Pumps – Motor driven – Fluid motor
Reexamination Certificate
2000-09-29
2002-11-05
Pelham, Joseph (Department: 3742)
Pumps
Motor driven
Fluid motor
C417S395000
Reexamination Certificate
active
06474961
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a diaphragm pump.
A diaphragm pump is known from DE 39 40 629 A1. It consists of a housing body that can be closed on both sides with a cover. Two facing diaphragm recesses each provided with one diaphragm are integrated in the housing body. Both diaphragm recesses are connected by a valve unit. Diaphragm recesses are also provided for the covers, such that pump chambers allowing the movements of the diaphragms are created when the covers are placed on the housing body. Furthermore, four check valves are present that have the same functional direction as the diaphragms. The check valves are housed in valve chambers that are located in both the housing body and the covers.
Although due to the same functional direction of the diaphragm and check valve, the diaphragms are easily accessible when the covers are removed; a disadvantage is that the check valves drop out of the valve chambers. Because the check valves consists of balls with a spring tension, the balls are propelled in normal fashion out of the valve chambers. Thus, maintenance can be carried out only with additional auxiliary means. The same is true for the assembly. Furthermore, a dual diaphragm pump is known from AS 27 26 674 or from U.S. Pat. No. 3,652,187, which is incorporated herein by reference. A dual diaphragm pump has a housing that incorporates two diaphragms and a control valve. The diaphragms divide the chambers of the diaphragm pump into drive chambers and pump chambers. Flow valves are assigned to the pump chambers. On each side, the housing is closed with a housing cover. The control valve is automatically moved at the end of each reciprocating stroke between two alternating positions to reverse fluid flow to the pump and thereby causes the pump to reciprocate.
The disadvantage is that the dual diaphragm pumps are not controlled with sufficient accuracy by the control valve. Furthermore, the suction and discharge valves are insufficiently seated in the housing such that the dual diaphragm pump is difficult to maintain and repair.
From the IT catalog of the company DEBEM: BOXER pompe a membrana azionate ad aria compressa [diaphragm pump actuated by compressed air], May 1988, pages 1 to 12 is known. This dual diaphragm pump includes two dual diaphragms. Each dual diaphragm is surrounded by an extra housing that is connected by piping and arranged on a base frame. One check valve is installed above each valve housing. A cubic housing can be used in place of the base frame.
The disadvantage is that essentially the entire dual diaphragm pump needs to be taken apart to inspect or repair the dual diaphragm pump. An additional disadvantage is that the pump requires a substantial amount of space.
SUMMARY OF THE INVENTION
The object of the invention is to provide a diaphragm pump wherein assembly and maintenance of the pump are easier and simpler.
According to the invention, a dual diaphragm pump includes a central housing having a pair of opposed housing surfaces, and a pair of covers each having a cover surface mated to a respective housing surface. Each surface has a diaphragm recess and a pair of valve recesses, the assembly having two pumping chambers with diaphragms therein and four valve chambers with check valves therein.
The advantages achieved with the invention consist basically in that through the two removable covers, the diaphragm body elements as well as the check valves become easily accessible for maintenance purposes. For inspections or repairs, the check valves simply need to be removed from the valve recesses of the housing and thereafter either cleaned or replaced by new ones or can easily be inserted during assembly. Cumbersome handling with springs and the like is not required. The two valve chambers are formed and the check valves fully taken in upon closing the center part of the housing with the two housing covers. It should be emphasized that by arranging the check valves on one side next to the housing chamber recesses, the pump can be built in a small and compact manner.
Two dual-path valves can be located in the center part of the housing. This increases the control accuracy.
One or more center parts of the housing or one or more diaphragm body elements can be used, creating a multiple diaphragm pump. Typically, two facing diaphragm body elements are used for a dual diaphragm pump. The diaphragm body elements can be designed as dual diaphragm body elements.
The housing can be designed as a compact housing. Externally, the compact housing looks like a monolithic block. This ensures that the housing can safely withstand both static and dynamic loads. The compact housing can be designed in a cubic shape. The cubic shape allows for several compact housings to be placed next to one another such that several dual diaphragm pumps can function in tandem in the smallest possible space.
At least partially, channels for flow can be positioned on the inside of the central housing body, in the elemental surface areas of the housing and in the interior elemental surface areas of the covers. These channels for the flow form complete and continuous flow paths when the housing cover is placed on the central housing unit. This saves the very elaborate installation of individual lines between the parts of the dual diaphragm pump.
Each check valve consists of a one-side open valve seat for the check valve. The valve seat for the check valve is built like a running wheel cage for hamsters and consists of two rings at opposite ends that are connected by interim rods. One ring exhibits an opening such that a valve ball can be inserted through it. The other ring has an opening such that the ball can be supported. During assembly, the check valve seats in the shape of hamster cages are simply plugged into the housing valve recesses. Before that, the valve ball is inserted. When the respective covers are placed on the pump body, the full valve chamber, which then surrounds the check valve, is formed. For inspection or repair of the check valve, it is only required to take out the check valve seat with the valve ball and to clean it or replace it with another. This reduces the effort for assembly, inspection and repair to a minimum. The same applies to the dual diaphragms.
The first and second housing cover can each be attached to the central housing unit using at least one screw element. This enables a removal of the housing cover for inspection and repair purposes.
The central housing unit and the housing cover may consist, at least in part, of synthetics and/or metal. It allows for the option to produce the entire housing of synthetics or of metal. However, it is also possible to make the central part of synthetics and the two covers of metal, or the central part of metal and the two covers of synthetics, or the central part and one cover of metal and the second cover of synthetics. The materials and material combinations to be used depend on the respective conditions during use.
For flow volumes of 25 to 30 liters per minute, the compact housing may have a length of between 130 and 170 mm, a height of between 70 and 95 mm and a width of between 70 and 95 mm. Preferably, the compact housing is 143 mm long and 81×81 mm high×wide.
REFERENCES:
patent: 4172698 (1979-10-01), Hinz et al.
patent: 4496294 (1985-01-01), Frikker
patent: 5232352 (1993-08-01), Robinson
Schmeing Josef
Timmer Herbert
Timmer Oliver
Campbell Thor
Milde & Hoffberg LLP
Pelham Joseph
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