Patent Application
20060045759
1. Field of the Invention
The present invention is broadly concerned with improved piston pump units equipped with a dual-hopper product feeding assembly which improves pump efficiency and lessens the required floor space for the pump. More particularly, the invention is concerned with such piston pumps as well as the dual-hopper assemblies used with the pumps and related retrofit assemblies which can be mounted on existing piston pumps. In preferred forms, the dual-hopper assemblies include a lower vacuum hopper with a permanently interconnected and substantially coaxially mounted upper atmospheric pressure hopper; a passageway is provided between the upper and lower hoppers, together with the selectively operable valve unit.
2. Description of the Prior Art
Piston-type pumps have long been available for the processing of foods and other valuable products. Piston pumps are known to be especially gentle with such products, and therefore are favored over vane or screw pumps. For example, Marlen Research Corporation has commercialized dual-piston pumps which have outstanding efficiencies while avoiding product degradation. Many of these pumps are of the vacuum variety, i.e., the pumping is conducted under subatmospheric conditions in order to deaerate the product during processing. See, e.g., U.S. Pat. Nos. 5,479,847 and 5,474,101.
Piston-type vacuum pumps include an upstanding, permanently attached vacuum hopper which receives product and delivers it to a lower pumping chamber. Generally speaking, in order to obtain commercial-scale throughputs, it is necessary to also provide an auxiliary atmospheric pressure hopper next to the pump. An elongated tubular conduit extends between the bottom of the auxiliary hopper and the vacuum hopper, and serves to convey product from the auxiliary to the vacuum hopper.
This conventional approach presents a number of practical problems. First of all, the existence of the separate atmospheric hopper takes up valuable floor space in a processing plant. In many instances floor space is more valuable than the space above a pump, i.e., many plants are constructed with high ceilings allowing fabrication of upper catwalks or dumping devices, whereas floor space is at a premium.
Additionally, use of a conduit between the auxiliary and vacuum hoppers often requires that the conduit be oriented at a substantial angle. This makes it more difficult to convey viscous materials owing to frictional forces developed within the conduit. Moreover, connection joints are required at the ends of the conduit, and these can be difficult to precisely align under working plant conditions. Cleanout of the pipes is also a problem, especially when the pipes are under load.
There is accordingly a real and unsatisfied need in the art for improved dual-hopper product feeder system for use with piston-type pumps which eliminate the need for separate auxiliary hoppers and conduits between hoppers.
The present invention overcomes the problems outlined above, and provides pumping apparatus in the form of a piston-type pump including a chamber with a product inlet and a pair of outlets, where the chamber adapted to receive product to be pumped. A pair of reciprocal piston assemblies are located within the chamber serve to successively deliver charges of product to the chamber outlets. A dual-hopper assembly is disposed above the chamber for product delivery purposes. This dual-hopper assembly includes a lower vacuum hopper having an upstanding hopper body and a closure section with a passageway therethrough. An upper atmospheric pressure hopper is disposed over and operably coupled with the lower vacuum hopper section so as to establish communication between the upper and lower hoppers. A selectively operable valve unit is also located adjacent the passageway and is operable in alternate positions thereof to open and close the passageway.
In preferred forms, the lower hopper section is hingedly mounted relative to the lower hopper body for opening and closing of the section as well as the upper hopper. The upper and lower hoppers are normally of generally frustoconical configuration and are substantially concentrically arranged.
A product feeding assembly can also be provided as a retrofit for existing, conventional system-pumps. Advantageously, such a feeding assembly would include a lower vacuum hopper section in the form of a hopper wall with an apertured top, together with a permanently fixed upper atmospheric hopper secured to the section top. A valve unit also forms a part of the product feeding assembly and includes a valve plate disposed adjacent the communicating passageway between the upper hopper and the lower hopper section.
As described previously, the conventional practice with piston pumps such as the pump 10 of
The present invention is designed to overcome the deficiencies of this conventional approach, without sacrificing product throughput or quality. Referring to
Turning next to
The dual hopper product feeding assembly 22 broadly includes a lower vacuum hopper 42 together with an upper, open-top, atmospheric pressure hopper 44 and a valve assembly 45. As shown, the hoppers 42, 44 are both generally frustoconical in configuration and are substantially concentrically arranged, while the valve assembly 45 operates between the hoppers 42 and 44.
Lower vacuum hopper 42 in preferred forms is made up of a lower, upstanding hopper body 46 which is permanently affixed to the top of pump body 24 and defines with the latter the product inlet for pump chamber 26. Additionally, the lower vacuum hopper 42 has an upper section 48 which cooperates with body 46 to form the complete lower vacuum hopper. The section 48 is made up of an upper frustoconical wall section 50 having a bottom wall 51, with the section 50 surmounted by an arcuate, dome-like top 52. The top 52 has a central passageway 54 which establishes communication between hopper 44 and the section 48 (and thus the lower vacuum hopper 42). An upstanding tubular vacuum coupler 56 is also supported by top 52 and permits attachment of a vacuum pump (not shown) for maintaining vacuum conditions within hopper 42 as desired. A second tubular coupler 58 is also supported by top 52 and permits use of a gauge 60 and photoelectric eye 62 which are used to monitor operation of the assembly 22 and pump 10. As best seen in
The upper hopper 44 includes a frustoconical sidewall 66 defining an open top 68. The lower end of sidewall 66 includes an arcuate section 70 which extends below the top 52 (see
The valve assembly 45 includes a valve plate 72 which is designed for selective opening and closing of passageway 54. The plate 72 is supported by an elongated, upstanding rod 74 shiftable within a housing 76. The housing 76 also supports a drive 78 coupled with the rod 74 for reciprocation thereof. The drive 78 may be in the form of a piston and cylinder assembly or an electric or hydraulic motor.
The section 48 and upper hopper 44 are hingedly mounted to the pump 10 by means of support 80. This allows the section 48 and hopper 44 to be shifted between an operative position illustrated in bold lines in
During use of the pump 10 equipped with the assembly 22, the product to be pumped is first delivered to open-top upper hopper 44. This may be done through a conventional bucket loader or by manually dumping product into the hopper. As pumping proceeds, the valve assembly 45 is periodically operated in order to open passageway 54, allowing product to pass directly into lower vacuum hopper 42. Once the hopper 42 is full, the valve assembly 45 is actuated to close plate 72 against the defining walls of passageway 54, so that appropriate vacuum conditions can again be established within lower chamber 42. Product within chamber 42 is delivered to chamber 26 where the piston and sleeve assemblies 34, 36 are operated to deliver charges of product to the outlet valve 32.
The invention may be practiced through production of complete pumps having the dual-hopper product feeding assembly 22. Alternately, a retrofit assembly can be fabricated, made up of the section 48, hopper 44 and valve assembly 45. This retrofit unit can be attached to an existing pump in lieu of the standard upper vacuum hopper section originally provided with the pump.
