Are those applications with high percentage of solids?
If so there are a few seals out there that started out in the Mining industry that don't use a Plan 32 (external flush to cool, clean, or keep solids from the seal faces). The seal faces will usually still be wetted by the process fluid, some may be a version of a dry gas seal (I wouldn't bet on that though).
Many times they will stilll use water as a quench, Plan 62 (a fluid injected on the atmospheric side of the seal to add or remove heat from the faces, or to control oxidation of process fluids) to cool the faces. The quench won't enter the process. The quench fluid is usually contained by a close tolerance bushing or a lip seal of some sort. You will have to make provision for the quench fluid to go somewhere that won't be a saftey hazard or a housekeeping issue.
Some are used as pressurized or non-pressurized dual seals too, depending upon the concentration of the solids. An easy explanation of the non-pressurized version is that the seal uses a second mechanical seal to contain a quench. The pressurized version of the seal will also use a second mechanical seal but the fluid between the two will be at a higher pressure than the process fluid in the seal chamber of the pump. In this case the pressurized barrier fluid (water or a thin oil) will leak into the process at atmosphere at a very low rate- you'll hardly notice. The advantage is that it provides cool, clean lubricaton for the seal faces and that you have positive containment of the process fluid as long as there is high pressure fluid between the two seals.
Another thing to think about is the seal chamber itself. If your pumps use small bore seal chambers like those used with packing, you may want to think about upgrading to large or taper bore seal chambers. Larger seal chambers promote better cooling and less turbulent circulation of the process fluid around the seal. Less turbulent flow means less abrasion of the hardware and seal faces.
Important things to look for are robust seal faces and hardware. Depending upon the application multiple springs may be acceptable, and others may require a large single springs. Again depending upon the application, springs in the process fluid may be acceptable, others may requre the springs to remain outside to keep from clogging.
As mentioned above your trusted seal vendor will be a big help.