring  27  biases diaphragm  28  upward, but only until the second seat disc  26  engages the seat  22 . Similarly, fluid pressure in void  13   e  biases diaphragm  28  upward, but only until the second seat disc  26  engages the seat  22 . It should be understood that the diaphragm  28  may be naturally biased toward the upwardly flexed position, a neutral (i.e., flat) position, or the downwardly flexed position as a result of internal stresses induced during manufacturing. 
     The above-described biases and fluid pressure apply force to the diaphragm  28  and thus determine whether the diaphragm  28  is upwardly flexed, downwardly flexed, or neutral. It should be appreciated that because void  13   k  has a greater area parallel to diaphragm  28  than voids  17   c , pressure in void  13   k  influences the position of diaphragm  28  to a greater extent than pressure in void  17   c.    
     Upon installation, a user cannot access the third spring  27  or the diaphragm  28  without removing the bonnet  7 . Thus, by rotating the screw  3 , the user may control the fluid pressure in voids  13   k  and  17   c  that causes diaphragm  28  to upwardly flex and the fluid pressure in voids  13   k  and  17   c  that enables the diaphragm  28  to downwardly flex. More specifically, when the user moves the screw  3  downward, a greater minimum amount of pressure in voids  13   k  and/or  17   c  is needed to cause the diaphragm  28  to upwardly flex and a lesser maximum amount of pressure in voids  13   k  and/or  17   c  enables the diaphragm  28  to downwardly flex. In contrast, when the user moves the screw  3  upward, a lesser minimum amount of pressure in voids  13   k  and/or  17   c  is needed to cause the diaphragm  28  to upwardly flex and a greater maximum amount of pressure in voids  13   k  and/or  17   c  enables the diaphragm  28  to downwardly flex. 
     Upon flexing downward past the neutral or flat position, the diaphragm  28  presses the seat disc  17  downward until the seat disc  17  sealingly engages the pin  20 . The spindle unit  15 , more specifically the second spring,  27 , is configured such that when the diaphragm  28  flexes downward, the first seat disc  17  sealingly engages the pin  20  before the second seat disc  26  overcomes the upward bias of the second spring  27  to release from seat  22 . By virtue of contact between the first seat disc  17  and the pin  20 , the pin  20  overcomes the upward bias of the second spring  27  and moves downward with the seat disc  17 . 
     With reference to  FIGS. 3-5 , when the diaphragm  28  downwardly flexes, the second seat disc  26 , which is engaged with the pin  20 , moves downward and away (i.e., disengages) from the seat  22 , which is static with respect to the body  13 . Upon disengagement between the seat disc  26  and the seat  22 , fluid communication between the first port  13   a  and the second port  13   b  occurs via voids  13   d ,  13   e ,  22   c ,  22   b , and  13   f . Because seat disc  17  sealingly engages pin  20 , internal fluid communication is blocked between (a) the first and second ports  13   a ,  13   b  and (b) the third port  13   c  through flowing portion  12 . Put differently, internal fluid communication only occurs between the first and second ports  13   a  and  13   b.    
     As diaphragm  28  flexes downward, compression of at least the second spring  27  increases, thus increasing the upward force exerted by the second spring  27  against the second seat disc  26  and the pin  20 . Eventually, the upward force exerted by the second spring  27  will overcome the downward force applied by the first spring  8  against the diaphragm  28 , thus arresting further downward movement of the pin  20 . 
     When fluid pressure in void  13   k  flexes the diaphragm  28  upward past the neutral or flat position, the second spring  27  pushes second seat disc  26  against seat  22  such that second seat disc  26  occupies the closed position shown in  FIGS. 3-4 . Because the second seat disc  26  stops against seat screw  22 , pin  20  cannot move upward with first seat disc  17 . Further, fluid pressure in voids  22   c ,  18   c , and  17   c  urges the first seat disc  17  away from the pin  20 . 
     With reference to  FIGS. 3-5 , fluid pressure in void  13   k  spread across the surface area of diaphragm  28  produces a first force. Fluid pressure in void  13   k  spread across the surface area of the topside of the first seat disc  17  produces a second force. Fluid pressure in void  17   c  spread across the surface area of the underside of the first seat disc  17  radially outside of the valve seat  204  produces a third force. When the first force overcomes the downward force of the first spring  8 , the diaphragm  28  flexes upwardly. When the third force overcomes the second force, the first seat disc  17  slides in the guide  18  and disengages from the pin  20 . In other words, a first minimum fluid pressure in void  13   k  spread across the surface area of the diaphragm  28  overcomes the downward force of the first spring  8  and a second minimum pressure in void  17   c  spread across the bottom surface area of the first seat disc  17  outside of the valve seat  204  overcomes the downward force of fluid pressure in void  13   k  spread across the top surface area of the first seat disc  17 . Thus, fluid communication is enabled between the second port  13   b  and the third port  13   c  via voids  13   f ,  22   b ,  22   c ,  18   c ,  17   c ,  13   k , and  13   q.    
     By virtue of the engagement between the second seat disc  26  and the seat  22 , internal fluid communication is blocked between (a) the first port  13   a  and (b) the second and third ports  13   b ,  13   c . Put differently, internal fluid communication only occurs between the second and third ports  13   b ,  13   c . The spindle unit  15  is configured such that when the diaphragm  28  flexes upward, the second seat disc  26  sealingly engages the seat  22  before the first seat disc  17  disengages from pin  20 . 
     A shoulder  71  of the bonnet  70  serves as a stop for the diaphragm plate  10 . The combination of the shoulder  71  and the diaphragm plate  10  thus prevent the diaphragm  28  from upwardly flexing past a certain degree, irrespective of fluid pressure. 
     When the diaphragm  28  is in the neutral or flat position, as shown in  FIGS. 3-4 , the diaphragm  28  counters the upward force of fluid pressure in void  17   c  to keep the first seat disc  17  sealingly engaged with pin  20 . The second spring  27  overcomes downward bias of the diaphragm  28  against the pin  20  and causes the second seat disc  26  to sealingly engage the seat  22 . As a result, the valve  1  blocks internal fluid communication between all of ports  13   a ,  13   b ,  13   c.    
     The spindle unit  15  is sized and configured to for the valve seat  204  to sealingly bear against the bottom of the first seat disc  17  when the diaphragm  28  is in the neutral position. Additionally, the spindle unit  15  is configured for the second seat disc  26  to sealingly bear against the seat  22  when the diaphragm  28  is in the neutral position. 
     As shown in  FIGS. 6-10 , the body  13  defines (a) first, second, and third ports  13   a ,  13   b ,  13   c  and (b) voids  13   d ,  13   e ,  13   f ,  13   g ,  13   h ,  13   i ,  13   j ,  13   k ,  13   m ,  13   n ,  13   p , and  13   q . For the reader&#39;s convenience and to avoid confusion, the void numbering skips  131  and  13   o.    
     The first, second, and third ports  13   a ,  13   b ,  13   c  are partially conical and transversely extending in the body  13 . The first and second ports  13   a ,  13   b  are opposite one another with collinear central axes. The third port  13   c  has a central axis perpendicular to the central axes of the first and second ports  13   a ,  13   b.    
     Void  13   d  is cylindrical with a central axis angled with respect to the longitudinal axis L and the central axis of the first port  13   a . Void  13   e  is cylindrical and linked to void  13   a  via void  13   d . Void  13   e  has a central axis parallel to and collinear with the longitudinal axis L. Void  13   e  accommodates the second seat disc  26 , an end of the second spring  27 , at least a portion of the seat  22 , and at least a portion of the pin  20 . Void  13   f , has a central axis perpendicular to the longitudinal axis L, has three lobes, and links the second port  13   b  with void  22   b  of the seat  22 . 
     Void  13   g  is disc shaped and accommodates at least a portion of the seat  22 , at least a portion of the pin  20 , and the washer  23 . Void  13   g  may be sized and configured to enable fluid in void  22   b  of the seat  22  to communicate with void  13   f  without passing through void  13   g . A central axis of void  13   g  is collinear with the longitudinal axis L. Void  13   g  has a maximum diameter exceeding the maximum diameters of voids  13   e  and  13   h . As shown in  FIG. 10 , void  13   g  includes ring-shaped void  130   g . When viewed in cross section, void  130   g  is triangular. The washer  23  sits directly above void  130   g.    
     Void  13   h  is cylindrical. Inner surfaces of the body  13  defining void  13   h  are threaded to threadably engage with the seat screw  21 . A central axis of void  13   h  is parallel to the longitudinal axis L. Void  13   h  accommodates the threaded portion of the seat screw  21  and at least a portion of the pin  20 . Void  13   i  is a conical transition between voids  13   h  and  13   j . Void  13   i  has a larger major diameter than the non-threaded portion of void  13   h  and a central axis collinear with longitudinal axis L. 
     Void  13   j  is cylindrical. Inner surfaces of the body  13  defining void  13   j  are threaded to threadably engage with the guide  18 . A central axis of void  13   j  is parallel to the longitudinal axis L. Void  13   j  accommodates at least portions of the guide  18 , the pin  20 , and the first seat disc  17 . Void  13   k  is cylindrical with a central axis collinear with the longitudinal axis L. Void  13   k  has a greater diameter than any of voids  13   e ,  13   g ,  13   h ,  13   i , and  13   j . Void  13   k  accommodates at least portions of the guide  18  and the first seat disc  17 . When downwardly flexed, the diaphragm  28  protrudes into void  13   k.    
     Void  13   m  is cylindrical with a central axis collinear with the longitudinal axis L. A portion of the inner surfaces of the body  13  defining void  13   m  are threaded to threadably engage with the bonnet screw  9 . A portion of the inner surfaces defining void  13   m  are not threaded to enable the bonnet  7  to outwardly bear against the body  13 . Void  13   m  accommodates the bonnet screw  9 , a portion of the bonnet  7 , at least a portion of the diaphragm plate  10 , a portion of the first spring  8 , and the diaphragm  28  when in the neutral or upwardly flexed positions. As shown in  FIG. 9 , void  13   m  includes a ringed portion  130   m  which extends into the body  13  at a non-perpendicular angle with respect to the longitudinal axis L. 
     Void  13   n  is ring-shaped with a central axis collinear with the longitudinal axis L. Void  13   n  accommodates the o-ring  14 . As shown in  FIG. 9 , the bottom of void  13   n  is uneven by virtue of an upwardly extending surface  132  configured to deform the o-ring  14 . Void  13   p  is ring-shaped, lies below void  13   k , and has a central axis collinear with the longitudinal axis L. Void  13   q  has a central axis offset from, but parallel with the longitudinal axis L and connects port  13   c  with void  13   k  via void  13   p.    
     With reference to  FIG. 11 , the pin  20  includes an upper portion  201  and a lower portion  202 . The upper portion  201  includes a protruding portion  201   a  and a main portion  201   b . The protruding portion  201   a  defines void  20   c . Void  20   c  is partially conical and has a central axis collinear with the longitudinal axis L and fluidly communicates with void  13   k  via the first seat disc  17 . The protruding portion  201   a  includes the valve seat  204  for sealingly engaging the first seat disc  17 . The lower portion  202  includes an extension portion  202   a , a guiding portion  202   b , and an engaging portion  202   c . The guiding portion  202   b  engages a top surface of the second seat disc  26  to longitudinally stabilize the second seat disc  26 . The engaging portion  202   c  extends into the second seat disc  26 . 
     As shown in  FIGS. 12-13 , the first seat disc  17  defines voids  17   a ,  17   b ,  17   c ,  17   d , and  17   e . Voids  17   a  and  17   c  are cylindrical and void  17   c  has a greater diameter than void  17   a . Void  17   b  is channel-shaped and perpendicular to the longitudinal axis L. Void  17   c  is in fluid communication with void  13   k  of the body  13  via voids  17   a  and  17   b . Void  17   d  is ring-shaped and extends from void  17   c . Void  17   e  is conical. Voids  17   a ,  17   b ,  17   c ,  17   d , and  17   e  respectively have central axes collinear with the longitudinal axis L. 
     The first seat disc  17  includes first and second upper surfaces  171  and  172 . The first upper surface  171  is circular and elevated above the second upper surface  172 . The first upper surface  171  bears against the diaphragm  28 . The second upper surface  172  defines a bottom of the channel-shaped void  17   b  disposed below the first upper surface  171  such that at least when the diaphragm  28  is in the neutral or flat position, the first upper surface  171 , but not the second upper surface  172 , bears on the diaphragm  28 . The first seat disc  17  includes an inner surface  173 , configured to compressively seal against pin  20 . As shown in  FIGS. 12-13 , the first seat disc  17  includes an outer perimeter  174  transitionally connected to the first upper surface  171  via rounded edges  175 . As shown in  FIG. 13 , the outer perimeter  174  includes one or more outwardly extending sealing rings  176  to sealingly engage with the guide  18 . 
       FIG. 13A  illustrates an alternative first seat disc  1700  that may be substituted into the spindle  15  of  FIG. 5  in place of the first seat disc  17 . As shown in  FIG. 13A , the alternative first seat disc  1700  defines voids  1700   a ,  1700   b ,  1700   c ,  1700   d , and  1700   e . Voids  1700   a  and  1700   c  are cylindrical and void  1700   c  has a greater diameter than void  1700   a . Void  1700   b  is channel-shaped and perpendicular to the longitudinal axis L when the alternative first seat disc  1700  is installed in the spindle  15 . Void  1700   c  is in fluid communication with void  13   k  of the body  13  via voids  1700   a  and  1700   b  when the alternative first seat disc  1700  is installed in the spindle  15 . Void  1700   d  is toroidal and extends from void  1700   c . Void  1700   e  is conical. Voids  1700   a ,  1700   b ,  1700   c ,  1700   d , and  1700   e  respectively have central axes collinear with the longitudinal axis L. 
     The alternative first seat disc  1700  includes first and second upper surfaces  1701  and  1702 . The first upper surface  1701  is circular and elevated above the second upper surface  1702 . The first upper surface  1701  bears against the diaphragm  28 . The second upper surface  1702  defines a bottom of the channel-shaped void  1700   b  disposed below the first upper surface  1701  such that at least when the diaphragm  28  is in the neutral or flat position, the first upper surface  1701 , but not the second upper surface  1702 , bears on the diaphragm  28 . The alternative first seat disc  1700  includes an inner surface  1703 , configured to compressively seal against pin  20 . As shown in  FIG. 13A , the first seat disc  1700  includes an outer perimeter  1704  transitionally connected to the first upper surface  1701  via rounded edges  1705 . As shown in  FIG. 13A , the outer perimeter  1704  includes an outwardly extending sealing ring  1706  to sealingly engage with the guide  18 . The alternative first seat disc  1700  includes a support ring  1707  disposed in void  1700   d . The support ring  1707  provides outward support (e.g., radial stiffening) as the alternative first seat disc  1700  sealingly engages with the guide  18  via the sealing ring  1706 . In some examples, the support ring  1707  is metallic (e.g., steel, stainless steel, brass, bronze, aluminum, etc.). 
     As shown in  FIGS. 14-15 , the guide  18  includes an upper surface  181 , outer threads  182 , an inner lip  183 , a bottom surface  184 , an unthreaded outer perimeter  185 , a rounded edge  186 , and an inner surface  187 . The guide  18  threadably engages with the body  13  via the outer threads  182 . The guide  18  defines voids  18   a ,  18   b ,  18   c , and  18   d . A tool may be inserted into voids  18   b  to tighten threaded engagement between the guide  18  and the body  13 . Void  18   a  has cylindrical and conical portions, has a central axis collinear with the longitudinal axis L, and is defined by the inner lip  183 . Void  18   c  is cylindrical with a diameter greater than the cylindrical portion of void  18   a , has a central axis collinear with the longitudinal axis L. Void  18   c  is transitionally connected to the cylindrical portion of void  18   a  via the conical portion of void  18   a . Void  18   d  is conical and transitionally connects the inner surface  187  to the bottom surface  184 . The unthreaded outer perimeter  185  is transitionally connected to the bottom surface  184  via the rounded edge  186 . The inner lip  183  has a diameter less than the inner surface  187 . The inner lip  183  bears against the outer perimeter  174  of the first seat disc  17  and captures the first seat disc  17  via the sealing rings  176 . 
     As shown in  FIGS. 16-17 , the seat screw  18  includes an upper surface  211 , outer threads  212 , a bottom surface  213 , at least one chamfer  214 , and an inner surface  215 . Voids  21   a  and  21   b  are defined by the inner surface  215 . Void  21   a  is cylindrical and has a central axis collinear with the longitudinal axis L. Each void  21   b  forms a corner in communication with void  21   a . In other words, the voids  21   b  are extensions (e.g., offshoots) of cylindrical void  21   a . The seat screw  21  is threadably engaged with the body  13  via the outer threads  212 . Void  21   a  accommodates the pin  20  to slidably engage the pin  20  with the inner surface  215  and each void  21   b  forms a fluid passage between the seat screw  21  and the pin  20 . In operation, fluid communicates between voids  22   c  and  18   c  (shown in  FIGS. 3-4 ) via voids  21   b . A tool may be inserted into voids  21   b  to tighten threaded engagement between the seat screw  21  and the body  13 . In other words, the voids  21   b  serve to convey fluid when the pin  20  is inserted into void  21   a  and to provide at least one tool engagement surface. In the illustrated example of  FIG. 16 , the voids  21   b  are arranged hexagonally. It should be understood that the seat screw  21  may define any number of voids  21   b  greater than zero and that the voids  21   b  may be any shape (e.g., rectangular, lobed, etc.). Chamfer  214  provides a lead-in to facilitate insertion of the pin  20  into the seat screw  21  and sliding engagement of the pin  20  with the seat screw  21 . 
     With reference to  FIGS. 18-20 , the seat  22  defines voids  22   a ,  22   b ,  22   c , and  22   d . Voids  22   a  and  22   b  are cylindrical and have respective central axes collinear with the longitudinal axis L. Void  22   a  has a greater diameter than void  22   b . Void  22   d  is conical and transitionally connects voids  22   a  and  22   b . Voids  22   a  and  22   b  accommodate a portion of the pin  20 . Void  22   c  is channel-shaped, is substantially perpendicular with the longitudinal axis L, and links to void  13   f . The seat  22  includes a first upper surface  221 , a first shoulder  222  for engaging the washer  23 , a second shoulder  223 , and a second upper surface  225 . The second upper surface  225  is disposed below the first upper surface to define the channel-shaped void  22   c . The second shoulder  223  includes the ring-shaped valve seat  224  for bearing against the second seat disc  26 . The valve seat  224  narrows as it extends in the downward direction, such that the outer diameter of the valve seat  224  shrinks while the inner diameter of the valve seat  224  remains constant. 
     With reference to  FIGS. 21-22 , the washer  23  includes an upper surface  231 , a bottom surface  232 , and an outer perimeter  233 . The washer  23  defines void  23   a . Void  23   a  is cylindrical, has a central axis collinear with the longitudinal axis L, and accommodates a portion of the pin  20 . The upper surface  231  engages the first shoulder  222  of the seat  22 . The bottom surface  232  engages the body  13 . 
     With reference to  FIGS. 23-24 , the second seat disc  26  defines voids  26   a ,  26   b ,  26   c ,  26   d , and  26   e . Voids  26   a ,  26   b ,  26   c ,  26   d , and  26   e  respectively have central axes collinear with the longitudinal axis L. Void  26   d  is conical. Voids  26   a ,  26   b ,  26   c , and  26   e  are cylindrical. Void  26   a  has a smaller diameter than void  26   b . Void  26   b  receives the guiding portion  202   b  of the pin  20 . Void  26   a  receives the engaging portion  202   c  of the pin  20 . The second seat disc  26  includes a first upper surface  261  configured to compressively seal against the seat screw  22 , a shoulder  262  configured to receive and inwardly bear against the second spring  27 , and a first outer perimeter  265  including a flat surface  263  and a round portion  264 . The flat surface  263  provides clearance for the second seat disc  26  in void  13   e . The second seat disc  26  also includes a second outer perimeter  266 , a transitional surface  267 , and a bottom surface  268 . The round portion  264  has a diameter greater than the second outer perimeter  266 . The transitional surface  267  is conical to transition between the second outer perimeter  266  and the first outer perimeter  265 . A rounded edge  269  is formed between the round portion  264  and the bottom surface  268 . A square edge  2610  is formed between the flat surface  263  and the bottom surface  268 . 
     As shown in  FIG. 25 , the bonnet  7  defines voids  7   a ,  7   b , and  7   c . Voids  7   a ,  7   b , and  7   c  are cylindrical and have central axes collinear with longitudinal axis L. The diameter of void  7   a  is smaller than the diameter of void  7   b . The diameter of void  7   b  is smaller than the diameter of void  7   c . The bonnet  7  includes the first shoulder  71 , a second shoulder  74 , and a third shoulder  75 . The diaphragm  28  engages with the second shoulder  74 . The bonnet screw  9  engages with the third shoulder  75 . The bonnet  7  includes internal threads  72 , which define void  7   a , and a vent hole  73 . Void  7   c  accommodates the diaphragm plate  10 . Void  7   b  accommodates the first spring  8  and the spring support  6 . 
     With reference to  FIGS. 26 and 27 , the bonnet screw  9  is ring-shaped and defines an inner cylindrical void  9   a  with a central axis collinear with the longitudinal axis L. The bonnet screw  9  defines a plurality of rectangular slots  9   b . A tool may be inserted into the slots  9   b  to enable a user standing above the bonnet  7  to torque the bonnet screw  9 . Put differently, without slots  9   b , a user would be unable to torque the bonnet screw  9  because outer walls of the body  13  surround the bonnet screw  9 . The bonnet screw  9  includes outer threads  91  configured to engage inner threads of the body  13 . The outer threads  91  may be continuous about an outer perimeter of the bonnet screw  9  or may be absent during intervals corresponding to slots  9   b . The bonnet screw  9  further includes a bottom surface  92 . The bottom surface  92  engages with the third shoulder  75  of the bonnet  7 . 
       FIGS. 28-29  show the diaphragm  28  prior to deformation and installation into the valve  1 . Prior to deformation, the diaphragm  28  is a flat, circular, and continuous piece of metal. After deformation, and when the diaphragm  28  is in the neutral or flat position, as shown in  FIGS. 3-4 , a circular inner portion is elevated above a ring-shaped outer portion. The circular inner portion is configured to contact the first seat disc  17  and the diaphragm plate  10 . The ring-shaped outer portion is configured to contact the o-ring  14 . Upon deformation, the diaphragm  28  remains continuous and solid to substantially prevent fluid from leaking into the interface between the diaphragm plate  10  and the bonnet  7 . 
     With reference to  FIGS. 30-31 , the o-ring  14  includes an outer perimeter  141  and defines void  14   a . The o-ring  14  is substantially toroidal (e.g., doughnut-shaped). Void  14   a  has a central axis collinear with the longitudinal axis L. The o-ring  14  sealingly engages with the body  13  via void  13   n  and with the diaphragm  28 . 
     With reference to  FIG. 32 , the spring support  6  includes an upper surface  61 , a bottom surface  62 , a shoulder  63 , a chamfer  64 , and an outer perimeter  65  and defines voids  6   a  and  6   b . Voids  6   a  and  6   b  have central axes collinear with the longitudinal axis L. Void  6   a  is cylindrical and partially conical. Void  6   b  is conical. Voids  6   a  and  6   b  accommodate the ball  5 . The shoulder  63  transitions to the bottom surface via the chamfer  64 . The shoulder  63  engages with the first spring  8 . The shoulder  63  and the top surface  61  respectively transition to the outer perimeter  65  via rounded edges. The chamfer  64  may provide a lead-in to facilitate engaging the first spring  8  with the shoulder  63 . 
     As shown in  FIG. 33 , the diaphragm plate  10  includes a lower surface  101 , a first upper surface  102 , a second upper surface  103 , a first ring  104 , and a second ring  105  and defines inner voids  10   a  and  10   b . Inner void  10   a  is defined by the first ring  104 , is cylindrical, and has a central axis collinear with the longitudinal axis L. Inner void  10   b  is defined by the first ring  104  and the second ring  105 , has a central axis collinear with the longitudinal axis L, and is configured to receive the first spring  8 . By virtue of first spring  8 , the lower surface  101  engages with the diaphragm  28  substantially continuously (i.e., lower surface  101  contacts the diaphragm  28  in all of the neutral or flat, upwardly flexed, and downwardly flexed positions). The first lower surface  102  is disposed below to the second upper surface  103 . The first ring  104  has a smaller diameter than the second ring  105 . The spring  8  is thus captured between the first ring  104  and the second ring  105 . The first ring  104  is chamfered to facilitate insertion of the first spring  8  into void  10   b . The second upper surface  103  is configured to contact shoulder or step  71  of bonnet  7  to arrest upward flexing of diaphragm  28 . 
       FIGS. 34 to 39  illustrate exemplary structural features of an alternative combination regulator valve  11 . The alternative valve  11  is an alternative embodiment of the valve  1  of  FIGS. 1-4 . With reference to  FIGS. 36-37 , the alternative valve  11  has the longitudinal axis L and includes the setting portion  2  and its respective components of  FIGS. 1-4, 25-27, and 32-33  as described above joined with an alternative flowing portion  121 . The alternative valve  11  serves as a fluid economizer and as a fluid regulator. When serving as a fluid economizer, alternative valve  11  accepts fluid at a second port  131   b  and expels the fluid through a third port  131   c . When serving as a fluid regulator, alternative valve  11  accepts fluid at a first port  131   a  and expels the fluid through the second port  131   b.    
     The alternative flowing portion  121  is configured to (a) enable internal fluid communication between the first port  131   a  and the second port  131   b , (b) enable internal fluid communication between the second port  131   b  and the third port  131   c , and (c) disable internal fluid communication between the first, second and third ports  131   a ,  131   b ,  131   c . With reference to  FIGS. 34-37 , the alternative flowing portion  121  includes an alternative body  131 , the o-ring  14  of  FIGS. 3-4 and 30-31 , the spindle unit  15  and its respective components of  FIGS. 3-5 and 11-24 , and the diaphragm  28  of  FIGS. 3-4 and 28-29 . 
     With reference to  FIGS. 34-37 , the bonnet screw  9  compresses the bonnet  7  against the first and second outer portions of the diaphragm  28 . The first outer portion of the diaphragm  28  is compressed between the o-ring  14  and the bonnet  7 . The second outer portion is radially outward of the first outer portion and is compressed between the alternative body  131  and the bonnet  7 . Thus, the diaphragm  28  discourages fluid leakage from void  131   k  and past the bonnet  7  at the first outer portion and at the second outer portion. 
     The guide  18  is threaded into the alternative body  131 . The seat screw  21  is threaded into the alternative body  131  and axially bears on the seat  22  to capture the seat  22  in the alternative body  131 . The washer  23  is compressed between the seat  22  and the alternative body  131  to discourage fluid from flowing between the alternative body  131  and the seat  22 . The second seat disc  26  receives the second spring  27  to capture the second spring  27  between the second seat disc  26  and the alternative body  131  and to longitudinally align the second spring  27  with the longitudinal axis L. Further connections and interactions of the components of the spindle unit  15  are as described above. 
     As described above, the first spring  8  biases the diaphragm  28  downward. Fluid pressure in void  131   k  biases the diaphragm  28  upward. Additionally, fluid pressure in voids of the spindle unit  15  bias diaphragm  28  upward as described above. Similarly, fluid pressure in void  131   e  biases diaphragm  28  upward, but only until upward movement of the spindle unit  15  is stopped as described above. 
     These biases and fluid pressures apply force to the diaphragm  28  and thus determine whether the diaphragm  28  is upwardly flexed, downwardly flexed, or neutral. It should be appreciated that because void  131   k  has a greater area parallel to diaphragm  28  than the voids of the spindle unit  15 , pressure in void  131   k  influences the position of diaphragm  28  to a greater extent than pressure in the spindle unit  15 . 
     Upon installation, a user cannot access the spindle unit  15  or the diaphragm  28  without removing the bonnet  7 . Thus, by rotating the screw  3 , the user may control the fluid pressures in void  131   k  and in the spindle unit  15  that causes diaphragm  28  to flex upwardly and downwardly as described above with respect to voids  13   k  and  17   c.    
     When the diaphragm  28  downwardly flexes, the spindle unit  15  is displaced to permit fluid communication between the first port  131   a  and the second port  131   b  via voids  131   d ,  131   e , the spindle unit  15 , and void  131   f . When the spindle unit  15  is displaced downwardly, internal fluid communication is blocked between (a) the first and second ports  131   a ,  131   b  and (b) the third port  131   c  through the alternative flowing portion  121 . Put differently, internal fluid communication only occurs between the first and second ports  131   a  and  131   b.    
     When fluid pressure in void  131   k  flexes the diaphragm  28  upward past the neutral or flat position, the spindle unit  15  occupies the closed position shown in  FIGS. 36-37  similar to the closed position of  FIGS. 3-4 . 
     Fluid pressure in void  131   k  spread across the surface area of the diaphragm  28  produces a first force. Fluid pressure in void  131   k  spread across the surface area of the topside of the first seat disc of the spindle unit  15  produces a second force, as described above. Fluid pressure in the spindle unit  15  produces a third force, as described above. When the first force overcomes the downward force of the setting portion  2 , the diaphragm  28  flexes upwardly. When the third force overcomes the second force, the first seat disc disengages from the pin of the spindle unit  15  as described above. Similar to above, a first minimum fluid pressure in void  131   k  spread across the surface area of the diaphragm  28  overcomes the downward force of the setting portion  2  and a second minimum pressure in the spindle unit  15  spread across the a portion of the bottom surface area of the first seat disc overcomes the downward force of fluid pressure in void  131   k  spread across the top surface area of the spindle unit  15 . Thus, fluid communication is enabled between the second port  131   b  and the third port  131   c  via voids  131   f , and  131   q  and the spindle unit  15 . 
     Similar to above, when the diaphragm  28  flexes upwardly, internal fluid communication is blocked between (a) the first port  131   a  and (b) the second and third ports  131   b ,  131   c . Put differently, internal fluid communication only occurs between the second and third ports  131   b ,  131   c.    
     When the diaphragm  28  is in the neutral or flat position, as shown in  FIGS. 36-37 , the diaphragm  28  counters the upward force of fluid pressure in the spindle unit  15  and the spindle unit  15  occupies the closed position, as described above. As a result, the alternative valve  11  blocks internal fluid communication between all of the first, second, and third ports  131   a ,  131   b ,  131   c.    
     As shown in  FIGS. 38-39 , the alternative body  131  defines (a) first, second, and third ports  131   a ,  131   b ,  131   c  and (b) voids  131   d ,  131   e ,  131   f ,  131   g ,  131   h ,  131   i ,  131   j ,  131   k ,  131   m ,  131   n ,  131   p , and  131   q . For the reader&#39;s convenience and to avoid confusion, the void numbering skips  131   l  and  131   o.    
     The first, second, and third ports  131   a ,  131   b ,  131   c  are partially conical and transversely extending in the body  131 . The second and third ports  131   b ,  131   c  are opposite one another with collinear central axes. The first port  131   a  has a central axis perpendicular to the central axes of the second and third ports  131   b ,  131   c.    
     Void  131   d  is cylindrical with a central axis angled with respect to the longitudinal axis L and the central axis of the first port  131   a . Void  131   e  is cylindrical and linked to void  131   a  via void  131   d . Void  131   e  has a central axis parallel to and collinear with the longitudinal axis L. Void  131   e  accommodates the spindle unit  15  in the same manner as void  13   e , described above. Void  131   f , has a central axis perpendicular to the longitudinal axis L, has three lobes, and links the second port  131   b  with voids of the spindle unit  15  in the same manner as void  13   f , described above. 
     Void  131   g  is disc shaped and accommodates the spindle unit  15  in the same manner as void  13   g , described above. A central axis of void  131   g  is collinear with the longitudinal axis L. Void  131   g  has a maximum diameter exceeding the maximum diameters of voids  131   e  and  131   h.    
     Void  131   h  is cylindrical. Inner surfaces of the alternative body  131  defining void  131   h  are threaded to threadably engage with the spindle unit  15 . A central axis of void  131   h  is parallel to the longitudinal axis L. Void  131   h  accommodates the spindle unit  15  in the same manner as void  13   h , described above. Void  131   i  is a conical transition between voids  131   h  and  131   j . Void  131   i  has a larger major diameter than the non-threaded portion of void  131   h  and a central axis collinear with longitudinal axis L. 
     Void  131   j  is cylindrical. Inner surfaces of the alternative body  131  defining void  131   j  are threaded to threadably engage with the spindle unit  15 . A central axis of void  131   j  is parallel to the longitudinal axis L. Void  131   j  accommodates the spindle unit  15  in the same manner as void  13   j , described above. Void  131   k  is cylindrical with a central axis collinear with the longitudinal axis L. Void  131   k  has a greater diameter than any of voids  131   e ,  131   g ,  131   h ,  131   i , and  131   j . Void  131   k  accommodates the spindle unit  15  in the same manner as void  13   k , described above. When downwardly flexed, the diaphragm  28  protrudes into void  13   k.    
     Void  131   m  is cylindrical with a central axis collinear with the longitudinal axis L. A portion of the inner surfaces of the alternative body  131  defining void  131   m  are threaded to threadably engage with the bonnet screw  9 . A portion of the inner surfaces defining void  131   m  are not threaded to enable the bonnet  7  to outwardly bear against the alternative body  131 . Void  131   m  accommodates the diaphragm  28  when in the neutral or upwardly flexed positions and the spindle unit  15  in the same manner as void  13   m , described above. 
     Void  131   n  is ring-shaped with a central axis collinear with the longitudinal axis L. Void  131   n  accommodates the o-ring  14 . Void  131   p  is ring-shaped, lies below void  131   k , and has a central axis collinear with the longitudinal axis L. Void  131   q  has a central axis offset from, but parallel with the longitudinal axis L and connects the third port  13   c  with void  131   k  via void  131   p.    
     Several advantages are offered by the valve and the alternative valve. First, the valve  1  and the alternative valve  11  separate the regulator function from the economizer function by applying two different independently moveable seat discs  17 ,  26 . The inclusion of independently moveable seat discs reduces the chances of unintended fluid communication between all three ports  13   a ,  13   b ,  13   c  in the valve  1  or between all three ports  131   a ,  131   b ,  131   c  when only fluid communication between two of the ports is desired. 
     Second, bonnet  7  and body  13  confine spindle unit  15  within valve  1  and within the alternative valve  11 . This confinement reduces the possibility of external leakage through the valve  1  or through the alternative valve  11  and reduces the chances of damage to spindle unit  15 . 
     Third, by applying the bonnet screw  9  to lock the bonnet  7  with respect to the body  13  or to the alternative body  131 , the chances of damage to the diaphragm  28  are reduced. Put differently, the bonnet screw  9  enables a user to stably and reliably compress diaphragm  28  between the bonnet  7  and the body  13  or the alternative body  131 . In at least some prior art designs, a bonnet is directly threaded to a body, which increases the chances of damaging a diaphragm, compressed between the bonnet and the body, during assembly. This is because the absence of a bonnet screw prevents a user from reliably controlling the compression between the body and the bonnet. 
     Fourth, the valve  1  and the alternative valve  11  enable a user to replace internal components in a single direction. More specifically, after disengaging the bonnet screw  9  and removing the bonnet  7 , a user can access and remove all of the spindle unit  15  when looking down at the body  13  or the body  131 . 
     Fifth, the valve  1  and the alternative valve  131  generate a metal-to-metal seal between diaphragm  28  and the body  13  or the alternative body  131 , respectively, along the outer circumference of the diaphragm  28 . The bonnet  7  compresses the diaphragm  28  against the body  13  or the alternative body  131  to ensure the integrity of the seal. Besides generating a tight seal, this compression ensures that the diaphragm  28  does not move horizontally or laterally (i.e., perpendicular to longitudinal axis L) during operation. 
     Sixth, the o-ring  14  provides an additional seal that discourages fluid from leaking past the diaphragm  28  and between the bonnet  7  and the body  13  or the alternative body  131 . Additionally, the o-ring  14 , by acting as a spring, absorbs some downward force applied to the diaphragm  28 . As a result, the o-ring  14  reduces the chances that downward force generated by the bonnet screw  9  and applied by the bonnet  7  will crack the diaphragm  28 . Furthermore, the presence of the o-ring  14  enables the diaphragm  28  to flex to a greater extent than at least some prior art diaphragms. More specifically, because the o-ring  14  acts as a spring to absorb forces applied against the diaphragm  28 , the diaphragm  28  can tolerate the greater forces associated with more extreme flexing positions. 
     Seventh, because the seat screw  22  is separate from body  13  and from the alternative body  131 , a user can machine the sealing surface (valve seat  224 ) against which second seat disc  26  seals prior to assembly. In at least some prior art designs, valve seats are formed on inner surfaces of a body. As a result, it is difficult to access and thus accurately machine these prior art valve seats. When those inner surfaces are downwardly facing, a bottom portion of the body may be threadably detachable from a top portion of the body to enable tool access to the downwardly facing inner surfaces. Because the seat screw  22  is removable, the body  13  and the alternative body  131  can be integrally formed. Additionally, a user may periodically replace the seat screw  22  without replacing the body  13  or the alternative body  131 . When valve seats are formed on inner surfaces of a body, these valve seats cannot be replaced without replacing the entire body. 
     Eighth, the first seat disc  17  is confined between the diaphragm  28  and the pin  20 . As a result, the first seat disc  17  does not need to be attached to the diaphragm  28 . In at least some prior art designs, a seat disc is attached to a diaphragm, necessitating a hole in the diaphragm for receiving the seat disc. Consequently, the present disclosure enables the diaphragm  28  to be a solid piece of material, which reduces the chances of leakage through the diaphragm  28 . 
     Ninth, the first seat disc  17  is an upside-down bowl design (i.e., bowl-shaped), which discourages contaminants from resting between the pin  20  and the inner surface  173  of the first seat disc  17 . Furthermore, the top of the first seat disc  17  includes an upper surface  171  and a lower surface  172 . Contaminants resting between the diaphragm  28  and the first seat disc  17  will thus be biased from the upper surface  171  toward the lower surface  172  due to the contact between the upper surface  171  and the diaphragm  28 . 
     This list of advantages is not exhaustive. Additional advantages of the invention are apparent with reference to other sections of the specification and the figures. 
     The o-rings  14  and the washer  23  may be a compressible polymer such as PTFE or Omni-seal. The diaphragm  28 , the body  13 , and the alternative body  131  may be metals. The first and second seat discs  17 ,  26  may be a compressible material such as PTFE to discourage the first seat disc  17  from damaging the diaphragm  28  and to discourage the second seat disc  26  from damaging the seat  22 . The remaining components of the valve  1  and the alternative valve  11  may be metal. 
       FIG. 40  schematically illustrates a cryogenic system  300  for receiving, storing, and dispensing cryogenic fluid (e.g., natural gas, oxygen, etc.). Cryogenic system  300  includes the valve  1 , a tank  301  (which includes an inner tank  303  and an outer tank  302 ), liquid phase fluid  304 , gas phase fluid  305 , a first two-way valve  306 , a second two-way valve  308 , a four-way junction or valve  307 , a two-way vent valve  309 , an inner tank rupture disk  310 , a pressure gauge  311 , a safety relief valve  312 , an outer tank rupture disc  313 , lines  320  to  330 , and a three-way junction  331 . It should be understood that, in another embodiment, the alternative valve  11  may also be used in the cryogenic system  300  in place of the valve  1 . 
     The tank  301  includes a protective outer tank  302  and an inner tank  303  for storing the fluid. Fluid inside the inner tank  303  naturally separates into liquid fluid  304  and a gas fluid  305 . Lines  328  and  330  fluidly communicate at the three-way junction  331 . Although lines  330  and  329  cross, lines  330  and  329  are distinct and not in fluid communication, as indicated by the jumpover in  FIG. 40 . Line  320  extends to a lower portion of the tank  301  to communicate with liquid fluid  304 . Line  328  extends to an upper portion of the tank  301  to communicate with gas fluid  305 . Line  327  is a pressure building coil and accepts liquid fluid  304  from a bottom of the tank  301 . Line  324  is a vaporizer. Line  327  connects to the first port  13   a . Line  328  connects to the second port  13   b . Line  329  connects to the third port  13   c . Junction or four-way valve  307  is configured to fluidly communicate lines  322 ,  323 ,  320 , and  329 . Junction or four-way valve  307  may enable a user to selectively isolate some or all of lines  322 ,  323 ,  320 , and  329  from junction or four-way valve  307 . 
     A user may fill the tank  301  by connecting a source of cryogenic fluid to line  321  and opening the first two-way valve  306 . A user may withdraw liquid fluid through line  321  after opening the first two-way valve  306 . A user may withdraw gas fluid through line  326  after opening the second two-way valve  308 . 
     As described above, the valve  1  is configured to (a) enable internal fluid communication between the first port  13   a  and the second port  13   b , (b) enable internal fluid communication between the second port  13   b  and the third port  13   c , and (c) disable internal fluid communication between the first, second, and third ports  13   a ,  13   b , and  13   c . As described above, the valve  1  is configured to perform these functions based on fluid pressure in voids  13   k ,  17   c , and  13   e . Fluid from the tank  301  enters void  13   k  via line  320 , the four-way valve  307 , line  329 , and the third port  13   c . Fluid from the tank  301  enters void  17   c  via line  328  and the second port  13   b . Fluid from the tank  301  enters void  13   e  via line  327  and the first port  13   a.    
     The valve  1  is configured to enable internal fluid communication between the first port  13   a  and the second port  13   b  when pressure of fluid in the tank  301  is below a first predetermined pressure. Due to the low pressure, and as previously discussed, the diaphragm  28  occupies the downwardly flexed position. As a result, the second seat disc  26  is disengaged from the seat  22 , and the first seat disc  17  is engaged with the pin  20 . Therefore, fluid communication through the valve  1  between the first port  13   a  and the second port  13   b  is enabled while fluid communication through the valve  1  between (a) the first and second ports  13   a  and  13   b  and (b) the third port  13   c  is disabled. When fluid communication between the first and second ports  13   a  and  13   b  is enabled, liquid fluid enters line  327  (the pressure building coil), which vaporizes the liquid fluid into a gas fluid. The gas fluid enters the first port  13   a , flows through the second port  13   b , and reenters the tank  301  as a gas. As a result, pressure in the tank  301  increases. 
     The valve  1  is configured to enable internal fluid communication between the second port  13   b  and the third port  13   c  when pressure in the tank  301  is above a second predetermined pressure. The second predetermined pressure is greater than the first predetermined pressure. Due to the higher pressure, as previously discussed, the diaphragm  28  occupies the upwardly flexed position. As a result, the second seat disc  26  is engaged with the seat  22 . When a user opens the first two-way valve  306  and/or the second two-way valve  308 , which are in fluid communication with the third port  13   c , fluid pressure in void  13   k  decreases suddenly while fluid pressure in void  17   c  substantially remains at the higher pressure. Thus, a pressure differential is formed between voids  13   k  and  17   c . Due to the pressure differential, the first seat disc  17  is disengaged from pin  20 . Therefore, fluid communication through the valve  1  between the second port  13   b  and the third port  13   c  is enabled while fluid communication through the valve  1  between (a) the second and third ports  13   b  and  13   c  and (b) the first port  13   a  is disabled. 
     When fluid communication between the second and third ports  13   b  and  13   c  is enabled and a user has opened two-way valve  308 , fluid flows from line  328 , through valve  1 , into line  329 , through the junction or four-way valve  307 , through line  323 , and into the vaporizer  324 . The vaporizer  324  converts any remaining liquid fluid into gas fluid and delivers the gas fluid to the two-way valve  308 . Fluid is dispensed to a consumer (e.g., an engine) via line  326 . 
     The valve  1  is configured to disable internal fluid communication between the first, second, and third ports  13   a ,  13   b , and  13   c  when fluid pressure in the tank  301  is between the first predetermined pressure and the second predetermined pressure. Upon opening the two-way valve  308 , fluid flows from line  320 , through the valve  307 , through line  323 , into the vaporizer  324  (where liquid fluid is converted to gas fluid), through the second two-way valve  308 , and out of line  326 . Upon opening the first two-way valve  306 , fluid flows through line  320 , through the four-way valve  307 , through line  322 , through the first two-way valve  306 , and out through line  321 . It should thus be appreciated that fluid delivered through the two-way valve  306  includes more liquid phase fluid than fluid delivered through the second two-way valve  308 .