Dome loaded back pressure regulator with center inlet and sanitary features

Abstract

A back pressure regulator includes: an orifice plate clamped between a reference cap and a body, the reference cap including a reference port; the orifice plate defining control and back surfaces and having a plurality of inlet orifices and outlet orifices passing therethrough; the body including: an inlet opening communicating with an exterior of the body, and at an inlet port communicating between the inlet opening and the inlet orifices; an outlet opening communicating with an exterior of the body, and an outlet port communicating between the outlet opening and the outlet orifices; and a diaphragm having opposed reference and process sides disposed between the orifice plate and the reference caps, the diaphragm movable between a first position engaged with the outlet orifices, and a second position wherein the diaphragm is not engaged with at least one of the outlet orifices.

Description

DOME LOADED BACK PRESSURE REGULATOR WITH CENTER INLET AND SANITARY FEATURESFIELD OF THE INVENTION

[0001] The present invention relates to pressure regulation in fluid systems, and more particularly to a pressure relief valve which balances vessel or line pressure against a reference pressure signal.BACKGROUND

[0002] A known type of back pressure regulator is a dome-loaded, direct diaphragm sealing type using multiple orifices. These back pressure regulators can adapt to a very wide range of flow requirements (well over 1000:1 flow coefficient ratio) in less than 1 second due to the native mechanical force balance of the diaphragm.

[0003] While effective, this type of regulator can have narrow passageways that can become plugged with debris or frozen product. This is undesirable in sanitary applications such as biopharmaceutical production or food and beverage applications, where all crevices must be exposed to the rinsing and cleaning processes.BRIEF SUMMARY OF THE INVENTION

[0004] These shortcomings of the prior art are addressed by a back pressure regulator with a center inlet and sanitary features.

[0005] According to one aspect of the technology described herein, a back pressure regulator includes: an orifice plate clamped between a reference cap and a body; the reference cap including a reference port; the orifice plate defining a control surface and an opposed back surface and having a plurality of inlet orifices passing therethrough and a plurality of outlet orifices passing therethrough; the body including: an inlet opening communicating with an exterior of the body, and at an inlet port communicating between the inlet opening and the inlet orifices; an outlet opening communicating with an exterior of the body, and an outlet port communicating between the outlet opening and the outlet orifices; and a diaphragmhaving opposed reference and process sides disposed between the orifice plate and the reference cap such that the process side contacts the control surface, the diaphragm movable between a first position engaged with the outlet orifices, and a second position wherein the diaphragm is not engaged with at least one of the outlet orifices.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:

[0001] FIG. 1 is a cross-sectional view of a back pressure regulator;

[0002] FIG. 2. is an enlarged view of a portion of FIG. 1 ;

[0003] FIG. 3 is a plan view of an orifice plate of the back pressure regulator of FIG. 1;

[0004] FIG. 4 is a plan view of a body of the back pressure regulator of FIG. 1 ; and

[0005] FIG. 5 is a section along lines 5 - 5 of FIG. 4.DETAILED DESCRIPTION OF THE INVENTION

[0007] Now, referring to the drawings wherein identical reference numerals denote the same elements throughout the various views, FIG. 1 illustrates an exemplary back pressure regulator 10 of a type referred to as a "dome-loaded, direct diaphragm sealing" type.

[0008] The pressure regulator 10 includes an orifice plate 12 disposed between a body 14 and a reference cap 16. Those components are clamped together by suitable means such as the illustrated bolts 18. The body 14 includes an inlet opening 20 and a outlet opening 22.

[0009] A diaphragm 24 made of flexible material such as PTFE sheeting (with or without fiber reinforcement), or PEEK, or polyimide, is disposed adjacent the orifice plate 12. The diaphragm 24 has opposed sides referred to as reference and processsides, with the process side facing the orifice plate 12. The perimeter of the diaphragm 24 is secured against the orifice plate 12 by the reference cap 16. Collectively, a space defined between the diaphragm 24 and the reference cap 16 is referred to as a "dome" 26 of the back pressure regulator 10.

[0010] A reference port 28 is formed in the reference cap 16 and is disposed in fluid communication with the reference side of the diaphragm 24.

[0011] The orifice plate 12 includes a control surface 30 that abuts the diaphragm 24, and an opposed back surface 32. A plurality of inlet orifices 34 pass through the orifice plate 12, as well as a plurality of outlet orifices 36.

[0012] The arrangement of orifices is shown in more detail in FIG. 3. The pressure regulator utilizes what will be referred to as a center-inlet orifice configuration, in which a cluster of the inlet orifices 34 are positioned in the center of the control surface 30, and the outlet orifices 36 are positioned surrounding the inlet orifices 34 (that is, outboard of the inlet orifices relative to a center line "C"). This provides a more uniform delivery of fluid across the control surface 30 and allows the diaphragm 24 to lift more easily, resulting in a more efficient regulator. In this instance, efficiency is defined as the ability of the regulator 10 to maintain a pressure set point over a wide range of flow rates. In tested examples, with a flow rate change of 500x, yielded a change in control pressure of 13%, however diaphragm selection can have a dramatic impact on efficiency. The tested diaphragm was chosen for long term robustness. More thin and supple diaphragms can approach 1500x change in flow with less than 5% change in control pressure, or even better.

[0013] The outlet orifice pattern is dispersed in such a way that it allows for a smooth radial opening / lifting of the diaphragm 24. In the illustrated example, the outlet orifices 36 are arrayed in a pattern that can be described by a series of concentric circles, examples being labeled BCD1, BCD2, BCD3, and BCD4. In tested examples, smooth radial opening was achieved with a minimum of four outlet orifice circle diameters, increasing in size by no more than 5 times the diameter of the outlet orifices 36.

[0014] The orifice plate 12 may include perimeter outlet orifices 37 at the perimeter of the control surface 30, such that when the pressure regulator 10 is installed in an "outlet down" vertical manner, one of the perimeter outlet orifices 37 will be positioned at the low point of the control surface 30. This will limit pooling of liquid, which is important when the end-user requires the back pressure regulator 10 have minimal holdup for cleaning / sanitary reasons.

[0015] Referring back to FIG. 1, the body 14 includes a top surface 38 which abuts the back surface 32 of the orifice plate 12 when the back pressure regulator 10 is assembled. The top surface 38 includes a shallow outlet cavity 40 formed therein. It is positioned to be in fluid communication with the outlet orifices 36. Referring to FIG. 4, the outlet cavity 40 may be an annular ring sized in such a way that average fluid velocity is not lost throughout the back pressure regulator 10. This is so that during clean in place ("CIP") operations, velocity stays high resulting in greater cleaning action throughout the back pressure regulator 10. In one example, the outlet cavity cross sectional area can be chosen such that its no more than 57% of the cross sectional area of the inlet opening 20 of the back pressure regulator 10. As seen in the lower portion of FIG. 1, the perimeter outlet orifice 37 described above may be aligned with an edge of the outlet cavity 40. This enhances drain ability of the device

[0016] The body 14 includes an inlet port 42 which extends from the inlet opening 20 to the top surface 38. In the illustrated example it turns, through a 90 degree angle. Alternatively, the inlet port 42 may extend straight through the bottom of the body 14 without making turns. Adjacent the top surface 38, The inlet port 42 may be angled or tapered (i.e. have a noncylindrical flow area) to encourage draining of the back pressure regulator 10 when oriented vertically with the outlet opening 22 facing downward. In one example, the included angle of the tapered portion of the inlet port 42 can be greater than or equal to 4 degrees. The inlet orifices 34 are disposed in fluid communication with the inlet port 42 and the control surface 30. The back pressure regulator 10 may utilize a sanitary fitting (e.g., TRICLAMP style) for process connection.

[0017] The body 14 includes an outlet port 44 which extends from the outletopening to the outlet cavity 40, turning through a 90 degree angle. The outlet orifices 36 are disposed in fluid communication with the outlet port 44 and the control surface 30.

[0018] The top surface 38 may incorporate one or more O-ring glands 46 for accepting resilient O-ring seals (O-rings not shown for clarity). In the illustrated example, three concentric O-ring glands 46 are shown. The O-ring gland 46 is exposed to the process fluid. Referring to FIG. 2, the O-ring gland 46 is configured with one recessed edge 48 such that when the back pressure regulator 10 is assembled, the polymer or elastomer O-ring will change shape and fill the O-ring gland 46 by a minimum of 102%, causing it to bulge slightly (a maximum of 0.025 inch intrusion) into the process stream, thus eliminating crevices which could potentially trap contamination. This is important to applications where sanitation is of importance.

[0019] The surface roughness of wetted surfaces in the back pressure regulator 10 may be less than or equal to 32Ra (microinches), with preferred roughnesses less than 20Ra for sanitary applications.

[0020] In use, reference port 28 of the back pressure regulator 10 is connected to a pressure reference source, the inlet opening 20 is connected to a process pressure, and the outlet port 44 is connected to a vent pressure. During normal balanced or modulating mode, the diaphragm 24 is drawn into a sealing relationship with the outlet orifices 36 due to the pressure differential between the vent pressure and reference pressure. When the process pressure exceeds the reference pressure the area of the diaphragm 24 between the outlet orifices 36 is persuaded away from the outlet orifices 36 thereby allowing venting through the outlet port 44.

[0021] In practice, the diaphragm 24 blocks the fluid flow to the outlet port 44 until the inlet pressure very slightly increases above the reference pressure. The diaphragm 24 then forms a quick acting mechanical "controller" to maintain a tight pressure balance.

[0022] The back pressure regulator 10 described above has advantages over theprior art. This design has been optimized for high performance use in sanitary applications such as biopharmaceutical production or food and beverage applications. Operational pressures can range from the millibar range to over lOObar.

[0023] The foregoing has described a back pressure regulator. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0024] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0025] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

WHAT IS CLAIMED IS:

1. A back pressure regulator, comprising: an orifice plate clamped between a reference cap and a body; the reference cap including a reference port; the orifice plate defining a control surface and an opposed back surface and having a plurality of inlet orifices passing therethrough and a plurality of outlet orifices passing therethrough; the body including: an inlet opening communicating with an exterior of the body, and at an inlet port communicating between the inlet opening and the inlet orifices; an outlet opening communicating with an exterior of the body, and an outlet port communicating between the outlet opening and the outlet orifices; and a diaphragm having opposed reference and process sides disposed between the orifice plate and the reference cap such that the process side contacts the control surface, the diaphragm movable between a first position engaged with the outlet orifices, and a second position wherein the diaphragm is not engaged with at least one of the outlet orifices.

2. The back pressure regulator of claim 1 wherein: the plurality of inlet orifices are disposed in a cluster in the center of the control surface; and the plurality of outlet orifices are disposed in one or more concentric rings around the cluster of inlet orifices.

3. The back pressure regulator of claim 2, wherein the plurality of outlet orifices are disposed in at least four concentric rings.

4. The back pressure regulator of claim 1, wherein an annular outlet cavity is formed in a top surface of the body which abuts the back surface of the orifice plate.

5. The back pressure regulator of claim 1, wherein a cross sectional area of the outlet cavity is no more than 57% of a cross sectional area of the inlet opening of the body.

6. The back pressure regulator of claim 4, wherein the outlet port communicates with the outlet cavity.

7. The back pressure regulator of claim 4, wherein at least one outlet orifice of the orifice plate is aligned with an edge of the outlet cavity.

8. The back pressure regulator of claim 8, wherein the inlet port includes a tapered portion adjacent the orifice plate.

9. The back pressure regulator of claim 8, wherein an included angle of the tapered portion of the inlet port is greater than or equal to 4 degrees.

10. The back pressure regulator of claim 1, wherein the inlet port turns through an angle of 90 degrees adjacent the orifice plate.

11. The back pressure regulator of claim 10, wherein the inlet port includes a tapered portion adjacent the orifice plate.

12. The back pressure regulator of claim 11, wherein an included angle of the tapered portion of the inlet port is greater than or equal to 4 degrees.

13. The back pressure regulator of claim 1, wherein an annular O-ring gland is formed in a top surface of the body which abuts the back surface of the orifice plate.

14. The back pressure regulator of claim 13, wherein the O-ring gland is configured with one recessed edge.

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