US 3675849 A
An in-plant cleaning system having a centrally located power unit and a plurality of outlet cleaning stations. The power unit consists basically of a motor, a pump and a conventional unloader. The system is provided with at least one combination of a conventional surge suppressor, a check valve and means to vent reverse pressure slowly back into the system to prevent water hammer. In the preferred embodiment one such combination is provided at each outlet cleaning station along with the cleaning gun.
Claims available in
Description (OCR text may contain errors)
0 United States Patent 1151 3,675,849
Boylan 1 July 11, 1972 54] IN-PLANT CLEANING SYSTEM 3,447,557 6/1969 Phelps et al .,137/207 Inventor: J p Boylan, Ashland. Ohio FOREIGN PATENTS 0R APPLICATIONS 1 Assigneer McNeil Corporation, Akron, Ohio 970,852 9/1964 Great Britain ..137/207  filed: 1970 Primary Examiner-Lloyd L. King  App]. No.: 25,989 Attorney-Hamilton, Renner& Kenner 57 ABSTRACT  US. Cl ..239/l24, 137/207 1  Int. Cl ..B05b 9/00 An in-plant cleaning system having a centrally located power  Field of Search ..137/207; 239/124 unit and a plurality of outlet cleaning stations The power unit consists basically of a motor, a pump and a conventional un-  References u loader. The system is provided with at least one combination of a conventional surge suppressor, a check valve and means UNITED STATES PATENTS to vent reverse pressure slowly back into the system to prevent water hammer. In the preferred embodiment one such coml,459,775 6/1923 Lamer 137/207 bination is provided at each outlet cleaning Station along with 2,742,928 4/1956 Luzynsk1 1 37/207 X the cleaning gum 3,246,845 4/1966 Techler et al. ....239/l24 X 3,292,661 12/1966 Everett 1 37/207 X 6 Claims, 3 Drawing Figures CLEANING STATIONS CENTRAL POWER UNIT CLEANING STATION P'A'TE'N'TEDJUL 1 1 I972 3 675,849
CLEANING STATIONS CLEANING STATIONS CENTRAL I POWER UNIT FIG. 1
/2I FROM CENTRAL UNIT -'5l l-SPRAYGUN /40 ,f FROM ;E CENTRAL- f UNIT SPRAY GUN /40 INVENTOI Q 3 OSEPH S. BOYLAN BYM, W7
A T TORNEYS lN-PLANT CLEANING SYSTEM BACKGROUND OF THE INVENTION This invention relates to an in-plant cleaning system having a centrally located power source controlling a plurality of stations throughout a factory or the like. Specifically, this invention relates to such an apparatus which avoids the instability and hammer problems prevalent in the prior art.
Laboratories, factories and the like often need to be equipped with some type of cleaning system to wash down the floors, equipment or other items when desired. Two approaches are commonly utilized. In one system, a pluralityof portable units are located throughout the plant for use when the need arises. However, these units, each comprising a motor, pump, reel, hosing and other accessories, are quite costly. Further outlets must be provided randomly around the plant so that the portable unit can receive a source of fluid under pressure. In the case of an emergency wash-down, the securing, moving, and attaching of the portable unit may require a prohibitive amount of time.
The second approach is to provide a centrally located pumping system wherein a pump continually feeds a plurality of outlets. Of course, it is understood that during the majority of the time, no demand is being made on such a pump. Therefore, a conventional regulator is usually provided to bypass the outlets and return the water to a tank which feeds the pump. This system has numerous disadvantages, all precipitated because the pump is caused to operate against a full head of pressure at all times. This necessarily wastes power and stresses vital components of the pump such as the packing elements. Further, as the water is recirculated during periods of little or no demand, undesirable heat is generated in the water.
In order to alleviate some of the problems encountered in the second approach described above, a conventional unloader pressure regulator (commonly referred to as an unloader) has at times replaced the standard regulator. This allows the pump to operate, during system inactivity, against very little pressure meaning no wasted power, no pump stress, and no generated heat. However, use of a conventional unloader creates additional problems: system instability or water hammer. I
The system instability and water hammer can best be described by first discussing a parameter known as system capacitance. The measure of system capacitance is a measure of the energy stored in the system. Such energy can be stored by an item introduced into the system such as a conventional surge suppressor. Similarly, the same effect can be encountered when an extensible hosing or conduit is utilized as the conveying medium. In either case, the use of an unloader often renders the system unstable as the unloader seeks or hunts" its proper level, dependent on the amount of capacitance in the system.
When steel piping is used in a system having no surge suppressors, the stability problem is alleviated since essentially zero capacitance is presented; but two additional problems are created. First, the nerve-racking and often damaging water hammer is encountered when a gun is suddenly shut off and a back pressure is created; and second, the unloader utilized may cease to unload. The latter occurs when there is a small demand in the system such as the inevitable slow dripping leak at one or more of the outlets. When such is the case, the pressure on the input side of the unloader slowly approaches the pressure on its output side, and when the two pressures eventually equalize, the unloader will, in effect, hang-up.
Adding capacitance to the essentially zero capacitance steel pipe system (in the form of a surge suppressor) will only cause the aforementioned instability.
SUMMARY or THE INVENTION It is thus a primary object of the present invention to provide an in-plant cleaning system having controlled capacitance so that both unloader oscillation or instability and system water hammer are avoided.
It is another object of the present invention to provide an inplant cleaning system, as above, which eliminates unloader failure due to slight demandssuch as a slow leak in the system.
It is still another object of the present invention to provide an in-plant cleaning system, as above, in which there is no power wasted, no extraordinary pump stressing, and no unnecessary water heat build-up.
It is a further object of the present invention to provide an in-plant cleaning system, as above, which is easy to install and more economically operable than existing centrally powered systems and portable units.
These and other objects which will become apparent from the following specification are accomplished by structures hereinafter described and claimed.
In general, a central power unit consisting essentially of a motor driven pump and conventional unloader provides a plurality of remote outlet stations with water under pressure through a rigid piping system. In the preferred embodiment each outlet station has a conventional spraying gun, a surge suppressor, a check valve, and means to slowly vent pressure back into the system. Many types of vent means can be provided, two of which are described herein; one being in the check valve itself, and the other being in a bypass line. In either situation, the slow venting of the stored pressure back to the system controls system capacitance to accomplish the aforementioned objectives.
BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS An in-plant cleaning system according to the concept of the present invention is indicated generally by the numeral 10 in FIG. 1 as consisting of a central power unit 20 and a plurality of cleaning stations 30. The basic power unit 20 includes a source of water or fluid input means, a pump, motor, holding tank and a regulating device such as an unloader, all of which function in a manner well known in the art toprovide water under pressure through the conduit piping network 21 to stations 30. While piping network 21 could be of many types, standard steel pipes and fittings are contemplated.
The elements of the power unit 20 are designed and connected so that in instances on non-use, the unloader will perform its function allowing the pump to work against very little pressure. However, when a demand is made at one or more of the cleaning stations 30, the pump must be capable of providing suitable outputs. It has been found, for example, that in a system having approximately twenty stations 30 spread over a distance of 500 feet in a factory, a 35 gallon per minute positive displacement or reciprocating pump producing a pressure of 1,000 p.s.i. is necessary. Depending then on the number of stations 30 and other system parameters, one skilled in the art could quite readily determine the type or size pump, motor,
and other elements of the power unit 20, as well as the size of the piping 21.
One form of cleaning station 30 according to the present invention is shown in FIG. 2. A flexible hosing 31 receives the water from pipe network 21 and carries it to a propelling gun indicated generally by the numeral 40 in FIGS. 2 and 3 and having an appropriate nozzle, detergent injector and the like all conventional items. While different systems would dictate the parameter requirements, a short barreled gun having a nozzle in the range of five to ten gallons per minute would be typical.
Provided within network 21 is a check valve 32 oriented in such a manner so as to permit normal or primary flow only in the direction toward a conventional surge suppressor 33 (to the right in FIG. 2). Check valve 32, as shown in FIG. 2, is provided with a small vent hole 34 therein which allows excess pressure to be vented slowly back into the system. When the gun is shut off suddenly, the check valve 32 will open and the surge suppressor 33 will absorb the kinetic energy of the water flowing through piping network 21, thereby preventing water hammer. As the pressure pulse reverses, the check valve will close and the pressure slowly discharge back to the system through vent 34. When a gun is turned back on the system pressure drops rapidly but the valve 32 will prevent rapid recharging of the system which is the cause of unloader instability. By providing a number of surge suppressors in the system (preferably one at each station 30), rapid recycling of the unloader is precluded, such recycling occurring due to prevalent slow leaks in the system. In the past, the pressure drops due to such leaks had to be replenished by the pump; however, the surge suppressor 33 is able to replenish the system thus prolonging the period between rechargings by the pump.
Shown in FIG. 3 is another manner by which the objectives of the invention may be accomplished. There, instead of providing a vent in the check valve 32, a small orifice 35 is provided in a by-pass conduit or line 36. The orifice 35 acts in the same manner as the vent 34 as described above to preclude water hammer, unloader instability, and unloader failure.
It should thus be evident that a system constructed according to the concept of the present invention as described herein, accomplishes the aforementioned objectives and otherwise substantially improves the in-plant cleaning system art.
What is claimed is:
l. A cleaning system having a central power unit including pump means, regulating means, and fluid input means; at least transmitting the fluid to an item to be cleaned, surge suppressor means, means to permit primary fluid flow only from said conduit means to said surge suppressor means, and vent means selectively permitting restricted flow from said surge suppressor means to said spray gun.
2. A cleaning system as in claim 1 wherein said means to permit primary fluid flow only from said conduit means to said surge suppressor is a check valve.
3. A cleaning system as in claim 2 wherein said vent means is included in said check valve.
4. A cleaning system as in claim 2 having a by-pass conduit, and wherein said vent means is within said by-pass conduit.
5. A cleaning system as in claim 4 wherein said vent means is an orifice.
6. A cleaning system comprising a central power unit; said central power unit including fluid input means, pump means to supply fluid under pressure to the system, and regulating means permitting said pump means to operate against little pressure when no demand is made on said pump; at least one cleaning station; and conduit means transmitting fluid under pressure from said central power unit to said cleaning station; said cleaning station including a spray gun receiving fluid from said central power unit and selectively transmitting the fluid to an item to be cleaned, surge suppressor means, means within said conduit means between said spray gun and said surge suppressor means and between said central power unit and said surge suppressor means permitting primary fluid flow only in a direction toward said surge suppressor means, and vent means to impede instability of said regulating means by selectively permitting flow from said surge suppressor means to said spray gun when said spray gun is not transmitting fluid to an item to be cleaned.