GB2162078A - Filter press - Google Patents

Abstract

A filter press has each end plate constituted by a hollow pressure vessel 11, 12 adapted to be pressurised by fluid to balance the compressive pressure to which the filter plates are subjected. The pressurising is by means of an internal bellows 16 within each pressure vessel, whose inner end face is flexible and exposed to the slurry being fed into the press and whose closed interior is liquid-filled. <IMAGE>

Description

SPECIFICATION A filter press This invention relates to filter presses such as are employed, interalia, in dewatering sludge, sewage and coal tailings, and relates in particular to improvements in or relating to the filter press disclosed in our British Patent Application No.

8414610 filed 8th June 1 984.

In our aforesaid Patent Application we disclose a filter press in which at least one of the end frames, preferably both, is constituted by a hollow pressure vessel adapted to be pressurised by fluid to balance the compressive pressure to which the filter plates are subjected. The pressurising fluid may be the fluid product to be filtered or it may be a separate and different fluid, and the two pressure vessels are externally connected for fluid communication, there being means provided in said external connections to ensure equalisation of pressure therein.

According to this invention the improvement or modification in the filter press disclosed in our aforesaid Patent Application consists in pressurising each end pressure vessel by means of an internal bellows or other expandible structure (hereinafter simply called "bellows") responsive to the fluid product being pressure fed through the filter press.

Preferably each end pressure vessel has extending therein a fluid, preferably liquid, filled bellows of closed construction but with a flexible membrane at the filter press interior, which membrane and consequently the liquid-filled bellows is subject to filter press pressure.

As a result both end pressure vessels are equally pressurised without the need to provide an external pressure generating system.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing which shows a side view of a filter press according to the invention.

The filter press comprises a filter plate pack generally indicated at 10 disposed and compressible between two end frames which are constituted by two closed hollow pressure vessels 11, 12, each being of part-spherical configuration with a flat pressure face 11A, 12A.

The customary filter plate moving equipment or gear is generally indicated at 13.

The pressure vessel 11 is the fixed or stationary end frame while the pressure vessel 12 is, as can be seen, the movable or tightening end frame.

Each pressure vessel 11, 12 has fixed thereto four brackets or lugs 11 B, 12B spaced 90 apart.

Each corresponding pair of brackets 11 B and 1 2B is connected by a rod or shaft at the pressure vessel 11 end of the filter press to a double acting hydraulic cylinder 14.

The inlet feed for the material to be filtered is generally indicated at 15 and, in this example, is offcentre of the filter plate pack 10.

According to this invention the pressurising of the end pressure vessels 11, 12 is effected internally.

In each pressure vessel 11, 12 there is disposed an expandible liquid-filled bellows 16 of closed construction supported in the respective flat pressure face 11A, 1 2A. The latter is open at 11 C, 1 2C to the filter press interior, i.e. to the filter plate pack 10 through which product to be filtered is being fed under pressure.

Each bellows 16 at its respective pressure face opening is closed by a flexible membrane adapted to respond to the pressure in the filter plate pack 10.

As a result both end pressure vessels 11, 12 are equally and simultaneously pressurised by, and to the same degree as, the product.

1. A filter press in which the end frames are each constituted by a hollow pressure vessel adapted to be pressurised by an internal bellows or other expandible structure (hereinafter simply called "bellow") responsive to the fluid product being pressure fed through the filter press.

2. A filter press as claimed in claim 1, in which each hollow pressure vessel has extending therein a fluid-filled bellows of closed construction but with a flexible membrane at the filter press interior, which membrane and consequently the fluid-filled bellows is subject to filter press pressure.

3. A filter press as claimed in claim 2, in which each bellows is filled with liquid.

4. A filter press, substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A filter press This invention relates to filter presses such as are employed, interalia, in dewatering sludge, sewage and coal tailings, and relates in particular to improvements in or relating to the filter press disclosed in our British Patent Application No. 8414610 filed 8th June 1 984. In our aforesaid Patent Application we disclose a filter press in which at least one of the end frames, preferably both, is constituted by a hollow pressure vessel adapted to be pressurised by fluid to balance the compressive pressure to which the filter plates are subjected. The pressurising fluid may be the fluid product to be filtered or it may be a separate and different fluid, and the two pressure vessels are externally connected for fluid communication, there being means provided in said external connections to ensure equalisation of pressure therein. According to this invention the improvement or modification in the filter press disclosed in our aforesaid Patent Application consists in pressurising each end pressure vessel by means of an internal bellows or other expandible structure (hereinafter simply called "bellows") responsive to the fluid product being pressure fed through the filter press. Preferably each end pressure vessel has extending therein a fluid, preferably liquid, filled bellows of closed construction but with a flexible membrane at the filter press interior, which membrane and consequently the liquid-filled bellows is subject to filter press pressure. As a result both end pressure vessels are equally pressurised without the need to provide an external pressure generating system. An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing which shows a side view of a filter press according to the invention. The filter press comprises a filter plate pack generally indicated at 10 disposed and compressible between two end frames which are constituted by two closed hollow pressure vessels 11, 12, each being of part-spherical configuration with a flat pressure face 11A, 12A. The customary filter plate moving equipment or gear is generally indicated at 13. The pressure vessel 11 is the fixed or stationary end frame while the pressure vessel 12 is, as can be seen, the movable or tightening end frame. Each pressure vessel 11, 12 has fixed thereto four brackets or lugs 11 B, 12B spaced 90 apart. Each corresponding pair of brackets 11 B and 1 2B is connected by a rod or shaft at the pressure vessel 11 end of the filter press to a double acting hydraulic cylinder 14. The inlet feed for the material to be filtered is generally indicated at 15 and, in this example, is offcentre of the filter plate pack 10. According to this invention the pressurising of the end pressure vessels 11, 12 is effected internally. In each pressure vessel 11, 12 there is disposed an expandible liquid-filled bellows 16 of closed construction supported in the respective flat pressure face 11A, 1 2A. The latter is open at 11 C, 1 2C to the filter press interior, i.e. to the filter plate pack 10 through which product to be filtered is being fed under pressure. Each bellows 16 at its respective pressure face opening is closed by a flexible membrane adapted to respond to the pressure in the filter plate pack 10. As a result both end pressure vessels 11, 12 are equally and simultaneously pressurised by, and to the same degree as, the product. CLAIMS

1. A filter press in which the end frames are each constituted by a hollow pressure vessel adapted to be pressurised by an internal bellows or other expandible structure (hereinafter simply called "bellow") responsive to the fluid product being pressure fed through the filter press.

2. A filter press as claimed in claim 1, in which each hollow pressure vessel has extending therein a fluid-filled bellows of closed construction but with a flexible membrane at the filter press interior, which membrane and consequently the fluid-filled bellows is subject to filter press pressure.

3. A filter press as claimed in claim 2, in which each bellows is filled with liquid.

4. A filter press, substantially as hereinbefore described with reference to the accompanying drawings.