JPH0253660B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to valve assemblies, and more particularly to sanitary valves having gaskets that are field replaceable and can be cleaned without disassembly.

BACKGROUND OF THE INVENTION It is well known to provide linear motion valves with relatively soft gaskets that contact the valve seat to provide a tight seal. For example, in US Pat. No. 107,841, a rubber elastomeric material is bonded to a beveled or curved portion of a valve stem. U.S. Pat. No. 1,538,126 incorporates a copper cup-shaped contact member on the beveled surface of the valve stem. Copper is relatively soft and can closely conform to the shape of the valve seat. US Patent No.
The tips of the carburetor needle valves shown in Nos. 3326520, 3445089, and 3531086 are made of a material such as rubber, and are sealed in contact with the valve seat of the float chamber of the carburetor.

A common feature of known gaskets is that it is difficult to replace them in the field. Installing a new rubber or other resilient end or surface requires pulling over a relatively large cross-section of the valve stem.
Further, in the example of US Pat. No. 3,531,086, a portion of the valve stem is crimped to provide a somewhat permanent attachment to the rubber end. Other known designs require heating the gasket to attach it to the valve stem.

In the structure shown in US Pat. No. 1,538,126, etc., it is necessary to disassemble the stopper pin, nut, screw, etc. of the valve element and remove the gasket. To install the gasket, reverse the procedure. This disassembly and assembly work is time consuming and inefficient.

Known valves have gaskets that are difficult to replace;
Normally the valve stem and gasket are replaced as one unit. Usually only the gasket needs replacing, which is wasteful.

Another problem with the known valve stems and gaskets mentioned above is that they are unsuitable for food processing applications. Sanitary facilities should use non-corrosive materials such as stainless steel and certain synthetic resins. Furthermore, the valve should be easily cleanable to reduce non-productive time due to cleaning. For ease of cleaning, there should be a minimum number of crevices in which food particles can become trapped during use. Furthermore, the accumulated particles need to be easily washable during cleaning. Ideally, it would be desirable to eliminate the need to disassemble and reassemble the entire machine, including the valve element, and to be able to clean it with all parts attached. Known valve elements have crevices that trap food particles, and the crevices cannot be cleaned without decomposition over time. Reassembly will also be required.

SUMMARY OF THE INVENTION There is a need for a sanitary valve assembly in combination with a field-replaceable gasket to provide a contact seal to the valve seat, and to allow the valve assembly to be rapidly and efficiently cleaned in-situ.

SUMMARY OF THE INVENTION A linearly acting sanitary valve assembly in accordance with the present invention provides for field replacement of the gasket that seals against the valve seat. For this purpose, the valve device has a valve stem, and the valve stem has a valve stem plug and a valve stem shaft. The valve stem plug has an external truncated conical surface, the axis of the cone being coincident with the axis of the valve stem shaft. The frustoconical surface is between two axially spaced and laterally extending shoulders.

A gasket of relatively soft elastomeric material is associated with the valve stem to provide a tight seal to the valve seat. The gasket is fabricated as an annular ring of approximately rectangular cross section. The annular ring fits loosely into a mating outer surface of the valve stem plug to form a seat assembly. The gasket is provided with a conical portion extending from one end of the annular ring. The inner surface of the cone matches the frusto-conical surface of the valve stem plug. The outer conical surface of the gasket is substantially parallel to the inner conical surface, forming a hollow truncated cone. The gasket is axially restrained on the valve stem plug between the shoulders.

Several slots are provided in the hollow cone of the gasket to facilitate assembly of the gasket onto the valve stem. A slot extends from the conical end of the rectangular ring to form a plurality of resilient fingers. To assemble the gasket to the valve stem, push the gasket against the frusto-conical surface of the valve stem plug. The gasket fingers bend while passing through the small diameter shoulder at the top of the valve stem plug frustoconical surface. When the rectangular ring of the gasket contacts the shoulder on the bottom end of the valve stem plug frustum, the finger passes through the small diameter shoulder. The fingers elastically return to the undeformed position and the gasket is restrained between the shoulders.

The present invention makes the field replaceable gasket described above applicable for sanitary purposes. To this end, the dimensions of the gasket and valve stem plug are such that the gasket fits loosely over the valve stem plug, allowing relative axial and lateral movement. When the seat assembly closes against the valve seat, the gasket is pressed against the valve stem plug to form a seal. When the valve stem opens, a gap is formed between the gasket and the valve stem plug at the conical surface and shoulder. For this purpose, the cleaning fluid passes through the gap of the valve opened during cleaning and cleans the food particles that have accumulated during normal operation and on the parts.

To improve cleaning, the outer surface of the valve stem plug and the inner surface of the gasket ring are sloped in substantially the same direction as the conical surfaces of the valve stem plug and gasket. This reduces the flow resistance of the cleaning fluid between the gasket and the valve stem plug. The valve assembly can thus be cleaned in situ, eliminating non-productive disassembly and reassembly time.

Function: The valve of the present invention prevents a valve seat contacting gasket between the first and second shoulders of the valve stem.

A plurality of elastic fingers are formed on the gasket, and during assembly, the elastic fingers deform and pass through the small diameter shoulders, and after completing the passage, the fingers contact the conical surface between the shoulders.

By providing a loose axial and lateral engagement between the valve stem surface and the gasket to form a gap when the valve is opened, cleaning can be accomplished by simply flowing a cleaning solution.

EXAMPLES The following disclosure is detailed enough to enable one skilled in the art to practice the invention. The embodiments disclosed herein are merely illustrative, and the invention is applicable to other structures. The invention is limited only by the claims that follow.

In FIG. 1, a fluid control valve incorporating the present invention is shown. This valve is particularly useful in processing liquid and viscous foods. However, the invention is not limited to sanitary applications only.

The control valve 1 has a motor 3 attached to a bonnet portion 5. The lower end of the bonnet part 5 has a port 9,
11. An example design for assembling the control valve motor, bonnet, and valve body does not form part of this invention and is described in US Pat. No. 3,110,471.

The bonnet portion 5 guides the valve stem shaft 13 of the seat assembly 15 of the present invention. Motor 3 moves the seat assembly linearly along the longitudinal axis 16 of the valve stem. In FIG. 1 the valve is in the open position and fluid entering port 11 exits port 9, this direction being indicated by arrows 17,18.

In accordance with the preferred embodiment of the invention, the seat assembly includes a valve stem 21 shown in FIG. 2 and a gasket 23 shown in FIGS. The gasket is positioned on the valve stem as shown in FIGS.

As shown in FIG. 2, the valve stem 21 has a valve stem shaft 13 and a valve stem plug 25. A groove 27 is provided in the valve stem shaft 13 to engage a conventional sealing element (not shown). The free end 29 of the valve stem shaft is not relevant to the invention and is attached to the motor 3 by engaging known devices not shown in FIG.

In the illustrated example, the valve stem plug 25 has a frusto-conical surface 31, the axis of which coincides with the axis 16 of the valve stem shaft 13 shown in FIG. The preferred angle of the conical surface is 45°. The top of surface 31 forms a cylindrical surface 33. A shoulder 35 extends laterally from the cylindrical surface 33 to hold the gasket 23 in one direction on the valve stem.
is extended. In the preferred embodiment, the surface 37 of the shoulder 35 is not perpendicular to the valve axis, but extends approximately in the same direction as the surface 31.
The slope shall be 10°. The shoulder 35 is further provided with an outer chamfer 39. The base end of the tapered surface 31 coincides with the outer circumferential surface 41. In accordance with the present invention, surface 41 is not cylindrical, but is inclined approximately 5 DEG in substantially the same direction as surface 31. The functions of the slopes 37, 39, and 41 will be described later.
In order to retain the gasket on the valve stem and to support the gasket when pressed against the valve seat 19, a shoulder 43 having a surface 44 substantially perpendicular to the valve axis is provided with an inclined surface 4.
Extend horizontally from 1.

In order to use the valve of the present invention for sanitary and food applications, the selection of materials is important. Suitable materials include:
The valve shall be stainless steel, for example type 316 stainless steel.

In accordance with the present invention, valve 1 utilizes a field replaceable gasket 23 as shown in FIGS.
A material suitable for food use is TFE synthetic resin.
Gaskets of hard durometer elastomeric materials may also be used. The gasket has an annular ring 45 of approximately rectangular cross section. The ring inner surface 46 corresponds to the valve stem plug 41 as a bevel. The gasket ring is provided with an external chamfer 47 to contact and seal against the tapered valve seat 19.

Gasket 23 is formed with a hollow frusto-conical portion 49 extending from one end of ring 45. Conical part 49
has substantially parallel inner and outer surfaces 53,51. Inner surface 5
3 corresponds to the valve stem conical surface 31. A cylindrical surface 55 is formed at the free end of the frustoconical portion of the gasket and corresponds to the valve stem surface 33.

A plurality of slots 5 are provided in the truncated cone 49 to allow for quick and easy field replacement of the gasket 23.
7 will be provided. The slots extend from the surface 55 into the ring 45 and form a circular band of elastic fingers 59. To retain the gasket on the valve stem plug 25, an angled locking surface 61 is formed at the distal end of the finger 59. Locking surface 61 corresponds to valve stem ramp 37.

To assemble gasket 23 to valve stem 21, attach valve stem head 25 to gasket ring 45.
the valve stem chamfer 39 to the inner surface 5 of the finger.
3. As the valve stem is pushed further into the gasket, fingers 59 deform outwardly as they pass from surface 39 through shoulder 35. When the ring surface 62 contacts the shoulder 44, the finger returns to its undeformed position. The gasket is permanently retained between shoulders 35,43. The finger surface 61 cooperates with the stem 37 to prevent the fingers from opening.

Gaskets can be easily replaced in the field. The old gasket can be cut off from the valve stem with a knife, etc., and the new gasket can be assembled into the valve stem, which can be easily done in a short time without the need for any special tools.

As shown in FIG. 5, when the seat assembly is in the closed position, the chamfer 47 of the gasket 23 is aligned with the tapered valve seat 1.
9 to form a tight seal. Under this condition, the gasket is attached to the valve stem plug 25 with faces 41, 4.
6; 44, 62; 31, 53. Therefore, the fluid flow shown by arrow 17' does not occur.

The present invention further provides for in-situ cleaning of the seat assembly 15. To this end, the dimensional relationship between the valve stem plug 25 and the gasket 23 is such that when the valve is in the open position, the gasket loosely engages the valve stem plug. As shown in FIG. 6, the gasket is movable in a transverse axial direction relative to the valve stem plug, with the gap between shoulders 35, 43 being slightly larger than the length of the gasket. The gap formation between the gasket and the valve stem plug is indicated by the arrow 6 of the open control valve 1.
This becomes the fluid washing flow path shown by 3. arrow 65,6
7 goes through the gasket slot 57 to the ring 45
The path of the cleaning effect flow between the valve stem plug and the valve stem plug is shown. The sloping surfaces 41, 46 improve the direction of the flushing flow between the ring and the valve stem plug. Food particles that become attached to the valve assembly during normal operation are removed and there is no need for unproductive control or valve assembly disassembly.

The seat assembly 69 shown in FIGS. 7-9 includes a valve stem 7.
1, a gasket 73, and a valve seat 75. Gasket 73 has a ring 74 of generally rectangular cross section;
The outer diameter of the gasket 73 is larger than that of the gasket described above, and the gasket 73 has a large horizontal surface 77 that allows the gasket 73 to fit into the horizontal valve seat 7.
5, and there are no chamfers on the gasket and valve seat for sealing. In order for the valve stem 71 to have the same linear stroke as the aforementioned valve stem 21 and to use a gasket ring having the same thickness as the ring 45,
It is necessary to deeply machine the valve seat surface 75 as shown in FIG. A shoulder 79 projects laterally from the valve stem 71 to a dimension corresponding to the diameter of the gasket ring 74.

FIG. 10 shows another embodiment of the seat assembly of the present invention. The shoulder 85 of the valve stem 83 of the seat assembly 81 projects laterally in correspondence with the ring 87 of the gasket 85. To seal the gasket to the flat horizontal valve seat 90, an annular sealing bead 93 is formed on the underside 91 of ring 87, eliminating the need for a chamfer for sealing. In the embodiment shown in FIG. 10, the valve seat 90 is located higher than in the above-described embodiment, reducing machining.

Effects of the invention As made clear by the above, the sanitary valve according to the invention has a field replaceable gasket,
Solve the aforementioned problems. In accordance with the present invention, the gasket is formed with a plurality of resilient fingers for contacting the frusto-conical surface of the valve head. The frustoconical surface of the valve head has a laterally extending shoulder. To assemble the gasket to the valve head, the gasket is pushed into the valve head and the finger contacts and deforms the shoulder. Once past the shoulder, the finger springs back into contact with the shoulder and is restrained by the gasket valve. Holding the gasket loosely when the valve assembly is in the open position provides a self-cleaning effect due to liquid flow between the valve head and the gasket.

Although the present invention has been described with reference to embodiments, the present invention can be modified in various ways, and the embodiments and drawings are illustrative and do not limit the invention.

[Brief explanation of the drawing]

FIG. 1 is a side view, partially in section, of a fluid control device incorporating the sanitary valve assembly of the present invention; FIG. 2 is an enlarged side view, partially in section, of the valve stem of the valve assembly of the present invention; Figure 3 is an end view of the gasket of the valve assembly;
4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is a partial sectional view showing the valve assembly in the closed position, and FIG. 6 is a partial sectional view of the valve assembly in FIG. 5 in the open position. 7 is a sectional view showing another embodiment of the gasket, FIG. 8 is a partially sectional side view showing a valve stem combined with the gasket in FIG. 7, and FIG. FIG. 10 is a partial cross-sectional view of the valve assembly shown in the closed position, and FIG. 10 is a partial cross-sectional view of an assembly including a gasket according to another embodiment. DESCRIPTION OF SYMBOLS 1... Fluid control valve, 3... Motor, 5... Bonnet part, 7... Valve body part, 9, 11... Port, 13... Valve stem shaft, 15, 69, 81...
Valve assembly, 19, 75, 90... Valve seat, 21, 7
1, 83...Valve stem, 23,73,89...Gasket, 25...Valve stem plug, 31...Truncated conical surface, 33...Cylindrical surface, 35, 43...Shoulder, 41...Outer periphery Surface, 45, 74, 87... annular ring, 49... truncated conical portion, 57... slot, 59... finger.

Claims (1)

[Scope of Claims] 1. A valve stem and gasket assembly, comprising a valve stem having first and second circumferential shoulders for restraining the gasket therebetween, and a gasket having a plurality of elastic fingers. , wherein the finger passes through the first restraining shoulder under deformation conditions to facilitate assembly, and when not deformed, contacts the first restraining shoulder to prevent disassembly and restrain the gasket between the two shoulders. Valve stem and gasket assembly. 2. The assembly of claim 1, wherein the valve includes a valve stem shaft and a valve stem plug, and the shoulder for restraining the gasket is formed on the valve stem plug. 3. The valve stem plug is formed with a truncated conical surface between both shoulders, and the gasket fingers are substantially parallel to the truncated conical surface of the valve stem plug. assembly. 4. The first laterally extending shoulder is provided with an outward bevel in the general direction of the restraining gasket, and the gasket finger end face is provided with a cooperating bevel to prevent disassembly. Assembly according to paragraph 3. 5. The assembly of claim 3, wherein the restrained gasket loosely engages axially laterally onto the valve stem plug. 6. The pace end outer surface of the valve stem plug frustoconical surface is sloped in substantially the same direction as the frustoconical surface, and the gasket is formed with an annular ring having a cooperating internal slope. The assembly according to item 5. 7 A fluid control device comprising: a housing having an inlet/outlet port and a valve seat; a valve stem mounted within the housing and having first and second axially spaced circumferential shoulders; a gasket that is prevented from being engaged between the second shoulders and contacts the valve seat, and the gasket is provided with a plurality of elastic fingers so that the gasket does not deform through the first shoulder under deformation conditions for assembly. contact with the first shoulder under conditions to prevent decomposition;
1. A fluid control device comprising a motor device mounted on a housing to perform linear motion to sealingly engage and release a valve stem and a gasket to and from a valve seat to stop or allow fluid flow within the device. 8. The apparatus of claim 7, wherein the valve seat is tapered and the gasket is formed with a beveled surface for sealing engagement with the valve seat. 9. The device of claim 7, wherein the valve seat is flat and the gasket is formed with a flat surface for sealing engagement with the valve seat. 10. The device according to claim 7, wherein the valve seat is flat and the gasket is formed with a sealing bead for sealing engagement with the valve seat. 11 The valve stem is provided with a valve stem plug and a valve stem shaft, and the valve stem plug is provided with the first and second valve stem plugs.
8. The device of claim 7, wherein the gasket forms a frustoconical surface between the shoulders of the valve stem plug, and the resilient fingers of the gasket conform to the frustoconical surface of the valve stem plug. 12 the bottom end of the valve stem plug frustoconical surface contacts an outer surface that slopes in substantially the same direction as the frustoconical surface;
The gasket is formed with an annular ring having an inclined inner surface that conforms to the outer inclined surface of the valve stem plug, and the ring is loosely engaged in an axially lateral direction to the valve stem plug when the gasket is not in contact with the valve seat. A device according to claim 11, characterized in that a gap is formed between the gasket and the valve stem plug, so that when cleaning the control device, a cleaning fluid flows between the gasket and the valve stem plug to enable cleaning without disassembly. . 13. A method for permanently assembling a gasket to a valve stem, the method comprising: providing a valve stem having first and second laterally extending and axially spaced circumferential shoulders; providing a gasket having a plurality of resilient fingers that deform when contacted with the valve stem; pushing the gasket over the first shoulder and onto the valve stem;
This causes the resilient fingers to be assembled over the first shoulder and resiliently return to contact the first shoulder and permanently restrain the gasket between the first and second shoulders. A method of assembling a gasket onto a valve stem, characterized in that: 14 The valve stem has a valve stem plug and a valve stem shaft, the valve stem plug has a truncated conical surface between the first and second shoulders, and the gasket finger is attached to the truncated end of the valve stem plug. 14. Method according to claim 13, characterized in that it is adapted to a conical surface. 15. A gasket for use with a valve stem having first and second restraint shoulders, wherein the gasket deforms to facilitate passage through the first restraint shoulder of the valve stem and facilitates assembly; A gasket having a plurality of elastic fingers that contact a first restraining shoulder to prevent disassembly, the elastic fingers being fitted and held between the shoulders of the valve stem when the elastic fingers are relaxed. . 16. The gasket of claim 15, wherein said resilient fingers are substantially parallel to a frustoconical surface of said valve stem. 17. Claim 15, wherein the resilient fingers have an end surface with an inclined surface that coincides with and cooperates with an inclined shoulder surface of the valve stem to prevent disassembly. gasket. 18. The gasket of claim 15, further comprising an annular ring with a beveled interior surface that matches the beveled exterior surface of the valve stem.