The present invention relates to an apparatus having at least one hose roller pump, wherein the hose roller pump has at least one pump bed and at least one hose or hose part inserted or insertable into the pump bed, and having at least one pressure detection means which is arranged downstream of the hose roller pump and by means of which the time extent of the pressure of a fluid conveyed by means of the hose roller pump can be determined, and having at least one evaluation means by means of which the occlusion of the hose or hose part inserted or insertable into the pump bed can be monitored with reference to the time difference and/or to the angular difference between at least one maximum and at least one minimum of the determined time extent of the pressure and/or with reference to a local minimum of the determined time extent of the pressure. The invention furthermore in particular relates to a method therefor.