Fluid handling – With leakage or drip collecting
Reexamination Certificate
2000-08-22
2003-01-14
Walton, George L. (Department: 3753)
Fluid handling
With leakage or drip collecting
C137S015050, C137S015060, C137S015110, C137S312000, C137S315090, C137S625500, C251S063500, C092S013800
Reexamination Certificate
active
06505639
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to a three way valve having a positive shut off valve for mixing or diverting a flowable material. More particularly, the novel hygienic three way valve is provided for mixing or diverting flowable materials while avoiding contamination of the flowable material by employing a positive controlled valve having a tapered valve seat of a substantially frustro-conical configuration in combination with a substantially cylindrical piston sealing head actuated by a piston positively controlled by fluid activation.
The fluid activated piston of the novel hygienic three way valve preferably employs a pneumatically controlled piston having a pneumatic activation chamber at one end and a product chamber at the other end. The pneumatically activated piston is disposed through the valve body, which valve body includes a leak detection port disposed between the pneumatic activation chamber and the product chamber with a first sealing means disposed between the leak detection port and the pneumatic activation chamber and a second sealing means disposed between the product chamber and the leak detection port.
The leak detection port, in combination with the first and second sealing means not only provides early detection of seal failure but also identifies the location of the defective seal without allowing contamination of the fill material with contaminants in the pneumatic air or activation fluids in the chamber for activating the positive controlled piston. The combination of the air or fluid in the activation chamber with cups on the piston allows the piston to not only positively open and close the valves, but also to assume an infinite number of positions between the valves.
The novel hygienic three way valve not only prevents contamination of the flowable fill material with the fluids used to activate the positive controlled piston for opening and closing the positive control valve, but also provides for the mixing or diversion of fluids introduced to the three way valve by utilizing a second tapered valve seat having a substantially frustro-conical configuration disposed axially adjacent to the first tapered valve seat to utilize both an upper and lower portion of the substantially cylindrical piston sealing surfaces of the sealing head attached to the positively controlled piston.
The first and second tapered sealing seats are disposed in a mixing or diversion chamber disposed below an inlet chamber communicating with a product introduction port. A second port communicates with the mixing or diversion chamber intermediate the first and second sealing seats to provide a mixing or diversion chamber which also communicates with an outlet port. The novel hygienic three way valve is preferably segmented into a fluid cylinder or chamber for housing the positive controlled piston activation means, a main body, having a first or inlet product chamber and a second or product mixing or diversion chamber, and a port disposed intermediate the tapered ends of the mixing or diversion chamber and an outlet port in axial alignment with the mixing or diversion chamber.
The novel three way hygienic valve includes, in the preferred application, flanged connections between the fluid activation chamber, the main body of the three way valve, and the outlet port. In addition, flanges are provided for interconnections between the first inlet port leading to the first product chamber and the product port communicating with the second product chamber, as well as at both ends of the outlet port. Optionally, the main body can be further segmented and additional flange connections can be provided between the first product chamber and the second product chamber, as well as the provision of additional mixing chambers along the axial length of the sealing piston, as well as additional sealing heads of decreasing diameters disposed axially along the length of the novel hygienic valve. The combination of axial aligned sealing heads in such applications can provide a plurality of mixing and/or diversion zones in the novel valve, as well as providing a positive shut off of all of the mixing chambers from the outlet nozzle by the retraction of the positively controlled piston for controlling multiple valves.
The novel hygienic mixing or diversion valve of the invention may include a plurality first and second seals for providing a determination of seal failure and a plurality of leak detection ports between the various axially aligned mixing or diversion chambers. The novel hygienic three way valve is preferably constructed of a seamless material, such as stainless steel, glass or other material that can be easily cleaned and has a smooth, seamless surface that prevents the build-up of bacteria or other contaminants that would have a deleterious effect upon fill products requiring the highest hygienic handling consistent with food, medical and pharmaceutical preparations and processing.
2. Description of Related Prior Art
A wide variety of product mixing or diversion valves are known in the prior art. Some of these diversion valves are made of stainless steel, glass and other seamless materials, but these prior art diversion valves do not include a positive shutoff valve provided by a pneumatically activated piston having a sealing head of a substantially cylindrical configuration in combination with a pair of tapered sealing seats of a frusto conical configuration in combination with a leak detection port for providing a positive identification of seal failure before deterioration of the seal has resulted in contamination of a fill product with the fluid for activation of the piston.
In the prior art, seal failure has resulted in the contamination of the fill product with the fluids for activating the product valve piston. The fluids typically utilized in the food processing industry have been partially pneumatically controlled and partially spring controlled pistons and when such prior art pistons fail, the fill product is contaminated with pressurized air from an air pressure source and the contaminants generally found in pressurized air which typically include dust, bacteria, oil and other small particulate matter as well as lubricants employed with springs in the piston activation chamber. Typically, such seal failures have resulted in shutting down the production line and in some cases, recall of defectively packaged products.
None of the know prior three way mixing and diversion valves have provided a positive leak detection means for providing advanced warning of a seal failure or provided a failsafe seal that would prevent the contamination of the fill product with the pneumatic fluid pressure and spring combination for operating the product dispensing piston. Further, none of the known prior art utilizes a positive control valve in combination with the pneumatic piston, which provides a tapered seat for positively controlling the dispensation of a fill product without displaying some dripping or bleed through of product around the piston. Such problems are common in the food processing industry, where stainless steel pistons are typically utilized to exert pressures on compressible fluids utilized to dispense a flowable product which is obviated by the present invention in allowing the piston to free float and not compress the fluid when the piston is operated in applications where closure of one of the valves is not required. Further in the prior art stainless steel pistons have not utilized a rubber or an elastomeric sealing head in combination with tapered sealing seats disposed in the path of flow of the dispensed flowable product.
In a prior art search no patents were uncovered utilizing a novel three way valve similar to that of the present invention with a leak detection port. Instead prior art was uncovered pertaining to leak detection ports and devices and three way valves. The most relevant prior art pertinent to leak detection ports pertained to leak detection devices used in gas flow applications such as Matthews U.S. Pat
Breneman William D.
Breneman & Georges
Georges Peter J.
Walton George L.
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