Surge suppression apparatus

Abstract: A surge suppression apparatus including a housing (12) and a flexible diaphragm (14) dividing said housing (12) into first and second sub-chambers (27a, 27b), the first sub-chamber (27a) having connection means (28, 30) for connecting the first sub-chamber to a supply of liquid under pressure, the second sub-chamber (27b) containing a gas under pressure, and, a gas reservoir (16) in communication with the second sub-chamber (27b) so as, in use, to provide an effective volume which is substantially larger than that of the second sub-chamber (27b).

Description: Technical Field This invention relates to a surge suppression apparatus. More particularly, but not exclusively, the invention relates to apparatus for suppressing the effects of pressure variations in a liquid, for example paint, supplied under pressure along a supply line by a reciprocating pump. Background Art It is known to provide a surge suppressor which has an air sub-chamber volume which is greatly in excess of the volume of a liquid sub-chamber in order to minimise the differential pressure change experienced in the air sub-chamber resulting from the flexure of the diaphragm due to a change (normally a reduction ) in the liquid supply line pressure thereby minimising any surge of the liquid, see for example European Patent Application No. EP 0 707 173 A1. Document US-A-4 556 078 describes a further embodiment of a surge suppression apparatus corresponding to the preamble of claim 1. Such surge suppressors have the disadvantage of being bulky thereby limiting their usefulness in the case of large numbers of suppressors and in working environments with limited space. It is an object of the present invention to provide a surge suppressor which mitigates this disadvantage whilst maintaining the advantages of the aforementioned known surge suppressors. Brief Summary of the Invention According to the present invention there is provided a surge suppression apparatus including a housing and a flexible diaphragm dividing said housing into first and second sub-chambers, the first sub-chamber having connection means for connecting the first sub-chamber to a supply of liquid under pressure, the second sub-chamber containing a gas under pressure, and, a gas reservoir in communication with said second sub-chamber so as, in use, to provide an effective gas volume which is substantially larger than that of said second sub-chamber, said gas reservoir being positioned remote from said second sub-chamber and being connected thereto by pipe means, and, the apparatus including a gas supply of said gas under pressure directly connected to said second sub-chamber so that gas from said supply may enter the second sub-chamber, when necessary, without having first to pass through said gas reservoir. Conveniently said first and second sub-chambers are of similar volume when the diaphragm is in a rest position. Desirably the second sub-chamber is provided with a pressure regulation means. Ideally the pressure regulation means is an active valve pressure regulation means. Desirably the liquid is paint. Conveniently there is provided an isolation valve between the gas reservoir and the second sub-chamber. Brief Description of the Drawings An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a part-schematic end view of a surge suppression apparatus according to the present invention; and Figure 2 is a partial sectional view of the surge suppression apparatus of Figure 1. Description of the Preferred Embodiment A surge suppression apparatus 10 includes a housing 12, a circular, flexible diaphragm 14 and an air reservoir 16. The housing 12 comprises first and second housing components 18, 19. Each housing component 18, 19 has a convex part-spherical dished portion 20, 22 and a substantially circular rim portion 24, 26. The housing portions 18, 19 are joined at their respective rim portions 24, 26 such that their respective dished portions 20, 22 define an internal chamber 27. The diaphragm 14 is held at its periphery between the rim portions 24, 26 so as to divide the internal chamber into first and second sub-chambers 27a, 27b. The first housing component 18, the lower component in the orientation as shown in the Figures, has an inlet union 28 and an outlet union 30 so as to, in use, allow the passage of a liquid therethrough. The second housing component 19 has a substantially cylindrical casing 32 projecting outwardly from the highest point thereof and a connection port 34 of the internal chamber 27 juxtaposed the casing 32. The casing 32 contains a pressure regulation means 35 and has a compressed air supply 36 connected, via an inlet 36a, thereto. An outlet port 37 from the pressure regulation means 35 projects perpendicularly from the casing 32 near the base thereof. A pipe 38 connects the air reservoir 16 to the port 34 and an isolation valve 40 is mounted in the pipe 38 close to the air reservoir 16. In use, a reciprocating pump (not shown) is used to pump liquid through the first sub-chamber 27a via the inlet and outlet unions 28, 30. Such a reciprocating pump does not have a constant output pressure over a pump cycle. During pump stroke reversal the pressure in the first sub-chamber 27a drops momentarily causing the diaphragm 14 to be deflected downwardly, the pressure in the second sub-chamber 27b exceeding that in the first sub-chamber 27a. The communication between the second sub-chamber 27b and the air reservoir 16 increases the volume of gas in the system and thereby increases the capacity of the apparatus to minimise variations in the pressure of fluid from the first sub-chamber 27a. It has been found that an air reservoir capacity of 8ℓ is sufficient to smooth pressure variations from a 1.5ℓ surge suppressor utilising any size of pump commonly used in such liquid delivery systems. The isolation valve 40 can be used to isolate the air reservoir 16 from the surge suppressor 10 in order to permit partial venting and/or repressurisation of the system or to replace the air reservoir 16 or carry out maintenance upon the surge suppressor 10. In a second embodiment (not shown) there is no pressure regulation means 35 and the surge suppression apparatus will be a sealed volume of pressurised gas, this is known as a static surge suppression apparatus.

Claims: A surge suppression apparatus including a housing (12) and a flexible diaphragm (14) dividing said housing (12) into first and second sub-chambers (27 a , 27 b ,), the first sub-chamber (27 a ) having connection means (28, 30) for connecting the first sub-chamber to a supply of liquid under pressure, the second sub-chamber (27 b ) containing a gas under pressure, and, a gas reservoir 16 in communication with said second sub-chamber (27 b ) so as, in use, to provide an effective gas volume which is substantially larger than that of said second sub-chamber (27 b ), the apparatus being characterised in that said gas reservoir 16 is positioned remote from said second sub-chamber (27 b ) and is connected thereto by pipe means (38), and, the apparatus includes a gas supply of said gas under pressure directly connected to said second sub-chamber (27b) so that gas from said supply may enter the second sub-chamber (27b), when necessary, without having first to pass through said gas reservoir (16). A surge suppression apparatus as claimed in claim 1 characterised in that said first and second sub-chambers (27a, 27b) are of similar volume when the diaphragm (16) is in a rest position. A surge suppression apparatus as claimed in claim 1 or claim 2 characterised in that second sub-chamber (27b) is provided with a pressure regulation means (35, 36) for controlling the gas pressure therein in use. A surge suppression apparatus as claimed in claim 3 characterised in that said pressure regulation means includes an active valve pressure regulation means (35). A surge suppression apparatus as claimed in any one of the preceding claims characterised in that there is provided an isolation valve (40) between said gas reservoir (16) and said second sub-chamber (27b) to permit the communication between said gas reservoir and said second sub-chamber to be broken. A surge suppression apparatus as claimed in claim 5 characterised in that said isolation valve (40) is mounted in said pipe means (38) between said gas reservoir and said second sub-chamber, adjacent said reservoir (16), to permit said gas reservoir (16) to be disconnected from said second sub-chamber (27b).

Inventors: ROGERS JOHN ANTHONY, ROGERS, JOHN ANTHONY
Applicants: LOMBARD PRESSINGS LTD, LOMBARD PRESSINGS LIMITED
Application year: 2000
Main classification: F16L55
IPC codes: F16L55, F04B11