1. A filter element for insertion into a holder having at least one substantially flat end wall, the filter element comprising:
a filter web material pleated in a zigzag manner so as to define a plurality of pleats; and
at least one end face associated with the flat end wall and being curved outward in a defined convex manner, wherein the end face is configured to rest leak-tight against the end wall without corrugation and under elastic pre-tension when the filter element is inserted into the holder.
2. The filter element as recited in claim 1, wherein the filter web includes a non-woven material.
3. The filter element as recited in claim 2, wherein the leak-tight relationship between the end face and the end wall is due to at least one of a selection of the web material and a conditioning of the end face.
4. The filter element as recited in claim 1, wherein the holder is one of a filter frame and a filter housing.
5. The filter element as recited in claim 1, wherein the end face is disposed in a direction of the plurality of pleat.
6. The filter element as recited in claim 1, wherein the end face includes a pleat runout region having a convex curvature.
7. The filter element as recited in claim 6, wherein the filter element is stiffened in the pleat runout region.
8. The filter element as recited in claim 1, wherein the filter element is a combination filter, the filter web includes at least one layer of a particle-filtering material and at least one layer of a chemical contaminant filtering material.
9. The filter element as recited in claim 8, chemical contaminant filtering material includes an adsorbent material.
10. The filter element as recited in claim 9, wherein the adsorbent material includes activated carbon.
11. A filter system comprising:
a holder having at least one substantially flat end wall; and
a filter element inserted into including a filter web material pleated in a zigzag manner so as to define a plurality of pleats and at least one end face curved outward in a defined convex manner and resting leak-tight against the end wall without corrugation and under elastic pre-tension.
12. The filter element as recited in claim 11, wherein the holder is one of a filter frame and a filter housing.
13. The filter system as recited in claim 11, further comprising an additional labyrinth seal disposed between the at least one end face and the respective at least one end wall.
14. The filter element as recited in claim 13, wherein the labyrinth seal includes a sword in the holder.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A heat exchanger for cooling a gas from a first temperature to a second temperature, the exchanger comprising a first heat exchanging chamber, a second heat exchanging chamber and an array of heat pipes which are arranged to extend from within the first heat exchanging chamber to within the second heat exchanging chamber;
the first heat exchanging chamber comprising an inlet for receiving a coolant into the chamber and an outlet through which the coolant can exit the first chamber, the coolant being arranged to pass over the portion of the heat pipes which extend within the first chamber;
the second heat exchanging chamber comprising an inlet for receiving the gas at a first temperature into the chamber and an outlet through which the gas can exit the second chamber at a second temperature; wherein,
the gas is arranged to pass along the second chamber between the inlet and the outlet along a path comprising a substantially constant cross-sectional area to minimize the pressure drop between the inlet and the outlet.
2. A heat exchanger according to claim 1, further comprising a deflection plate which is arranged to deflect the passage of gas across the heat pipes in passing between the inlet and the outlet of the second chamber.
3. A heat exchanger according to claim 2, wherein the deflection plate is arranged to cause the gas to pass predominantly across the heat pipes as opposed to along the heat pipes.
4. A heat exchanger according to claim 2, wherein the deflection plate extends substantially radially of the second chamber and comprises an outer periphery which is spaced from a side wall of the second chamber.
5. A heat exchanger according to claim 2, wherein the deflection plate comprises a gate disposed therein which is arranged to open and close a central region of the deflection plate.
6. A heat exchanger according to claim 5, wherein the outlet of the first chamber comprises a sensor for sensing the temperature of the liquid exiting the first chamber.
7. A heat exchanger according to claim 6, wherein the gate is arranged to open and close in dependence on the sensed temperature of the liquid exiting the first chamber.
8. A heat exchanger according to claim 1, wherein the inlet and outlet of the second chamber are disposed on a longitudinal axis of the heat exchanger.
9. A heat exchanger according to claim 1, wherein the array of heat pipes comprises heat pipes arranged in substantially concentric circular rows.
10. A heat exchanger according to claim 1, wherein the heat pipes are orientated substantially parallel to each other.
11. A heat exchanger according to claim 1, wherein the rows of heat pipes comprise a plurality of flow disturbers disposed at separated positions along the rows and which serve to create a turbulent flow of liquid within the row.
12. A heat exchanger according to claim 11, wherein the flow disturbers comprise a plurality of rods which extend along the length of the first chamber substantially parallel to the heat pipes.
13. A heat exchanger according to claim 12, wherein successive rods along each row are disposed at opposite sides of the row to redirect the flow of liquid along the row.
14. A heat exchanger according claim 1, wherein the first and second heat exchanging chambers are separated by a separation plate, through which the heat pipes extend.
15. A heat exchanger according to claim 14, wherein the heat pipes extend in sealing relation with the separation plate via sealing means.
16. A heat exchanger according to claim 15, wherein the sealing means comprises a collar separately disposed around each heat pipe which is arranged to compress a sealing ring against the separation plate.
17. A heat exchanger according to claim 1, wherein the first chamber further comprises a compression plate disposed above the heat pipes, which is arranged to abut the upper region of the heat pipes at one side thereof and comprises a plurality of compression springs disposed on the other side thereof.
18. A heat exchanger according to claim 17, wherein the compression springs are arranged to extend against a lid of the first chamber and act to urge the compression plate against the heat pipes and thus the heat pipes within the separation plate.